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Author SHA1 Message Date
e917272c60 Give each element a serial number (#22)
Give each `Element` a serial number, which identifies it uniquely. The serial number is assigned by the `Element::new` constructor.

Because disallows potentially unsafe global state (at least without explicit `unsafe` blocks), the next serial number is stored in a thread-safe static atomic variable (`assembly::NEXT_ELEMENT_SERIAL`), as suggested in [this StackOverflow answer](https://stackoverflow.com/a/32936288). Since the overhead for keeping track of memory ordering should be minimal, we're using the strongest available ordering: [sequentially consistent](https://marabos.nl/atomics/memory-ordering.html#seqcst).

Resolves #20.

Co-authored-by: Aaron Fenyes <aaron.fenyes@fareycircles.ooo>
Reviewed-on: #22
Co-authored-by: Vectornaut <vectornaut@nobody@nowhere.net>
Co-committed-by: Vectornaut <vectornaut@nobody@nowhere.net>
2024-11-22 02:25:10 +00:00
65cee1ecc2 Clean up the outline view (#19)
Clean up the source code and interface of the outline view. In addition, [fix a bug](commit/6e42681b719d7ec97c4225ca321225979bf87b56) that could cause `Assembly::realize` to react to itself under certain circumstances. Those circumstances arose, making the bug noticeable, while this branch was being written.

#### Source code

- Modularize the `Outline` component into smaller components.
- Switch from static iteration to dynamic Sycamore lists. This reduces the amount of re-rendering that happens when an element or constraint changes. It also allows constraint details to stay open or closed during constraint updates, rather than resetting to closed.
- Make `Element::index` private, as discussed [here](pulls/15#issuecomment-1816).

#### Interface

- Make constraints editable, updating the assembly realization on input. Flag constraints where the Lorentz product value doesn't parse.
- Round element vector coordinates to prevent the displayed strings from overlapping.

Note that issue #20 was created by this PR, but it will be addressed shortly.

Co-authored-by: Aaron Fenyes <aaron.fenyes@fareycircles.ooo>
Reviewed-on: #19
Co-authored-by: Vectornaut <vectornaut@nobody@nowhere.net>
Co-committed-by: Vectornaut <vectornaut@nobody@nowhere.net>
2024-11-15 03:32:47 +00:00
707618cdd3 Integrate engine into application prototype (#15)
Port the engine prototype to Rust, integrate it into the application prototype, and use it to enforce the constraints.

### Features

To see the engine in action:

1. Add a constraint by shift-clicking to select two spheres in the outline view and then hitting the 🔗 button
2. Click a summary arrow to see the outline item for the new constraint
2. Set the constraint's Lorentz product by entering a value in the text field at the right end of the outline item
   * *The display should update as soon as you press* Enter *or focus away from the text field*

The checkbox at the left end of a constraint outline item controls whether the constraint is active. Activating a constraint triggers a solution update. (Deactivating a constraint doesn't, since the remaining active constraints are still satisfied.)

### Precision

The Julia prototype of the engine uses a generic scalar type, so you can pass in any type the linear algebra functions are implemented for. The examples use the [adjustable-precision](https://docs.julialang.org/en/v1/base/numbers/#Base.MPFR.setprecision) `BigFloat` type.

In the Rust port of the engine, the scalar type is currently fixed at `f64`. Switching to generic scalars shouldn't be too hard, but I haven't looked into [which other types](https://www.nalgebra.org/docs/user_guide/generic_programming) the linear algebra functions are implemented for.

### Testing

To confirm quantitatively that the Rust port of the engine is working, you can go to the `app-proto` folder and:

* Run some automated tests by calling `cargo test`.
* Inspect the optimization process in a few examples calling the `run-examples` script. The first example that prints is the same as the Irisawa hexlet example from the engine prototype. If you go into `engine-proto/gram-test`, launch Julia, and then

  ```
  include("irisawa-hexlet.jl")
  for (step, scaled_loss) in enumerate(history_alt.scaled_loss)
    println(rpad(step-1, 4), " | ", scaled_loss)
  end
  ```

  you should see that it prints basically the same loss history until the last few steps, when the lower default precision of the Rust engine really starts to show.

### A small engine revision

The Rust port of the engine improves on the Julia prototype in one part of the constraint-solving routine: projecting the Hessian onto the subspace where the frozen entries stay constant. The Julia prototype does this by removing the rows and columns of the Hessian that correspond to the frozen entries, finding the Newton step from the resulting "compressed" Hessian, and then adding zero entries to the Newton step in the appropriate places. The Rust port instead replaces each frozen row and column with its corresponding standard unit vector, avoiding the finicky compressing and decompressing steps.

To confirm that this version of the constraint-solving routine works the same as the original, I implemented it in Julia as `realize_gram_alt_proj`. The solutions we get from this routine match the ones we get from the original `realize_gram` to very high precision, and in the simplest examples (`sphere-in-tetrahedron.jl` and `tetrahedron-radius-ratio.jl`), the descent paths also match to very high precision. In a more complicated example (`irisawa-hexlet.jl`), the descent paths diverge about a quarter of the way into the search, even though they end up in the same place.

Co-authored-by: Aaron Fenyes <aaron.fenyes@fareycircles.ooo>
Reviewed-on: #15
Co-authored-by: Vectornaut <vectornaut@nobody@nowhere.net>
Co-committed-by: Vectornaut <vectornaut@nobody@nowhere.net>
2024-11-12 00:46:16 +00:00
86fa682b31 feat: Application prototype (#14)
Creates a prototype user interface for dyna3 in the `app-proto` folder. The interface is dynamically constructed using [Sycamore](https://sycamore.dev).

The prototype includes:

  * An application state model (the `AppState` type)
    * A constraint problem model (the `Assembly` type), used in the application state
  * Two views
    * A 3D rendering of the assembly (the `Display` component)
    * A list of elements and constraints (the `Outline` component)

The following features confirm that the views can reflect and send input to the model:

  * You can select elements by clicking and shift-clicking them in the outline. The selected elements are highlighted in the display.
  * You can add elements using a button above the outline. The new elements appear in the display.

Co-authored-by: Aaron Fenyes <aaron.fenyes@fareycircles.ooo>
Reviewed-on: #14
Co-authored-by: Vectornaut <vectornaut@nobody@nowhere.net>
Co-committed-by: Vectornaut <vectornaut@nobody@nowhere.net>
2024-10-21 23:38:27 +00:00
b92be312e8 Engine prototype (#13)
This PR adds code for a Julia-language prototype of a configuration solver, in the `engine-proto` folder. It uses Julia version 1.10.0.

### Approaches
Development of this PR tried two broad approaches to the constraint geometry problem. Each one suggested various solution techniques. The Gram matrix approach, with the low-rank factorization technique, seems the most promising.

- **Algebraic** *(In the `alg-test` subfolder).* Write the constraints as polynomials in the inversive coordinates of the elements, and use computational algebraic geometry techniques to solve the resulting system. We tried the following techniques.
  - **Gröbner bases** *(`Engine.Algebraic.jl`).* Symbolic. Find a Gröbner basis for the ideal generated by the constraint equations. Information about the solution variety, like its codimension, is then relatively easy to extract.
  - **Homotopy continuation** *(`Engine.Numerical.jl`).* Numerical. Cut the solution set along a random hyperplane to get a generic zero-dimensional slice, and then use a fancy homotopy technique to approximate the points in that slice.

  A few notes about our experiences can be found on the [engine prototype](wiki/Engine-prototype) wiki page.
- **Gram matrix** *(in the `gram-test` subfolder).* A construction is described completely, up to conformal transformations, by the Gram matrix of the vectors representing its elements. Express the constraints as fixed entries of the Gram matrix, and use numerical linear algebra techniques to find a list of vectors whose Gram matrix fits the bill. We tried the following techniques.
  - **LDL decomposition** *(`gram-test.sage`, `gram-test.jl`, `overlap-test.jl`).* Find a cluster of up to five elements whose Gram matrix is completely filled in by the constraints. Use LDL decomposition to find a list of vectors with that Gram matrix. This technique can be made algebraic, as seen in `overlap-test.jl`.
  - **Low-rank factorization** *(source files listed in findings section).* Write down a quadratic loss function that says how far a set of vectors is from meeting the Gram matrix constraints. Use a smooth optimization technique like Newton's method or gradient descent to find a zero of the loss function. In addition to the polished prototype described in the results section, we have an early prototype using an off-the-shelf factorization package (`low-rank-test.jl`) and an visualization of the loss function landscape near global minima (`basin-shapes.jl`).

  The [Gram matrix parameterization](wiki/Gram-matrix-parameterization) wiki page contains detailed notes on this approach.

### Findings

With the algebraic approach, we hit a performance wall pretty quickly as our constructions grew. It was often hard to find real solutions of the polynomial system, since the techniques we use work most naturally in the complex world.

With the Gram matrix approach, on the other hand, we could solve interesting problems in acceptably short times using the low-rank factorization technique. We put the optimization routine in its own module (`Engine.jl`) and used it to solve five example problems:
- `overlapping-pyramids.jl`
- `circles-in-triangle.jl`
- `sphere-in-tetrahedron.jl`
- `tetrahedron-radius-ratio.jl`
- `irisawa-hexlet.jl`

We plan to use low-rank factorization of the Gram matrix in our first app prototype.

### Visualizations

We used the visualizer in the `ganja-test` folder to visually check our low-rank factorization results. The visualizer runs [Ganja.js](https://enkimute.github.io/ganja.js/) in an Electron app, made with [Blink](https://github.com/JuliaGizmos/Blink.jl). Although Ganja.js makes beautiful pictures under most circumstances, we found two obstacles to using it in production.

- It seems to have precision problems with low-curvature spheres.
- We couldn't figure out how to customize its clipping and transparency settings, and the default settings often obscure construction details.

Co-authored-by: Aaron Fenyes <aaron.fenyes@fareycircles.ooo>
Co-authored-by: Glen Whitney <glen@studioinfinity.org>
Reviewed-on: #13
Co-authored-by: Vectornaut <vectornaut@nobody@nowhere.net>
Co-committed-by: Vectornaut <vectornaut@nobody@nowhere.net>
2024-10-21 03:18:47 +00:00
48 changed files with 2390 additions and 1122 deletions

4
app-proto/.gitignore vendored Normal file
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target
dist
profiling
Cargo.lock

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@ -1,15 +1,20 @@
[package]
name = "rust-benchmark"
name = "dyna3"
version = "0.1.0"
authors = ["Aaron"]
authors = ["Aaron Fenyes", "Glen Whitney"]
edition = "2021"
[features]
default = ["console_error_panic_hook"]
[dependencies]
itertools = "0.13.0"
js-sys = "0.3.70"
lazy_static = "1.5.0"
nalgebra = "0.33.0"
sycamore = "0.9.0-beta.2"
rustc-hash = "2.0.0"
slab = "0.4.9"
sycamore = "0.9.0-beta.3"
# The `console_error_panic_hook` crate provides better debugging of panics by
# logging them with `console.error`. This is great for development, but requires
@ -20,10 +25,15 @@ console_error_panic_hook = { version = "0.1.7", optional = true }
[dependencies.web-sys]
version = "0.3.69"
features = [
'CanvasRenderingContext2d',
'HtmlCanvasElement',
'Window',
'Performance'
'HtmlInputElement',
'Performance',
'WebGl2RenderingContext',
'WebGlBuffer',
'WebGlProgram',
'WebGlShader',
'WebGlUniformLocation',
'WebGlVertexArrayObject'
]
[dev-dependencies]

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app-proto/index.html Normal file
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<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8"/>
<title>dyna3</title>
<link data-trunk rel="css" href="main.css"/>
<link href="https://fonts.bunny.net/css?family=fira-sans:ital,wght@0,400;1,400&display=swap" rel="stylesheet">
<link href="https://fonts.bunny.net/css?family=noto-emoji:wght@400&text=%f0%9f%94%97%e2%9a%a0&display=swap" rel="stylesheet">
</head>
<body></body>
</html>

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:root {
--text: #fcfcfc; /* almost white */
--text-bright: white;
--text-invalid: #f58fc2; /* bright pink */
--border: #555; /* light gray */
--border-focus: #aaa; /* bright gray */
--border-invalid: #70495c; /* dusky pink */
--selection-highlight: #444; /* medium gray */
--page-background: #222; /* dark gray */
--display-background: #020202; /* almost black */
}
body {
margin: 0px;
color: var(--text);
background-color: var(--page-background);
font-family: 'Fira Sans', sans-serif;
}
/* sidebar */
#sidebar {
display: flex;
flex-direction: column;
float: left;
width: 450px;
height: 100vh;
margin: 0px;
padding: 0px;
border-width: 0px 1px 0px 0px;
border-style: solid;
border-color: var(--border);
}
/* add-remove */
#add-remove {
display: flex;
gap: 8px;
margin: 8px;
}
#add-remove > button {
width: 32px;
height: 32px;
font-size: large;
}
/* KLUDGE */
/*
for convenience, we're using emoji as temporary icons for some buttons. these
buttons need to be displayed in an emoji font
*/
#add-remove > button.emoji {
font-family: 'Noto Emoji', sans-serif;
}
/* outline */
#outline {
flex-grow: 1;
margin: 0px;
padding: 0px;
overflow-y: scroll;
}
li {
user-select: none;
}
summary {
display: flex;
}
summary.selected {
color: var(--text-bright);
background-color: var(--selection-highlight);
}
summary > div, .constraint {
padding-top: 4px;
padding-bottom: 4px;
}
.element, .constraint {
display: flex;
flex-grow: 1;
padding-left: 8px;
padding-right: 8px;
}
.element-switch {
width: 18px;
padding-left: 2px;
text-align: center;
}
details:has(li) .element-switch::after {
content: '▸';
}
details[open]:has(li) .element-switch::after {
content: '▾';
}
.element-label {
flex-grow: 1;
}
.constraint-label {
flex-grow: 1;
}
.element-representation {
display: flex;
}
.element-representation > div {
padding: 2px 0px 0px 0px;
font-size: 10pt;
font-variant-numeric: tabular-nums;
text-align: right;
width: 56px;
}
.constraint {
font-style: italic;
}
.constraint.invalid {
color: var(--text-invalid);
}
.constraint > input[type=checkbox] {
margin: 0px 8px 0px 0px;
}
.constraint > input[type=text] {
color: inherit;
background-color: inherit;
border: 1px solid var(--border);
border-radius: 2px;
}
.constraint.invalid > input[type=text] {
border-color: var(--border-invalid);
}
.status {
width: 20px;
padding-left: 4px;
text-align: center;
font-family: 'Noto Emoji';
font-style: normal;
}
.invalid > .status::after, details:has(.invalid):not([open]) .status::after {
content: '⚠';
color: var(--text-invalid);
}
/* display */
canvas {
float: left;
margin-left: 20px;
margin-top: 20px;
background-color: var(--display-background);
border: 1px solid var(--border);
border-radius: 16px;
}
canvas:focus {
border-color: var(--border-focus);
}

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app-proto/run-examples Executable file
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# based on "Enabling print statements in Cargo tests", by Jon Almeida
#
# https://jonalmeida.com/posts/2015/01/23/print-cargo/
#
cargo test -- --nocapture engine::tests::irisawa_hexlet_test
cargo test -- --nocapture engine::tests::three_spheres_example
cargo test -- --nocapture engine::tests::point_on_sphere_example

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app-proto/src/add_remove.rs Normal file
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use sycamore::prelude::*;
use web_sys::{console, wasm_bindgen::JsValue};
use crate::{engine, AppState, assembly::{Assembly, Constraint, Element}};
/* DEBUG */
// load an example assembly for testing. this code will be removed once we've
// built a more formal test assembly system
fn load_gen_assemb(assembly: &Assembly) {
let _ = assembly.try_insert_element(
Element::new(
String::from("gemini_a"),
String::from("Castor"),
[1.00_f32, 0.25_f32, 0.00_f32],
engine::sphere(0.5, 0.5, 0.0, 1.0)
)
);
let _ = assembly.try_insert_element(
Element::new(
String::from("gemini_b"),
String::from("Pollux"),
[0.00_f32, 0.25_f32, 1.00_f32],
engine::sphere(-0.5, -0.5, 0.0, 1.0)
)
);
let _ = assembly.try_insert_element(
Element::new(
String::from("ursa_major"),
String::from("Ursa major"),
[0.25_f32, 0.00_f32, 1.00_f32],
engine::sphere(-0.5, 0.5, 0.0, 0.75)
)
);
let _ = assembly.try_insert_element(
Element::new(
String::from("ursa_minor"),
String::from("Ursa minor"),
[0.25_f32, 1.00_f32, 0.00_f32],
engine::sphere(0.5, -0.5, 0.0, 0.5)
)
);
let _ = assembly.try_insert_element(
Element::new(
String::from("moon_deimos"),
String::from("Deimos"),
[0.75_f32, 0.75_f32, 0.00_f32],
engine::sphere(0.0, 0.15, 1.0, 0.25)
)
);
let _ = assembly.try_insert_element(
Element::new(
String::from("moon_phobos"),
String::from("Phobos"),
[0.00_f32, 0.75_f32, 0.50_f32],
engine::sphere(0.0, -0.15, -1.0, 0.25)
)
);
}
/* DEBUG */
// load an example assembly for testing. this code will be removed once we've
// built a more formal test assembly system
fn load_low_curv_assemb(assembly: &Assembly) {
let a = 0.75_f64.sqrt();
let _ = assembly.try_insert_element(
Element::new(
"central".to_string(),
"Central".to_string(),
[0.75_f32, 0.75_f32, 0.75_f32],
engine::sphere(0.0, 0.0, 0.0, 1.0)
)
);
let _ = assembly.try_insert_element(
Element::new(
"assemb_plane".to_string(),
"Assembly plane".to_string(),
[0.75_f32, 0.75_f32, 0.75_f32],
engine::sphere_with_offset(0.0, 0.0, 1.0, 0.0, 0.0)
)
);
let _ = assembly.try_insert_element(
Element::new(
"side1".to_string(),
"Side 1".to_string(),
[1.00_f32, 0.00_f32, 0.25_f32],
engine::sphere_with_offset(1.0, 0.0, 0.0, 1.0, 0.0)
)
);
let _ = assembly.try_insert_element(
Element::new(
"side2".to_string(),
"Side 2".to_string(),
[0.25_f32, 1.00_f32, 0.00_f32],
engine::sphere_with_offset(-0.5, a, 0.0, 1.0, 0.0)
)
);
let _ = assembly.try_insert_element(
Element::new(
"side3".to_string(),
"Side 3".to_string(),
[0.00_f32, 0.25_f32, 1.00_f32],
engine::sphere_with_offset(-0.5, -a, 0.0, 1.0, 0.0)
)
);
let _ = assembly.try_insert_element(
Element::new(
"corner1".to_string(),
"Corner 1".to_string(),
[0.75_f32, 0.75_f32, 0.75_f32],
engine::sphere(-4.0/3.0, 0.0, 0.0, 1.0/3.0)
)
);
let _ = assembly.try_insert_element(
Element::new(
"corner2".to_string(),
"Corner 2".to_string(),
[0.75_f32, 0.75_f32, 0.75_f32],
engine::sphere(2.0/3.0, -4.0/3.0 * a, 0.0, 1.0/3.0)
)
);
let _ = assembly.try_insert_element(
Element::new(
String::from("corner3"),
String::from("Corner 3"),
[0.75_f32, 0.75_f32, 0.75_f32],
engine::sphere(2.0/3.0, 4.0/3.0 * a, 0.0, 1.0/3.0)
)
);
}
#[component]
pub fn AddRemove() -> View {
/* DEBUG */
let assembly_name = create_signal("general".to_string());
create_effect(move || {
// get name of chosen assembly
let name = assembly_name.get_clone();
console::log_1(
&JsValue::from(format!("Showing assembly \"{}\"", name.clone()))
);
batch(|| {
let state = use_context::<AppState>();
let assembly = &state.assembly;
// clear state
assembly.elements.update(|elts| elts.clear());
assembly.elements_by_id.update(|elts_by_id| elts_by_id.clear());
state.selection.update(|sel| sel.clear());
// load assembly
match name.as_str() {
"general" => load_gen_assemb(assembly),
"low-curv" => load_low_curv_assemb(assembly),
_ => ()
};
});
});
view! {
div(id="add-remove") {
button(
on:click=|_| {
let state = use_context::<AppState>();
state.assembly.insert_new_element();
/* DEBUG */
// print updated list of elements by identifier
console::log_1(&JsValue::from("elements by identifier:"));
for (id, key) in state.assembly.elements_by_id.get_clone().iter() {
console::log_3(
&JsValue::from(" "),
&JsValue::from(id),
&JsValue::from(*key)
);
}
}
) { "+" }
button(
class="emoji", /* KLUDGE */ // for convenience, we're using an emoji as a temporary icon for this button
disabled={
let state = use_context::<AppState>();
state.selection.with(|sel| sel.len() != 2)
},
on:click=|_| {
let state = use_context::<AppState>();
let subjects = state.selection.with(
|sel| {
let subject_vec: Vec<_> = sel.into_iter().collect();
(subject_vec[0].clone(), subject_vec[1].clone())
}
);
let lorentz_prod = create_signal(0.0);
let lorentz_prod_valid = create_signal(false);
let active = create_signal(true);
state.assembly.insert_constraint(Constraint {
subjects: subjects,
lorentz_prod: lorentz_prod,
lorentz_prod_text: create_signal(String::new()),
lorentz_prod_valid: lorentz_prod_valid,
active: active,
});
state.selection.update(|sel| sel.clear());
/* DEBUG */
// print updated constraint list
console::log_1(&JsValue::from("Constraints:"));
state.assembly.constraints.with(|csts| {
for (_, cst) in csts.into_iter() {
console::log_5(
&JsValue::from(" "),
&JsValue::from(cst.subjects.0),
&JsValue::from(cst.subjects.1),
&JsValue::from(":"),
&JsValue::from(cst.lorentz_prod.get_untracked())
);
}
});
// update the realization when the constraint becomes active
// and valid, or is edited while active and valid
create_effect(move || {
console::log_1(&JsValue::from(
format!("Constraint ({}, {}) updated", subjects.0, subjects.1)
));
lorentz_prod.track();
if active.get() && lorentz_prod_valid.get() {
state.assembly.realize();
}
});
}
) { "🔗" }
select(bind:value=assembly_name) { /* DEBUG */ // example assembly chooser
option(value="general") { "General" }
option(value="low-curv") { "Low-curvature" }
option(value="empty") { "Empty" }
}
}
}
}

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use nalgebra::{DMatrix, DVector};
use rustc_hash::FxHashMap;
use slab::Slab;
use std::{collections::BTreeSet, sync::atomic::{AtomicU64, Ordering}};
use sycamore::prelude::*;
use web_sys::{console, wasm_bindgen::JsValue}; /* DEBUG */
use crate::engine::{realize_gram, PartialMatrix};
// the types of the keys we use to access an assembly's elements and constraints
pub type ElementKey = usize;
pub type ConstraintKey = usize;
pub type ElementColor = [f32; 3];
/* KLUDGE */
// we should reconsider this design when we build a system for switching between
// assemblies. at that point, we might want to switch to hierarchical keys,
// where each each element has a key that identifies it within its assembly and
// each assembly has a key that identifies it within the sesssion
static NEXT_ELEMENT_SERIAL: AtomicU64 = AtomicU64::new(0);
#[derive(Clone, PartialEq)]
pub struct Element {
pub id: String,
pub label: String,
pub color: ElementColor,
pub representation: Signal<DVector<f64>>,
pub constraints: Signal<BTreeSet<ConstraintKey>>,
// a serial number, assigned by `Element::new`, that uniquely identifies
// each element
pub serial: u64,
// the configuration matrix column index that was assigned to this element
// last time the assembly was realized
column_index: usize
}
impl Element {
pub fn new(
id: String,
label: String,
color: ElementColor,
representation: DVector<f64>
) -> Element {
// take the next serial number, panicking if that was the last number we
// had left. the technique we use to panic on overflow is taken from
// _Rust Atomics and Locks_, by Mara Bos
//
// https://marabos.nl/atomics/atomics.html#example-handle-overflow
//
let serial = NEXT_ELEMENT_SERIAL.fetch_update(
Ordering::SeqCst, Ordering::SeqCst,
|serial| serial.checked_add(1)
).expect("Out of serial numbers for elements");
Element {
id: id,
label: label,
color: color,
representation: create_signal(representation),
constraints: create_signal(BTreeSet::default()),
serial: serial,
column_index: 0
}
}
}
#[derive(Clone)]
pub struct Constraint {
pub subjects: (ElementKey, ElementKey),
pub lorentz_prod: Signal<f64>,
pub lorentz_prod_text: Signal<String>,
pub lorentz_prod_valid: Signal<bool>,
pub active: Signal<bool>
}
// a complete, view-independent description of an assembly
#[derive(Clone)]
pub struct Assembly {
// elements and constraints
pub elements: Signal<Slab<Element>>,
pub constraints: Signal<Slab<Constraint>>,
// indexing
pub elements_by_id: Signal<FxHashMap<String, ElementKey>>
}
impl Assembly {
pub fn new() -> Assembly {
Assembly {
elements: create_signal(Slab::new()),
constraints: create_signal(Slab::new()),
elements_by_id: create_signal(FxHashMap::default())
}
}
// --- inserting elements and constraints ---
// insert an element into the assembly without checking whether we already
// have an element with the same identifier. any element that does have the
// same identifier will get kicked out of the `elements_by_id` index
fn insert_element_unchecked(&self, elt: Element) {
let id = elt.id.clone();
let key = self.elements.update(|elts| elts.insert(elt));
self.elements_by_id.update(|elts_by_id| elts_by_id.insert(id, key));
}
pub fn try_insert_element(&self, elt: Element) -> bool {
let can_insert = self.elements_by_id.with_untracked(
|elts_by_id| !elts_by_id.contains_key(&elt.id)
);
if can_insert {
self.insert_element_unchecked(elt);
}
can_insert
}
pub fn insert_new_element(&self) {
// find the next unused identifier in the default sequence
let mut id_num = 1;
let mut id = format!("sphere{}", id_num);
while self.elements_by_id.with_untracked(
|elts_by_id| elts_by_id.contains_key(&id)
) {
id_num += 1;
id = format!("sphere{}", id_num);
}
// create and insert a new element
self.insert_element_unchecked(
Element::new(
id,
format!("Sphere {}", id_num),
[0.75_f32, 0.75_f32, 0.75_f32],
DVector::<f64>::from_column_slice(&[0.0, 0.0, 0.0, 0.5, -0.5])
)
);
}
pub fn insert_constraint(&self, constraint: Constraint) {
let subjects = constraint.subjects;
let key = self.constraints.update(|csts| csts.insert(constraint));
let subject_constraints = self.elements.with(
|elts| (elts[subjects.0].constraints, elts[subjects.1].constraints)
);
subject_constraints.0.update(|csts| csts.insert(key));
subject_constraints.1.update(|csts| csts.insert(key));
}
// --- realization ---
pub fn realize(&self) {
// index the elements
self.elements.update_silent(|elts| {
for (index, (_, elt)) in elts.into_iter().enumerate() {
elt.column_index = index;
}
});
// set up the Gram matrix and the initial configuration matrix
let (gram, guess) = self.elements.with_untracked(|elts| {
// set up the off-diagonal part of the Gram matrix
let mut gram_to_be = PartialMatrix::new();
self.constraints.with_untracked(|csts| {
for (_, cst) in csts {
if cst.active.get_untracked() && cst.lorentz_prod_valid.get_untracked() {
let subjects = cst.subjects;
let row = elts[subjects.0].column_index;
let col = elts[subjects.1].column_index;
gram_to_be.push_sym(row, col, cst.lorentz_prod.get_untracked());
}
}
});
// set up the initial configuration matrix and the diagonal of the
// Gram matrix
let mut guess_to_be = DMatrix::<f64>::zeros(5, elts.len());
for (_, elt) in elts {
let index = elt.column_index;
gram_to_be.push_sym(index, index, 1.0);
guess_to_be.set_column(index, &elt.representation.get_clone_untracked());
}
(gram_to_be, guess_to_be)
});
/* DEBUG */
// log the Gram matrix
console::log_1(&JsValue::from("Gram matrix:"));
gram.log_to_console();
/* DEBUG */
// log the initial configuration matrix
console::log_1(&JsValue::from("Old configuration:"));
for j in 0..guess.nrows() {
let mut row_str = String::new();
for k in 0..guess.ncols() {
row_str.push_str(format!(" {:>8.3}", guess[(j, k)]).as_str());
}
console::log_1(&JsValue::from(row_str));
}
// look for a configuration with the given Gram matrix
let (config, success, history) = realize_gram(
&gram, guess, &[],
1.0e-12, 0.5, 0.9, 1.1, 200, 110
);
/* DEBUG */
// report the outcome of the search
console::log_1(&JsValue::from(
if success {
"Target accuracy achieved!"
} else {
"Failed to reach target accuracy"
}
));
console::log_2(&JsValue::from("Steps:"), &JsValue::from(history.scaled_loss.len() - 1));
console::log_2(&JsValue::from("Loss:"), &JsValue::from(*history.scaled_loss.last().unwrap()));
if success {
// read out the solution
for (_, elt) in self.elements.get_clone_untracked() {
elt.representation.update(
|rep| rep.set_column(0, &config.column(elt.column_index))
);
}
}
}
}

464
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use core::array;
use nalgebra::{DMatrix, Rotation3, Vector3};
use sycamore::{prelude::*, motion::create_raf};
use web_sys::{
console,
window,
KeyboardEvent,
WebGl2RenderingContext,
WebGlProgram,
WebGlShader,
WebGlUniformLocation,
wasm_bindgen::{JsCast, JsValue}
};
use crate::AppState;
fn compile_shader(
context: &WebGl2RenderingContext,
shader_type: u32,
source: &str,
) -> WebGlShader {
let shader = context.create_shader(shader_type).unwrap();
context.shader_source(&shader, source);
context.compile_shader(&shader);
shader
}
fn get_uniform_array_locations<const N: usize>(
context: &WebGl2RenderingContext,
program: &WebGlProgram,
var_name: &str,
member_name_opt: Option<&str>
) -> [Option<WebGlUniformLocation>; N] {
array::from_fn(|n| {
let name = match member_name_opt {
Some(member_name) => format!("{var_name}[{n}].{member_name}"),
None => format!("{var_name}[{n}]")
};
context.get_uniform_location(&program, name.as_str())
})
}
// load the given data into the vertex input of the given name
fn bind_vertex_attrib(
context: &WebGl2RenderingContext,
index: u32,
size: i32,
data: &[f32]
) {
// create a data buffer and bind it to ARRAY_BUFFER
let buffer = context.create_buffer().unwrap();
context.bind_buffer(WebGl2RenderingContext::ARRAY_BUFFER, Some(&buffer));
// load the given data into the buffer. the function `Float32Array::view`
// creates a raw view into our module's `WebAssembly.Memory` buffer.
// allocating more memory will change the buffer, invalidating the view.
// that means we have to make sure we don't allocate any memory until the
// view is dropped
unsafe {
context.buffer_data_with_array_buffer_view(
WebGl2RenderingContext::ARRAY_BUFFER,
&js_sys::Float32Array::view(&data),
WebGl2RenderingContext::STATIC_DRAW,
);
}
// allow the target attribute to be used
context.enable_vertex_attrib_array(index);
// take whatever's bound to ARRAY_BUFFER---here, the data buffer created
// above---and bind it to the target attribute
//
// https://developer.mozilla.org/en-US/docs/Web/API/WebGLRenderingContext/vertexAttribPointer
//
context.vertex_attrib_pointer_with_i32(
index,
size,
WebGl2RenderingContext::FLOAT,
false, // don't normalize
0, // zero stride
0, // zero offset
);
}
#[component]
pub fn Display() -> View {
let state = use_context::<AppState>();
// canvas
let display = create_node_ref();
// navigation
let pitch_up = create_signal(0.0);
let pitch_down = create_signal(0.0);
let yaw_right = create_signal(0.0);
let yaw_left = create_signal(0.0);
let roll_ccw = create_signal(0.0);
let roll_cw = create_signal(0.0);
let zoom_in = create_signal(0.0);
let zoom_out = create_signal(0.0);
let turntable = create_signal(false); /* BENCHMARKING */
// change listener
let scene_changed = create_signal(true);
create_effect(move || {
state.assembly.elements.with(|elts| {
for (_, elt) in elts {
elt.representation.track();
}
});
state.selection.track();
scene_changed.set(true);
});
/* INSTRUMENTS */
const SAMPLE_PERIOD: i32 = 60;
let mut last_sample_time = 0.0;
let mut frames_since_last_sample = 0;
let mean_frame_interval = create_signal(0.0);
on_mount(move || {
// timing
let mut last_time = 0.0;
// viewpoint
const ROT_SPEED: f64 = 0.4; // in radians per second
const ZOOM_SPEED: f64 = 0.15; // multiplicative rate per second
const TURNTABLE_SPEED: f64 = 0.1; /* BENCHMARKING */
let mut orientation = DMatrix::<f64>::identity(5, 5);
let mut rotation = DMatrix::<f64>::identity(5, 5);
let mut location_z: f64 = 5.0;
// display parameters
const OPACITY: f32 = 0.5; /* SCAFFOLDING */
const HIGHLIGHT: f32 = 0.2; /* SCAFFOLDING */
const LAYER_THRESHOLD: i32 = 0; /* DEBUG */
const DEBUG_MODE: i32 = 0; /* DEBUG */
/* INSTRUMENTS */
let performance = window().unwrap().performance().unwrap();
// get the display canvas
let canvas = display.get().unchecked_into::<web_sys::HtmlCanvasElement>();
let ctx = canvas
.get_context("webgl2")
.unwrap()
.unwrap()
.dyn_into::<WebGl2RenderingContext>()
.unwrap();
// compile and attach the vertex and fragment shaders
let vertex_shader = compile_shader(
&ctx,
WebGl2RenderingContext::VERTEX_SHADER,
include_str!("identity.vert"),
);
let fragment_shader = compile_shader(
&ctx,
WebGl2RenderingContext::FRAGMENT_SHADER,
include_str!("inversive.frag"),
);
let program = ctx.create_program().unwrap();
ctx.attach_shader(&program, &vertex_shader);
ctx.attach_shader(&program, &fragment_shader);
ctx.link_program(&program);
let link_status = ctx
.get_program_parameter(&program, WebGl2RenderingContext::LINK_STATUS)
.as_bool()
.unwrap();
let link_msg = if link_status {
"Linked successfully"
} else {
"Linking failed"
};
console::log_1(&JsValue::from(link_msg));
ctx.use_program(Some(&program));
/* DEBUG */
// print the maximum number of vectors that can be passed as
// uniforms to a fragment shader. the OpenGL ES 3.0 standard
// requires this maximum to be at least 224, as discussed in the
// documentation of the GL_MAX_FRAGMENT_UNIFORM_VECTORS parameter
// here:
//
// https://registry.khronos.org/OpenGL-Refpages/es3.0/html/glGet.xhtml
//
// there are also other size limits. for example, on Aaron's
// machine, the the length of a float or genType array seems to be
// capped at 1024 elements
console::log_2(
&ctx.get_parameter(WebGl2RenderingContext::MAX_FRAGMENT_UNIFORM_VECTORS).unwrap(),
&JsValue::from("uniform vectors available")
);
// find indices of vertex attributes and uniforms
const SPHERE_MAX: usize = 200;
let position_index = ctx.get_attrib_location(&program, "position") as u32;
let sphere_cnt_loc = ctx.get_uniform_location(&program, "sphere_cnt");
let sphere_sp_locs = get_uniform_array_locations::<SPHERE_MAX>(
&ctx, &program, "sphere_list", Some("sp")
);
let sphere_lt_locs = get_uniform_array_locations::<SPHERE_MAX>(
&ctx, &program, "sphere_list", Some("lt")
);
let color_locs = get_uniform_array_locations::<SPHERE_MAX>(
&ctx, &program, "color_list", None
);
let highlight_locs = get_uniform_array_locations::<SPHERE_MAX>(
&ctx, &program, "highlight_list", None
);
let resolution_loc = ctx.get_uniform_location(&program, "resolution");
let shortdim_loc = ctx.get_uniform_location(&program, "shortdim");
let opacity_loc = ctx.get_uniform_location(&program, "opacity");
let layer_threshold_loc = ctx.get_uniform_location(&program, "layer_threshold");
let debug_mode_loc = ctx.get_uniform_location(&program, "debug_mode");
// create a vertex array and bind it to the graphics context
let vertex_array = ctx.create_vertex_array().unwrap();
ctx.bind_vertex_array(Some(&vertex_array));
// set the vertex positions
const VERTEX_CNT: usize = 6;
let positions: [f32; 3*VERTEX_CNT] = [
// northwest triangle
-1.0, -1.0, 0.0,
-1.0, 1.0, 0.0,
1.0, 1.0, 0.0,
// southeast triangle
-1.0, -1.0, 0.0,
1.0, 1.0, 0.0,
1.0, -1.0, 0.0
];
bind_vertex_attrib(&ctx, position_index, 3, &positions);
// set up a repainting routine
let (_, start_animation_loop, _) = create_raf(move || {
// get the time step
let time = performance.now();
let time_step = 0.001*(time - last_time);
last_time = time;
// get the navigation state
let pitch_up_val = pitch_up.get();
let pitch_down_val = pitch_down.get();
let yaw_right_val = yaw_right.get();
let yaw_left_val = yaw_left.get();
let roll_ccw_val = roll_ccw.get();
let roll_cw_val = roll_cw.get();
let zoom_in_val = zoom_in.get();
let zoom_out_val = zoom_out.get();
let turntable_val = turntable.get(); /* BENCHMARKING */
// update the assembly's orientation
let ang_vel = {
let pitch = pitch_up_val - pitch_down_val;
let yaw = yaw_right_val - yaw_left_val;
let roll = roll_ccw_val - roll_cw_val;
if pitch != 0.0 || yaw != 0.0 || roll != 0.0 {
ROT_SPEED * Vector3::new(-pitch, yaw, roll).normalize()
} else {
Vector3::zeros()
}
} /* BENCHMARKING */ + if turntable_val {
Vector3::new(0.0, TURNTABLE_SPEED, 0.0)
} else {
Vector3::zeros()
};
let mut rotation_sp = rotation.fixed_view_mut::<3, 3>(0, 0);
rotation_sp.copy_from(
Rotation3::from_scaled_axis(time_step * ang_vel).matrix()
);
orientation = &rotation * &orientation;
// update the assembly's location
let zoom = zoom_out_val - zoom_in_val;
location_z *= (time_step * ZOOM_SPEED * zoom).exp();
if scene_changed.get() {
/* INSTRUMENTS */
// measure mean frame interval
frames_since_last_sample += 1;
if frames_since_last_sample >= SAMPLE_PERIOD {
mean_frame_interval.set((time - last_sample_time) / (SAMPLE_PERIOD as f64));
last_sample_time = time;
frames_since_last_sample = 0;
}
// find the map from assembly space to world space
let location = {
let u = -location_z;
DMatrix::from_column_slice(5, 5, &[
1.0, 0.0, 0.0, 0.0, 0.0,
0.0, 1.0, 0.0, 0.0, 0.0,
0.0, 0.0, 1.0, 0.0, u,
0.0, 0.0, 2.0*u, 1.0, u*u,
0.0, 0.0, 0.0, 0.0, 1.0
])
};
let assembly_to_world = &location * &orientation;
// get the assembly
let (
elt_cnt,
reps_world,
colors,
highlights
) = state.assembly.elements.with(|elts| {
(
// number of elements
elts.len() as i32,
// representation vectors in world coordinates
elts.iter().map(
|(_, elt)| elt.representation.with(|rep| &assembly_to_world * rep)
).collect::<Vec<_>>(),
// colors
elts.iter().map(|(key, elt)| {
if state.selection.with(|sel| sel.contains(&key)) {
elt.color.map(|ch| 0.2 + 0.8*ch)
} else {
elt.color
}
}).collect::<Vec<_>>(),
// highlight levels
elts.iter().map(|(key, _)| {
if state.selection.with(|sel| sel.contains(&key)) {
1.0_f32
} else {
HIGHLIGHT
}
}).collect::<Vec<_>>()
)
});
// set the resolution
let width = canvas.width() as f32;
let height = canvas.height() as f32;
ctx.uniform2f(resolution_loc.as_ref(), width, height);
ctx.uniform1f(shortdim_loc.as_ref(), width.min(height));
// pass the assembly
ctx.uniform1i(sphere_cnt_loc.as_ref(), elt_cnt);
for n in 0..reps_world.len() {
let v = &reps_world[n];
ctx.uniform3f(
sphere_sp_locs[n].as_ref(),
v[0] as f32, v[1] as f32, v[2] as f32
);
ctx.uniform2f(
sphere_lt_locs[n].as_ref(),
v[3] as f32, v[4] as f32
);
ctx.uniform3fv_with_f32_array(
color_locs[n].as_ref(),
&colors[n]
);
ctx.uniform1f(
highlight_locs[n].as_ref(),
highlights[n]
);
}
// pass the display parameters
ctx.uniform1f(opacity_loc.as_ref(), OPACITY);
ctx.uniform1i(layer_threshold_loc.as_ref(), LAYER_THRESHOLD);
ctx.uniform1i(debug_mode_loc.as_ref(), DEBUG_MODE);
// draw the scene
ctx.draw_arrays(WebGl2RenderingContext::TRIANGLES, 0, VERTEX_CNT as i32);
// clear the scene change flag
scene_changed.set(
pitch_up_val != 0.0
|| pitch_down_val != 0.0
|| yaw_left_val != 0.0
|| yaw_right_val != 0.0
|| roll_cw_val != 0.0
|| roll_ccw_val != 0.0
|| zoom_in_val != 0.0
|| zoom_out_val != 0.0
|| turntable_val /* BENCHMARKING */
);
} else {
frames_since_last_sample = 0;
mean_frame_interval.set(-1.0);
}
});
start_animation_loop();
});
let set_nav_signal = move |event: KeyboardEvent, value: f64| {
let mut navigating = true;
let shift = event.shift_key();
match event.key().as_str() {
"ArrowUp" if shift => zoom_in.set(value),
"ArrowDown" if shift => zoom_out.set(value),
"ArrowUp" => pitch_up.set(value),
"ArrowDown" => pitch_down.set(value),
"ArrowRight" if shift => roll_cw.set(value),
"ArrowLeft" if shift => roll_ccw.set(value),
"ArrowRight" => yaw_right.set(value),
"ArrowLeft" => yaw_left.set(value),
_ => navigating = false
};
if navigating {
scene_changed.set(true);
event.prevent_default();
}
};
view! {
/* TO DO */
// switch back to integer-valued parameters when that becomes possible
// again
canvas(
ref=display,
width="600",
height="600",
tabindex="0",
on:keydown=move |event: KeyboardEvent| {
if event.key() == "Shift" {
roll_cw.set(yaw_right.get());
roll_ccw.set(yaw_left.get());
zoom_in.set(pitch_up.get());
zoom_out.set(pitch_down.get());
yaw_right.set(0.0);
yaw_left.set(0.0);
pitch_up.set(0.0);
pitch_down.set(0.0);
} else {
if event.key() == "Enter" { /* BENCHMARKING */
turntable.set_fn(|turn| !turn);
scene_changed.set(true);
}
set_nav_signal(event, 1.0);
}
},
on:keyup=move |event: KeyboardEvent| {
if event.key() == "Shift" {
yaw_right.set(roll_cw.get());
yaw_left.set(roll_ccw.get());
pitch_up.set(zoom_in.get());
pitch_down.set(zoom_out.get());
roll_cw.set(0.0);
roll_ccw.set(0.0);
zoom_in.set(0.0);
zoom_out.set(0.0);
} else {
set_nav_signal(event, 0.0);
}
},
on:blur=move |_| {
pitch_up.set(0.0);
pitch_down.set(0.0);
yaw_right.set(0.0);
yaw_left.set(0.0);
roll_ccw.set(0.0);
roll_cw.set(0.0);
}
)
}
}

540
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@ -0,0 +1,540 @@
use lazy_static::lazy_static;
use nalgebra::{Const, DMatrix, DVector, Dyn};
use web_sys::{console, wasm_bindgen::JsValue}; /* DEBUG */
// --- elements ---
#[cfg(test)]
pub fn point(x: f64, y: f64, z: f64) -> DVector<f64> {
DVector::from_column_slice(&[x, y, z, 0.5, 0.5*(x*x + y*y + z*z)])
}
// the sphere with the given center and radius, with inward-pointing normals
pub fn sphere(center_x: f64, center_y: f64, center_z: f64, radius: f64) -> DVector<f64> {
let center_norm_sq = center_x * center_x + center_y * center_y + center_z * center_z;
DVector::from_column_slice(&[
center_x / radius,
center_y / radius,
center_z / radius,
0.5 / radius,
0.5 * (center_norm_sq / radius - radius)
])
}
// the sphere of curvature `curv` whose closest point to the origin has position
// `off * dir` and normal `dir`, where `dir` is a unit vector. setting the
// curvature to zero gives a plane
pub fn sphere_with_offset(dir_x: f64, dir_y: f64, dir_z: f64, off: f64, curv: f64) -> DVector<f64> {
let norm_sp = 1.0 + off * curv;
DVector::from_column_slice(&[
norm_sp * dir_x,
norm_sp * dir_y,
norm_sp * dir_z,
0.5 * curv,
off * (1.0 + 0.5 * off * curv)
])
}
// --- partial matrices ---
struct MatrixEntry {
index: (usize, usize),
value: f64
}
pub struct PartialMatrix(Vec<MatrixEntry>);
impl PartialMatrix {
pub fn new() -> PartialMatrix {
PartialMatrix(Vec::<MatrixEntry>::new())
}
pub fn push_sym(&mut self, row: usize, col: usize, value: f64) {
let PartialMatrix(entries) = self;
entries.push(MatrixEntry { index: (row, col), value: value });
if row != col {
entries.push(MatrixEntry { index: (col, row), value: value });
}
}
/* DEBUG */
pub fn log_to_console(&self) {
let PartialMatrix(entries) = self;
for ent in entries {
let ent_str = format!(" {} {} {}", ent.index.0, ent.index.1, ent.value);
console::log_1(&JsValue::from(ent_str.as_str()));
}
}
fn proj(&self, a: &DMatrix<f64>) -> DMatrix<f64> {
let mut result = DMatrix::<f64>::zeros(a.nrows(), a.ncols());
let PartialMatrix(entries) = self;
for ent in entries {
result[ent.index] = a[ent.index];
}
result
}
fn sub_proj(&self, rhs: &DMatrix<f64>) -> DMatrix<f64> {
let mut result = DMatrix::<f64>::zeros(rhs.nrows(), rhs.ncols());
let PartialMatrix(entries) = self;
for ent in entries {
result[ent.index] = ent.value - rhs[ent.index];
}
result
}
}
// --- descent history ---
pub struct DescentHistory {
pub config: Vec<DMatrix<f64>>,
pub scaled_loss: Vec<f64>,
pub neg_grad: Vec<DMatrix<f64>>,
pub min_eigval: Vec<f64>,
pub base_step: Vec<DMatrix<f64>>,
pub backoff_steps: Vec<i32>
}
impl DescentHistory {
fn new() -> DescentHistory {
DescentHistory {
config: Vec::<DMatrix<f64>>::new(),
scaled_loss: Vec::<f64>::new(),
neg_grad: Vec::<DMatrix<f64>>::new(),
min_eigval: Vec::<f64>::new(),
base_step: Vec::<DMatrix<f64>>::new(),
backoff_steps: Vec::<i32>::new(),
}
}
}
// --- gram matrix realization ---
// the Lorentz form
lazy_static! {
static ref Q: DMatrix<f64> = DMatrix::from_row_slice(5, 5, &[
1.0, 0.0, 0.0, 0.0, 0.0,
0.0, 1.0, 0.0, 0.0, 0.0,
0.0, 0.0, 1.0, 0.0, 0.0,
0.0, 0.0, 0.0, 0.0, -2.0,
0.0, 0.0, 0.0, -2.0, 0.0
]);
}
struct SearchState {
config: DMatrix<f64>,
err_proj: DMatrix<f64>,
loss: f64
}
impl SearchState {
fn from_config(gram: &PartialMatrix, config: DMatrix<f64>) -> SearchState {
let err_proj = gram.sub_proj(&(config.tr_mul(&*Q) * &config));
let loss = err_proj.norm_squared();
SearchState {
config: config,
err_proj: err_proj,
loss: loss
}
}
}
fn basis_matrix(index: (usize, usize), nrows: usize, ncols: usize) -> DMatrix<f64> {
let mut result = DMatrix::<f64>::zeros(nrows, ncols);
result[index] = 1.0;
result
}
// use backtracking line search to find a better configuration
fn seek_better_config(
gram: &PartialMatrix,
state: &SearchState,
base_step: &DMatrix<f64>,
base_target_improvement: f64,
min_efficiency: f64,
backoff: f64,
max_backoff_steps: i32
) -> Option<(SearchState, i32)> {
let mut rate = 1.0;
for backoff_steps in 0..max_backoff_steps {
let trial_config = &state.config + rate * base_step;
let trial_state = SearchState::from_config(gram, trial_config);
let improvement = state.loss - trial_state.loss;
if improvement >= min_efficiency * rate * base_target_improvement {
return Some((trial_state, backoff_steps));
}
rate *= backoff;
}
None
}
// seek a matrix `config` for which `config' * Q * config` matches the partial
// matrix `gram`. use gradient descent starting from `guess`
pub fn realize_gram(
gram: &PartialMatrix,
guess: DMatrix<f64>,
frozen: &[(usize, usize)],
scaled_tol: f64,
min_efficiency: f64,
backoff: f64,
reg_scale: f64,
max_descent_steps: i32,
max_backoff_steps: i32
) -> (DMatrix<f64>, bool, DescentHistory) {
// start the descent history
let mut history = DescentHistory::new();
// find the dimension of the search space
let element_dim = guess.nrows();
let assembly_dim = guess.ncols();
let total_dim = element_dim * assembly_dim;
// scale the tolerance
let scale_adjustment = (gram.0.len() as f64).sqrt();
let tol = scale_adjustment * scaled_tol;
// convert the frozen indices to stacked format
let frozen_stacked: Vec<usize> = frozen.into_iter().map(
|index| index.1*element_dim + index.0
).collect();
// use Newton's method with backtracking and gradient descent backup
let mut state = SearchState::from_config(gram, guess);
for _ in 0..max_descent_steps {
// stop if the loss is tolerably low
history.config.push(state.config.clone());
history.scaled_loss.push(state.loss / scale_adjustment);
if state.loss < tol { break; }
// find the negative gradient of the loss function
let neg_grad = 4.0 * &*Q * &state.config * &state.err_proj;
let mut neg_grad_stacked = neg_grad.clone().reshape_generic(Dyn(total_dim), Const::<1>);
history.neg_grad.push(neg_grad.clone());
// find the negative Hessian of the loss function
let mut hess_cols = Vec::<DVector<f64>>::with_capacity(total_dim);
for col in 0..assembly_dim {
for row in 0..element_dim {
let index = (row, col);
let basis_mat = basis_matrix(index, element_dim, assembly_dim);
let neg_d_err =
basis_mat.tr_mul(&*Q) * &state.config
+ state.config.tr_mul(&*Q) * &basis_mat;
let neg_d_err_proj = gram.proj(&neg_d_err);
let deriv_grad = 4.0 * &*Q * (
-&basis_mat * &state.err_proj
+ &state.config * &neg_d_err_proj
);
hess_cols.push(deriv_grad.reshape_generic(Dyn(total_dim), Const::<1>));
}
}
let mut hess = DMatrix::from_columns(hess_cols.as_slice());
// regularize the Hessian
let min_eigval = hess.symmetric_eigenvalues().min();
if min_eigval <= 0.0 {
hess -= reg_scale * min_eigval * DMatrix::identity(total_dim, total_dim);
}
history.min_eigval.push(min_eigval);
// project the negative gradient and negative Hessian onto the
// orthogonal complement of the frozen subspace
let zero_col = DVector::zeros(total_dim);
let zero_row = zero_col.transpose();
for &k in &frozen_stacked {
neg_grad_stacked[k] = 0.0;
hess.set_row(k, &zero_row);
hess.set_column(k, &zero_col);
hess[(k, k)] = 1.0;
}
// compute the Newton step
/*
we need to either handle or eliminate the case where the minimum
eigenvalue of the Hessian is zero, so the regularized Hessian is
singular. right now, this causes the Cholesky decomposition to return
`None`, leading to a panic when we unrap
*/
let base_step_stacked = hess.cholesky().unwrap().solve(&neg_grad_stacked);
let base_step = base_step_stacked.reshape_generic(Dyn(element_dim), Dyn(assembly_dim));
history.base_step.push(base_step.clone());
// use backtracking line search to find a better configuration
match seek_better_config(
gram, &state, &base_step, neg_grad.dot(&base_step),
min_efficiency, backoff, max_backoff_steps
) {
Some((better_state, backoff_steps)) => {
state = better_state;
history.backoff_steps.push(backoff_steps);
},
None => return (state.config, false, history)
};
}
(state.config, state.loss < tol, history)
}
// --- tests ---
#[cfg(test)]
mod tests {
use std::{array, f64::consts::PI};
use super::*;
#[test]
fn sub_proj_test() {
let target = PartialMatrix(vec![
MatrixEntry { index: (0, 0), value: 19.0 },
MatrixEntry { index: (0, 2), value: 39.0 },
MatrixEntry { index: (1, 1), value: 59.0 },
MatrixEntry { index: (1, 2), value: 69.0 }
]);
let attempt = DMatrix::<f64>::from_row_slice(2, 3, &[
1.0, 2.0, 3.0,
4.0, 5.0, 6.0
]);
let expected_result = DMatrix::<f64>::from_row_slice(2, 3, &[
18.0, 0.0, 36.0,
0.0, 54.0, 63.0
]);
assert_eq!(target.sub_proj(&attempt), expected_result);
}
#[test]
fn zero_loss_test() {
let gram = PartialMatrix({
let mut entries = Vec::<MatrixEntry>::new();
for j in 0..3 {
for k in 0..3 {
entries.push(MatrixEntry {
index: (j, k),
value: if j == k { 1.0 } else { -1.0 }
});
}
}
entries
});
let config = {
let a: f64 = 0.75_f64.sqrt();
DMatrix::from_columns(&[
sphere(1.0, 0.0, 0.0, a),
sphere(-0.5, a, 0.0, a),
sphere(-0.5, -a, 0.0, a)
])
};
let state = SearchState::from_config(&gram, config);
assert!(state.loss.abs() < f64::EPSILON);
}
// this problem is from a sangaku by Irisawa Shintarō Hiroatsu. the article
// below includes a nice translation of the problem statement, which was
// recorded in Uchida Itsumi's book _Kokon sankan_ (_Mathematics, Past and
// Present_)
//
// "Japan's 'Wasan' Mathematical Tradition", by Abe Haruki
// https://www.nippon.com/en/japan-topics/c12801/
//
#[test]
fn irisawa_hexlet_test() {
let gram = PartialMatrix({
let mut entries = Vec::<MatrixEntry>::new();
for s in 0..9 {
// each sphere is represented by a spacelike vector
entries.push(MatrixEntry { index: (s, s), value: 1.0 });
// the circumscribing sphere is tangent to all of the other
// spheres, with matching orientation
if s > 0 {
entries.push(MatrixEntry { index: (0, s), value: 1.0 });
entries.push(MatrixEntry { index: (s, 0), value: 1.0 });
}
if s > 2 {
// each chain sphere is tangent to the "sun" and "moon"
// spheres, with opposing orientation
for n in 1..3 {
entries.push(MatrixEntry { index: (s, n), value: -1.0 });
entries.push(MatrixEntry { index: (n, s), value: -1.0 });
}
// each chain sphere is tangent to the next chain sphere,
// with opposing orientation
let s_next = 3 + (s-2) % 6;
entries.push(MatrixEntry { index: (s, s_next), value: -1.0 });
entries.push(MatrixEntry { index: (s_next, s), value: -1.0 });
}
}
entries
});
let guess = DMatrix::from_columns(
[
sphere(0.0, 0.0, 0.0, 15.0),
sphere(0.0, 0.0, -9.0, 5.0),
sphere(0.0, 0.0, 11.0, 3.0)
].into_iter().chain(
(1..=6).map(
|k| {
let ang = (k as f64) * PI/3.0;
sphere(9.0 * ang.cos(), 9.0 * ang.sin(), 0.0, 2.5)
}
)
).collect::<Vec<_>>().as_slice()
);
let frozen: [(usize, usize); 4] = array::from_fn(|k| (3, k));
const SCALED_TOL: f64 = 1.0e-12;
let (config, success, history) = realize_gram(
&gram, guess, &frozen,
SCALED_TOL, 0.5, 0.9, 1.1, 200, 110
);
let entry_tol = SCALED_TOL.sqrt();
let solution_diams = [30.0, 10.0, 6.0, 5.0, 15.0, 10.0, 3.75, 2.5, 2.0 + 8.0/11.0];
for (k, diam) in solution_diams.into_iter().enumerate() {
assert!((config[(3, k)] - 1.0 / diam).abs() < entry_tol);
}
print!("\nCompleted Gram matrix:{}", config.tr_mul(&*Q) * &config);
if success {
println!("Target accuracy achieved!");
} else {
println!("Failed to reach target accuracy");
}
println!("Steps: {}", history.scaled_loss.len() - 1);
println!("Loss: {}", history.scaled_loss.last().unwrap());
if success {
println!("\nChain diameters:");
println!(" {} sun (given)", 1.0 / config[(3, 3)]);
for k in 4..9 {
println!(" {} sun", 1.0 / config[(3, k)]);
}
}
println!("\nStep │ Loss\n─────┼────────────────────────────────");
for (step, scaled_loss) in history.scaled_loss.into_iter().enumerate() {
println!("{:<4}{}", step, scaled_loss);
}
}
// --- process inspection examples ---
// these tests are meant for human inspection, not automated use. run them
// one at a time in `--nocapture` mode and read through the results and
// optimization histories that they print out. the `run-examples` script
// will run all of them
#[test]
fn three_spheres_example() {
let gram = PartialMatrix({
let mut entries = Vec::<MatrixEntry>::new();
for j in 0..3 {
for k in 0..3 {
entries.push(MatrixEntry {
index: (j, k),
value: if j == k { 1.0 } else { -1.0 }
});
}
}
entries
});
let guess = {
let a: f64 = 0.75_f64.sqrt();
DMatrix::from_columns(&[
sphere(1.0, 0.0, 0.0, 1.0),
sphere(-0.5, a, 0.0, 1.0),
sphere(-0.5, -a, 0.0, 1.0)
])
};
println!();
let (config, success, history) = realize_gram(
&gram, guess, &[],
1.0e-12, 0.5, 0.9, 1.1, 200, 110
);
print!("\nCompleted Gram matrix:{}", config.tr_mul(&*Q) * &config);
if success {
println!("Target accuracy achieved!");
} else {
println!("Failed to reach target accuracy");
}
println!("Steps: {}", history.scaled_loss.len() - 1);
println!("Loss: {}", history.scaled_loss.last().unwrap());
println!("\nStep │ Loss\n─────┼────────────────────────────────");
for (step, scaled_loss) in history.scaled_loss.into_iter().enumerate() {
println!("{:<4}{}", step, scaled_loss);
}
}
#[test]
fn point_on_sphere_example() {
let gram = PartialMatrix({
let mut entries = Vec::<MatrixEntry>::new();
for j in 0..2 {
for k in 0..2 {
entries.push(MatrixEntry {
index: (j, k),
value: if (j, k) == (1, 1) { 1.0 } else { 0.0 }
});
}
}
entries
});
let guess = DMatrix::from_columns(&[
point(0.0, 0.0, 2.0),
sphere(0.0, 0.0, 0.0, 1.0)
]);
let frozen = [(3, 0)];
println!();
let (config, success, history) = realize_gram(
&gram, guess, &frozen,
1.0e-12, 0.5, 0.9, 1.1, 200, 110
);
print!("\nCompleted Gram matrix:{}", config.tr_mul(&*Q) * &config);
print!("Configuration:{}", config);
if success {
println!("Target accuracy achieved!");
} else {
println!("Failed to reach target accuracy");
}
println!("Steps: {}", history.scaled_loss.len() - 1);
println!("Loss: {}", history.scaled_loss.last().unwrap());
println!("\nStep │ Loss\n─────┼────────────────────────────────");
for (step, scaled_loss) in history.scaled_loss.into_iter().enumerate() {
println!("{:<4}{}", step, scaled_loss);
}
}
/* TO DO */
// --- new test placed here to avoid merge conflict ---
// at the frozen indices, the optimization steps should have exact zeros,
// and the realized configuration should match the initial guess
#[test]
fn frozen_entry_test() {
let gram = {
let mut gram_to_be = PartialMatrix::new();
for j in 0..2 {
for k in j..2 {
gram_to_be.push_sym(j, k, if (j, k) == (1, 1) { 1.0 } else { 0.0 });
}
}
gram_to_be
};
let guess = DMatrix::from_columns(&[
point(0.0, 0.0, 2.0),
sphere(0.0, 0.0, 0.0, 1.0)
]);
let frozen = [(3, 0), (3, 1)];
println!();
let (config, success, history) = realize_gram(
&gram, guess.clone(), &frozen,
1.0e-12, 0.5, 0.9, 1.1, 200, 110
);
assert_eq!(success, true);
for base_step in history.base_step.into_iter() {
for index in frozen {
assert_eq!(base_step[index], 0.0);
}
}
for index in frozen {
assert_eq!(config[index], guess[index]);
}
}
}

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@ -0,0 +1,7 @@
#version 300 es
in vec4 position;
void main() {
gl_Position = position;
}

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@ -0,0 +1,234 @@
#version 300 es
precision highp float;
out vec4 outColor;
// --- inversive geometry ---
struct vecInv {
vec3 sp;
vec2 lt;
};
// --- uniforms ---
// assembly
const int SPHERE_MAX = 200;
uniform int sphere_cnt;
uniform vecInv sphere_list[SPHERE_MAX];
uniform vec3 color_list[SPHERE_MAX];
uniform float highlight_list[SPHERE_MAX];
// view
uniform vec2 resolution;
uniform float shortdim;
// controls
uniform float opacity;
uniform int layer_threshold;
uniform bool debug_mode;
// light and camera
const float focal_slope = 0.3;
const vec3 light_dir = normalize(vec3(2., 2., 1.));
const float ixn_threshold = 0.005;
const float INTERIOR_DIMMING = 0.7;
// --- sRGB ---
// map colors from RGB space to sRGB space, as specified in the sRGB standard
// (IEC 61966-2-1:1999)
//
// https://www.color.org/sRGB.pdf
// https://www.color.org/chardata/rgb/srgb.xalter
//
// in RGB space, color value is proportional to light intensity, so linear
// color-vector interpolation corresponds to physical light mixing. in sRGB
// space, the color encoding used by many monitors, we use more of the value
// interval to represent low intensities, and less of the interval to represent
// high intensities. this improves color quantization
float sRGB(float t) {
if (t <= 0.0031308) {
return 12.92*t;
} else {
return 1.055*pow(t, 5./12.) - 0.055;
}
}
vec3 sRGB(vec3 color) {
return vec3(sRGB(color.r), sRGB(color.g), sRGB(color.b));
}
// --- shading ---
struct Fragment {
vec3 pt;
vec3 normal;
vec4 color;
};
Fragment sphere_shading(vecInv v, vec3 pt, vec3 base_color) {
// the expression for normal needs to be checked. it's supposed to give the
// negative gradient of the lorentz product between the impact point vector
// and the sphere vector with respect to the coordinates of the impact
// point. i calculated it in my head and decided that the result looked good
// enough for now
vec3 normal = normalize(-v.sp + 2.*v.lt.s*pt);
float incidence = dot(normal, light_dir);
float illum = mix(0.4, 1.0, max(incidence, 0.0));
return Fragment(pt, normal, vec4(illum * base_color, opacity));
}
float intersection_dist(Fragment a, Fragment b) {
float intersection_sin = length(cross(a.normal, b.normal));
vec3 disp = a.pt - b.pt;
return max(
abs(dot(a.normal, disp)),
abs(dot(b.normal, disp))
) / intersection_sin;
}
// --- ray-casting ---
struct TaggedDepth {
float depth;
float dimming;
int id;
};
// if `a/b` is less than this threshold, we approximate `a*u^2 + b*u + c` by
// the linear function `b*u + c`
const float DEG_THRESHOLD = 1e-9;
// the depths, represented as multiples of `dir`, where the line generated by
// `dir` hits the sphere represented by `v`. if both depths are positive, the
// smaller one is returned in the first component. if only one depth is
// positive, it could be returned in either component
vec2 sphere_cast(vecInv v, vec3 dir) {
float a = -v.lt.s * dot(dir, dir);
float b = dot(v.sp, dir);
float c = -v.lt.t;
float adjust = 4.*a*c/(b*b);
if (adjust < 1.) {
// as long as `b` is non-zero, the linear approximation of
//
// a*u^2 + b*u + c
//
// at `u = 0` will reach zero at a finite depth `u_lin`. the root of the
// quadratic adjacent to `u_lin` is stored in `lin_root`. if both roots
// have the same sign, `lin_root` will be the one closer to `u = 0`
float square_rect_ratio = 1. + sqrt(1. - adjust);
float lin_root = -(2.*c)/b / square_rect_ratio;
if (abs(a) > DEG_THRESHOLD * abs(b)) {
return vec2(lin_root, -b/(2.*a) * square_rect_ratio);
} else {
return vec2(lin_root, -1.);
}
} else {
// the line through `dir` misses the sphere completely
return vec2(-1., -1.);
}
}
void main() {
vec2 scr = (2.*gl_FragCoord.xy - resolution) / shortdim;
vec3 dir = vec3(focal_slope * scr, -1.);
// cast rays through the spheres
const int LAYER_MAX = 12;
TaggedDepth top_hits [LAYER_MAX];
int layer_cnt = 0;
for (int id = 0; id < sphere_cnt; ++id) {
// find out where the ray hits the sphere
vec2 hit_depths = sphere_cast(sphere_list[id], dir);
// insertion-sort the points we hit into the hit list
float dimming = 1.;
for (int side = 0; side < 2; ++side) {
float depth = hit_depths[side];
if (depth > 0.) {
for (int layer = layer_cnt; layer >= 0; --layer) {
if (layer < 1 || top_hits[layer-1].depth <= depth) {
// we're not as close to the screen as the hit before
// the empty slot, so insert here
if (layer < LAYER_MAX) {
top_hits[layer] = TaggedDepth(depth, dimming, id);
}
break;
} else {
// we're closer to the screen than the hit before the
// empty slot, so move that hit into the empty slot
top_hits[layer] = top_hits[layer-1];
}
}
layer_cnt = min(layer_cnt + 1, LAYER_MAX);
dimming = INTERIOR_DIMMING;
}
}
}
/* DEBUG */
// in debug mode, show the layer count instead of the shaded image
if (debug_mode) {
// at the bottom of the screen, show the color scale instead of the
// layer count
if (gl_FragCoord.y < 10.) layer_cnt = int(16. * gl_FragCoord.x / resolution.x);
// convert number to color
ivec3 bits = layer_cnt / ivec3(1, 2, 4);
vec3 color = mod(vec3(bits), 2.);
if (layer_cnt % 16 >= 8) {
color = mix(color, vec3(0.5), 0.5);
}
outColor = vec4(color, 1.);
return;
}
// composite the sphere fragments
vec3 color = vec3(0.);
int layer = layer_cnt - 1;
TaggedDepth hit = top_hits[layer];
Fragment frag_next = sphere_shading(
sphere_list[hit.id],
hit.depth * dir,
hit.dimming * color_list[hit.id]
);
float highlight_next = highlight_list[hit.id];
--layer;
for (; layer >= layer_threshold; --layer) {
// load the current fragment
Fragment frag = frag_next;
float highlight = highlight_next;
// shade the next fragment
hit = top_hits[layer];
frag_next = sphere_shading(
sphere_list[hit.id],
hit.depth * dir,
hit.dimming * color_list[hit.id]
);
highlight_next = highlight_list[hit.id];
// highlight intersections
float ixn_dist = intersection_dist(frag, frag_next);
float max_highlight = max(highlight, highlight_next);
float ixn_highlight = 0.5 * max_highlight * (1. - smoothstep(2./3.*ixn_threshold, 1.5*ixn_threshold, ixn_dist));
frag.color = mix(frag.color, vec4(1.), ixn_highlight);
frag_next.color = mix(frag_next.color, vec4(1.), ixn_highlight);
// highlight cusps
float cusp_cos = abs(dot(dir, frag.normal));
float cusp_threshold = 2.*sqrt(ixn_threshold * sphere_list[hit.id].lt.s);
float cusp_highlight = highlight * (1. - smoothstep(2./3.*cusp_threshold, 1.5*cusp_threshold, cusp_cos));
frag.color = mix(frag.color, vec4(1.), cusp_highlight);
// composite the current fragment
color = mix(color, frag.color.rgb, frag.color.a);
}
color = mix(color, frag_next.color.rgb, frag_next.color.a);
outColor = vec4(sRGB(color), 1.);
}

42
app-proto/src/main.rs Normal file
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mod add_remove;
mod assembly;
mod display;
mod engine;
mod outline;
use rustc_hash::FxHashSet;
use sycamore::prelude::*;
use add_remove::AddRemove;
use assembly::{Assembly, ElementKey};
use display::Display;
use outline::Outline;
#[derive(Clone)]
struct AppState {
assembly: Assembly,
selection: Signal<FxHashSet<ElementKey>>
}
impl AppState {
fn new() -> AppState {
AppState {
assembly: Assembly::new(),
selection: create_signal(FxHashSet::default())
}
}
}
fn main() {
sycamore::render(|| {
provide_context(AppState::new());
view! {
div(id="sidebar") {
AddRemove {}
Outline {}
}
Display {}
}
});
}

207
app-proto/src/outline.rs Normal file
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use itertools::Itertools;
use sycamore::prelude::*;
use web_sys::{
Event,
HtmlInputElement,
KeyboardEvent,
MouseEvent,
wasm_bindgen::JsCast
};
use crate::{AppState, assembly, assembly::{Constraint, ConstraintKey, ElementKey}};
// an editable view of the Lorentz product representing a constraint
#[component(inline_props)]
fn LorentzProductInput(constraint: Constraint) -> View {
view! {
input(
r#type="text",
bind:value=constraint.lorentz_prod_text,
on:change=move |event: Event| {
let target: HtmlInputElement = event.target().unwrap().unchecked_into();
match target.value().parse::<f64>() {
Ok(lorentz_prod) => batch(|| {
constraint.lorentz_prod.set(lorentz_prod);
constraint.lorentz_prod_valid.set(true);
}),
Err(_) => constraint.lorentz_prod_valid.set(false)
};
}
)
}
}
// a list item that shows a constraint in an outline view of an element
#[component(inline_props)]
fn ConstraintOutlineItem(constraint_key: ConstraintKey, element_key: ElementKey) -> View {
let state = use_context::<AppState>();
let assembly = &state.assembly;
let constraint = assembly.constraints.with(|csts| csts[constraint_key].clone());
let other_subject = if constraint.subjects.0 == element_key {
constraint.subjects.1
} else {
constraint.subjects.0
};
let other_subject_label = assembly.elements.with(|elts| elts[other_subject].label.clone());
let class = constraint.lorentz_prod_valid.map(
|&lorentz_prod_valid| if lorentz_prod_valid { "constraint" } else { "constraint invalid" }
);
view! {
li(class=class.get()) {
input(r#type="checkbox", bind:checked=constraint.active)
div(class="constraint-label") { (other_subject_label) }
LorentzProductInput(constraint=constraint)
div(class="status")
}
}
}
// a list item that shows an element in an outline view of an assembly
#[component(inline_props)]
fn ElementOutlineItem(key: ElementKey, element: assembly::Element) -> View {
let state = use_context::<AppState>();
let class = state.selection.map(
move |sel| if sel.contains(&key) { "selected" } else { "" }
);
let label = element.label.clone();
let rep_components = element.representation.map(
|rep| rep.iter().map(
|u| format!("{:.3}", u).replace("-", "\u{2212}")
).collect()
);
let constrained = element.constraints.map(|csts| csts.len() > 0);
let constraint_list = element.constraints.map(
|csts| csts.clone().into_iter().collect()
);
let details_node = create_node_ref();
view! {
li {
details(ref=details_node) {
summary(
class=class.get(),
on:keydown={
move |event: KeyboardEvent| {
match event.key().as_str() {
"Enter" => {
if event.shift_key() {
state.selection.update(|sel| {
if !sel.remove(&key) {
sel.insert(key);
}
});
} else {
state.selection.update(|sel| {
sel.clear();
sel.insert(key);
});
}
event.prevent_default();
},
"ArrowRight" if constrained.get() => {
let _ = details_node
.get()
.unchecked_into::<web_sys::Element>()
.set_attribute("open", "");
},
"ArrowLeft" => {
let _ = details_node
.get()
.unchecked_into::<web_sys::Element>()
.remove_attribute("open");
},
_ => ()
}
}
}
) {
div(
class="element-switch",
on:click=|event: MouseEvent| event.stop_propagation()
)
div(
class="element",
on:click={
move |event: MouseEvent| {
if event.shift_key() {
state.selection.update(|sel| {
if !sel.remove(&key) {
sel.insert(key);
}
});
} else {
state.selection.update(|sel| {
sel.clear();
sel.insert(key);
});
}
event.stop_propagation();
event.prevent_default();
}
}
) {
div(class="element-label") { (label) }
div(class="element-representation") {
Indexed(
list=rep_components,
view=|coord_str| view! {
div { (coord_str) }
}
)
}
div(class="status")
}
}
ul(class="constraints") {
Keyed(
list=constraint_list,
view=move |cst_key| view! {
ConstraintOutlineItem(
constraint_key=cst_key,
element_key=key
)
},
key=|cst_key| cst_key.clone()
)
}
}
}
}
}
// a component that lists the elements of the current assembly, showing the
// constraints on each element as a collapsible sub-list. its implementation
// is based on Kate Morley's HTML + CSS tree views:
//
// https://iamkate.com/code/tree-views/
//
#[component]
pub fn Outline() -> View {
let state = use_context::<AppState>();
// list the elements alphabetically by ID
let element_list = state.assembly.elements.map(
|elts| elts
.clone()
.into_iter()
.sorted_by_key(|(_, elt)| elt.id.clone())
.collect()
);
view! {
ul(
id="outline",
on:click={
let state = use_context::<AppState>();
move |_| state.selection.update(|sel| sel.clear())
}
) {
Keyed(
list=element_list,
view=|(key, elt)| view! {
ElementOutlineItem(key=key, element=elt)
},
key=|(_, elt)| elt.serial
)
}
}
}

View File

@ -8,7 +8,8 @@ using Optim
export
rand_on_shell, Q, DescentHistory,
realize_gram_gradient, realize_gram_newton, realize_gram_optim, realize_gram
realize_gram_gradient, realize_gram_newton, realize_gram_optim,
realize_gram_alt_proj, realize_gram
# === guessing ===
@ -59,11 +60,10 @@ nullmix = [Matrix{Int64}(I, 3, 3) zeros(Int64, 3, 2); zeros(Int64, 2, 3) [-1 1;
unmix = [Matrix{Int64}(I, 3, 3) zeros(Int64, 3, 2); zeros(Int64, 2, 3) [-1 1; 1 1]]
# the Lorentz form
## [old] Q = diagm([1, 1, 1, 1, -1])
Q = [Matrix{Int64}(I, 3, 3) zeros(Int64, 3, 2); zeros(Int64, 2, 3) [0 -2; -2 0]]
# project a matrix onto the subspace of matrices whose entries vanish at the
# given indices
# project a matrix onto the subspace of matrices whose entries vanish away from
# the given indices
function proj_to_entries(mat, indices)
result = zeros(size(mat))
for (j, k) in indices
@ -144,7 +144,7 @@ function realize_gram_gradient(
break
end
# find negative gradient of loss function
# find the negative gradient of the loss function
neg_grad = 4*Q*L*Δ_proj
slope = norm(neg_grad)
dir = neg_grad / slope
@ -233,7 +233,7 @@ function realize_gram_newton(
break
end
# find the negative gradient of loss function
# find the negative gradient of the loss function
neg_grad = 4*Q*L*Δ_proj
# find the negative Hessian of the loss function
@ -314,6 +314,129 @@ function realize_gram_optim(
)
end
# seek a matrix `L` for which `L'QL` matches the sparse matrix `gram` at every
# explicit entry of `gram`. use gradient descent starting from `guess`, with an
# alternate technique for finding the projected base step from the unprojected
# Hessian
function realize_gram_alt_proj(
gram::SparseMatrixCSC{T, <:Any},
guess::Matrix{T},
frozen = CartesianIndex[];
scaled_tol = 1e-30,
min_efficiency = 0.5,
backoff = 0.9,
reg_scale = 1.1,
max_descent_steps = 200,
max_backoff_steps = 110
) where T <: Number
# start history
history = DescentHistory{T}()
# find the dimension of the search space
dims = size(guess)
element_dim, construction_dim = dims
total_dim = element_dim * construction_dim
# list the constrained entries of the gram matrix
J, K, _ = findnz(gram)
constrained = zip(J, K)
# scale the tolerance
scale_adjustment = sqrt(T(length(constrained)))
tol = scale_adjustment * scaled_tol
# convert the frozen indices to stacked format
frozen_stacked = [(index[2]-1)*element_dim + index[1] for index in frozen]
# initialize search state
L = copy(guess)
Δ_proj = proj_diff(gram, L'*Q*L)
loss = dot(Δ_proj, Δ_proj)
# use Newton's method with backtracking and gradient descent backup
for step in 1:max_descent_steps
# stop if the loss is tolerably low
if loss < tol
break
end
# find the negative gradient of the loss function
neg_grad = 4*Q*L*Δ_proj
# find the negative Hessian of the loss function
hess = Matrix{T}(undef, total_dim, total_dim)
indices = [(j, k) for k in 1:construction_dim for j in 1:element_dim]
for (j, k) in indices
basis_mat = basis_matrix(T, j, k, dims)
neg_dΔ = basis_mat'*Q*L + L'*Q*basis_mat
neg_dΔ_proj = proj_to_entries(neg_dΔ, constrained)
deriv_grad = 4*Q*(-basis_mat*Δ_proj + L*neg_dΔ_proj)
hess[:, (k-1)*element_dim + j] = reshape(deriv_grad, total_dim)
end
hess_sym = Hermitian(hess)
push!(history.hess, hess_sym)
# regularize the Hessian
min_eigval = minimum(eigvals(hess_sym))
push!(history.positive, min_eigval > 0)
if min_eigval <= 0
hess -= reg_scale * min_eigval * I
end
# compute the Newton step
neg_grad_stacked = reshape(neg_grad, total_dim)
for k in frozen_stacked
neg_grad_stacked[k] = 0
hess[k, :] .= 0
hess[:, k] .= 0
hess[k, k] = 1
end
base_step_stacked = Hermitian(hess) \ neg_grad_stacked
base_step = reshape(base_step_stacked, dims)
push!(history.base_step, base_step)
# store the current position, loss, and slope
L_last = L
loss_last = loss
push!(history.scaled_loss, loss / scale_adjustment)
push!(history.neg_grad, neg_grad)
push!(history.slope, norm(neg_grad))
# find a good step size using backtracking line search
push!(history.stepsize, 0)
push!(history.backoff_steps, max_backoff_steps)
empty!(history.last_line_L)
empty!(history.last_line_loss)
rate = one(T)
step_success = false
base_target_improvement = dot(neg_grad, base_step)
for backoff_steps in 0:max_backoff_steps
history.stepsize[end] = rate
L = L_last + rate * base_step
Δ_proj = proj_diff(gram, L'*Q*L)
loss = dot(Δ_proj, Δ_proj)
improvement = loss_last - loss
push!(history.last_line_L, L)
push!(history.last_line_loss, loss / scale_adjustment)
if improvement >= min_efficiency * rate * base_target_improvement
history.backoff_steps[end] = backoff_steps
step_success = true
break
end
rate *= backoff
end
# if we've hit a wall, quit
if !step_success
return L_last, false, history
end
end
# return the factorization and its history
push!(history.scaled_loss, loss / scale_adjustment)
L, loss < tol, history
end
# seek a matrix `L` for which `L'QL` matches the sparse matrix `gram` at every
# explicit entry of `gram`. use gradient descent starting from `guess`
function realize_gram(
@ -322,7 +445,6 @@ function realize_gram(
frozen = nothing;
scaled_tol = 1e-30,
min_efficiency = 0.5,
init_rate = 1.0,
backoff = 0.9,
reg_scale = 1.1,
max_descent_steps = 200,
@ -353,20 +475,19 @@ function realize_gram(
unfrozen_stacked = reshape(is_unfrozen, total_dim)
end
# initialize variables
grad_rate = init_rate
# initialize search state
L = copy(guess)
# use Newton's method with backtracking and gradient descent backup
Δ_proj = proj_diff(gram, L'*Q*L)
loss = dot(Δ_proj, Δ_proj)
# use Newton's method with backtracking and gradient descent backup
for step in 1:max_descent_steps
# stop if the loss is tolerably low
if loss < tol
break
end
# find the negative gradient of loss function
# find the negative gradient of the loss function
neg_grad = 4*Q*L*Δ_proj
# find the negative Hessian of the loss function
@ -421,6 +542,7 @@ function realize_gram(
empty!(history.last_line_loss)
rate = one(T)
step_success = false
base_target_improvement = dot(neg_grad, base_step)
for backoff_steps in 0:max_backoff_steps
history.stepsize[end] = rate
L = L_last + rate * base_step
@ -429,7 +551,7 @@ function realize_gram(
improvement = loss_last - loss
push!(history.last_line_L, L)
push!(history.last_line_loss, loss / scale_adjustment)
if improvement >= min_efficiency * rate * dot(neg_grad, base_step)
if improvement >= min_efficiency * rate * base_target_improvement
history.backoff_steps[end] = backoff_steps
step_success = true
break

View File

@ -75,3 +75,12 @@ if success
println(" ", 1 / L[4,k], " sun")
end
end
# test an alternate technique for finding the projected base step from the
# unprojected Hessian
L_alt, success_alt, history_alt = Engine.realize_gram_alt_proj(gram, guess, frozen)
completed_gram_alt = L_alt'*Engine.Q*L_alt
println("\nDifference in result using alternate projection:\n")
display(completed_gram_alt - completed_gram)
println("\nDifference in steps: ", size(history_alt.scaled_loss, 1) - size(history.scaled_loss, 1))
println("Difference in loss: ", history_alt.scaled_loss[end] - history.scaled_loss[end], "\n")

View File

@ -65,3 +65,12 @@ else
end
println("Steps: ", size(history.scaled_loss, 1))
println("Loss: ", history.scaled_loss[end], "\n")
# test an alternate technique for finding the projected base step from the
# unprojected Hessian
L_alt, success_alt, history_alt = Engine.realize_gram_alt_proj(gram, guess, frozen)
completed_gram_alt = L_alt'*Engine.Q*L_alt
println("\nDifference in result using alternate projection:\n")
display(completed_gram_alt - completed_gram)
println("\nDifference in steps: ", size(history_alt.scaled_loss, 1) - size(history.scaled_loss, 1))
println("Difference in loss: ", history_alt.scaled_loss[end] - history.scaled_loss[end], "\n")

View File

@ -94,3 +94,12 @@ if success
radius_ratio = dot(infty, Engine.Q * L[:,5]) / dot(infty, Engine.Q * L[:,6])
println("\nCircumradius / inradius: ", radius_ratio)
end
# test an alternate technique for finding the projected base step from the
# unprojected Hessian
L_alt, success_alt, history_alt = Engine.realize_gram_alt_proj(gram, guess, frozen)
completed_gram_alt = L_alt'*Engine.Q*L_alt
println("\nDifference in result using alternate projection:\n")
display(completed_gram_alt - completed_gram)
println("\nDifference in steps: ", size(history_alt.scaled_loss, 1) - size(history.scaled_loss, 1))
println("Difference in loss: ", history_alt.scaled_loss[end] - history.scaled_loss[end], "\n")

View File

@ -1,3 +0,0 @@
target
dist
Cargo.lock

View File

@ -1,16 +0,0 @@
[package]
name = "rust-benchmark-native"
version = "0.1.0"
authors = ["Aaron"]
edition = "2021"
[dependencies]
cairo-rs = "0.20.1"
gtk = { package = "gtk4", version = "0.9.0" }
nalgebra = "0.33.0"
plotters = "0.3.6"
plotters-cairo = "0.7.0"
[profile.release]
opt-level = "s" # optimize for small code size
debug = true # include debug symbols

View File

@ -1,105 +0,0 @@
use nalgebra::{*, allocator::Allocator};
use std::f64::consts::{PI, E};
/* dynamic matrices */
pub fn rand_eigval_series(dim: usize, time_res: usize) -> Vec<OVector<Complex<f64>, Dyn>> {
// initialize the random matrix
let mut rand_mat = DMatrix::<f64>::from_fn(dim, dim, |j, k| {
let n = j*dim + k;
E*((n*n) as f64) % 2.0 - 1.0
}) * (3.0 / (dim as f64)).sqrt();
// initialize the rotation step
let mut rot_step = DMatrix::<f64>::identity(dim, dim);
let max_freq = 4;
for n in (0..dim).step_by(2) {
let ang = PI * ((n % max_freq) as f64) / (time_res as f64);
let ang_cos = ang.cos();
let ang_sin = ang.sin();
rot_step[(n, n)] = ang_cos;
rot_step[(n+1, n)] = ang_sin;
rot_step[(n, n+1)] = -ang_sin;
rot_step[(n+1, n+1)] = ang_cos;
}
// find the eigenvalues
let mut eigval_series = Vec::<OVector<Complex<f64>, Dyn>>::with_capacity(time_res);
eigval_series.push(rand_mat.complex_eigenvalues());
for _ in 1..time_res {
rand_mat = &rot_step * rand_mat;
eigval_series.push(rand_mat.complex_eigenvalues());
}
eigval_series
}
/* dynamic single float matrices */
/*pub fn rand_eigval_series(dim: usize, time_res: usize) -> Vec<OVector<Complex<f32>, Dyn>> {
// initialize the random matrix
let mut rand_mat = DMatrix::<f32>::from_fn(dim, dim, |j, k| {
let n = j*dim + k;
(E as f32)*((n*n) as f32) % 2.0_f32 - 1.0_f32
}) * (3.0_f32 / (dim as f32)).sqrt();
// initialize the rotation step
let mut rot_step = DMatrix::<f32>::identity(dim, dim);
let max_freq = 4;
for n in (0..dim).step_by(2) {
let ang = (PI as f32) * ((n % max_freq) as f32) / (time_res as f32);
let ang_cos = ang.cos();
let ang_sin = ang.sin();
rot_step[(n, n)] = ang_cos;
rot_step[(n+1, n)] = ang_sin;
rot_step[(n, n+1)] = -ang_sin;
rot_step[(n+1, n+1)] = ang_cos;
}
// find the eigenvalues
let mut eigval_series = Vec::<OVector<Complex<f32>, Dyn>>::with_capacity(time_res);
eigval_series.push(rand_mat.complex_eigenvalues());
for _ in 1..time_res {
rand_mat = &rot_step * rand_mat;
eigval_series.push(rand_mat.complex_eigenvalues());
}
eigval_series
}*/
/* static matrices. should only be used when the dimension is really small */
/*pub fn rand_eigval_series<N>(time_res: usize) -> Vec<OVector<Complex<f64>, N>>
where
N: ToTypenum + DimName + DimSub<U1>,
DefaultAllocator:
Allocator<N> +
Allocator<N, N> +
Allocator<<N as DimSub<U1>>::Output> +
Allocator<N, <N as DimSub<U1>>::Output>
{
// initialize the random matrix
let dim = N::try_to_usize().unwrap();
let mut rand_mat = OMatrix::<f64, N, N>::from_fn(|j, k| {
let n = j*dim + k;
E*((n*n) as f64) % 2.0 - 1.0
}) * (3.0 / (dim as f64)).sqrt();
/*let mut rand_mat = OMatrix::<f64, N, N>::identity();*/
// initialize the rotation step
let mut rot_step = OMatrix::<f64, N, N>::identity();
let max_freq = 4;
for n in (0..dim).step_by(2) {
let ang = PI * ((n % max_freq) as f64) / (time_res as f64);
let ang_cos = ang.cos();
let ang_sin = ang.sin();
rot_step[(n, n)] = ang_cos;
rot_step[(n+1, n)] = ang_sin;
rot_step[(n, n+1)] = -ang_sin;
rot_step[(n+1, n+1)] = ang_cos;
}
// find the eigenvalues
let mut eigval_series = Vec::<OVector<Complex<f64>, N>>::with_capacity(time_res);
eigval_series.push(rand_mat.complex_eigenvalues());
for _ in 1..time_res {
rand_mat = &rot_step * rand_mat;
eigval_series.push(rand_mat.complex_eigenvalues());
}
eigval_series
}*/

View File

@ -1,104 +0,0 @@
// based on Olivier Pelhatre's GTK 3 example, ported to GTK 4
//
// https://github.com/Ouam74/RUST_Real-time_plots_using_GTK-rs_and_Plotters-rs
//
// a self-contained component might draw on the example below, by StackOverflow
// user Nicolas
//
// https://stackoverflow.com/a/76548487
//
// here's a crash course in `plotters`
//
// https://plotters-rs.github.io/book/basic/basic_data_plotting.html
//
extern crate cairo;
use plotters::prelude::*;
use plotters_cairo::CairoBackend;
use gtk::{
glib,
prelude::*,
Adjustment,
Align,
Application,
ApplicationWindow,
Box,
DrawingArea,
Label,
Orientation,
Scale
};
use std::time::Instant;
mod engine;
fn main() -> glib::ExitCode {
let app = Application::builder()
.application_id("org.studioinfinity.rust-benchmark-native")
.build();
app.connect_activate(|app| {
const TIME_RES: usize = 100;
let start_time = Instant::now();
let eigval_series = engine::rand_eigval_series(60, TIME_RES);
let run_time = start_time.elapsed().as_millis();
// application state
let time_step = Adjustment::new(0.0, 0.0, TIME_RES as f64, 1.0, 0.0, 0.0);
// create the window.
let window = ApplicationWindow::builder()
.application(app)
.title("The circular law")
.build();
// create a vertical box
let container = Box::new(Orientation::Vertical, 5);
window.set_child(Some(&container));
// create the run time readout
let run_time_readout = Label::builder()
.margin_top(5)
.margin_start(10)
.halign(Align::Start)
.label(glib::gformat!("{} ms", run_time))
.build();
container.append(&run_time_readout);
// set up the drawing area
let drawing_area = DrawingArea::builder()
.content_width(600)
.content_height(600)
.build();
let time_step_for_draw = time_step.clone();
let draw_eigvals = move |_: &DrawingArea, context: &cairo::Context, width: i32, height: i32| {
let root = CairoBackend::new(&context, (width as u32, height as u32)).unwrap().into_drawing_area();
let _ = root.fill(&BLACK);
const R_DISP: f64 = 1.5;
let mut chart = ChartBuilder::on(&root)
.build_cartesian_2d(-R_DISP..R_DISP, -R_DISP..R_DISP)
.unwrap();
let time_step_val = (time_step_for_draw.value() as usize).min(TIME_RES-1);
let eigval_iter = eigval_series[time_step_val].iter();
let _ = chart.draw_series(
eigval_iter.map(|z| Circle::new((z.re, z.im), 3, WHITE.filled()))
);
let _ = root.present();
};
DrawingAreaExtManual::set_draw_func(&drawing_area, draw_eigvals);
container.append(&drawing_area);
// set up the time step slider
let time_step_scale = Scale::new(Orientation::Horizontal, Some(&time_step));
time_step_scale.connect_value_changed(move |_: &Scale| {
drawing_area.queue_draw();
});
container.append(&time_step_scale);
// show the window
window.present();
});
app.run()
}

View File

@ -1,3 +0,0 @@
target
dist
Cargo.lock

View File

@ -1,9 +0,0 @@
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8"/>
<title>The circular law</title>
<link data-trunk rel="css" href="main.css"/>
</head>
<body></body>
</html>

View File

@ -1,23 +0,0 @@
body {
margin-left: 20px;
margin-top: 20px;
color: #fcfcfc;
background-color: #202020;
}
#app {
display: flex;
flex-direction: column;
width: 600px;
}
canvas {
float: left;
background-color: #020202;
border-radius: 10px;
margin-top: 5px;
}
input {
margin-top: 5px;
}

View File

@ -1,13 +0,0 @@
in profiling, most time is being spent in the `reflect` method:
f64:
sycamore_trial-3d0aca3efee8b5fd.wasm.nalgebra::geometry::reflection::Reflection<T,D,S>::reflect::h7899977a4ba0b1d3
sycamore_trial-3d0aca3efee8b5fd.wasm.nalgebra::geometry::reflection::Reflection<T,D,S>::reflect::hc337c3cb6e3b4061
sycamore_trial-3d0aca3efee8b5fd.wasm.nalgebra::geometry::reflection::Reflection<T,D,S>::reflect_rows::h43d0f6838d0c2833
f32:
sycamore_trial-3d0aca3efee8b5fd.wasm.nalgebra::geometry::reflection::Reflection<T,D,S>::reflect::h0e8ec322f198f847
sycamore_trial-3d0aca3efee8b5fd.wasm.nalgebra::geometry::reflection::Reflection<T,D,S>::reflect::h9928bdd5e72743ea
sycamore_trial-3d0aca3efee8b5fd.wasm.nalgebra::geometry::reflection::Reflection<T,D,S>::reflect_rows::h49f571fd8fc9b0f2
in one test, we spent 4000 ms in "WASM closure", but the enveloping "VoidFunction" takes 1300 ms longer. in another test, though, there's no overhang; the 7000 ms we spent in `rand_eigval_series` accounts for basically the entire load time, and matches the clock timing

View File

@ -1,104 +0,0 @@
use nalgebra::{*, allocator::Allocator};
use std::f64::consts::{PI, E};
/* dynamic matrices */
pub fn rand_eigval_series(dim: usize, time_res: usize) -> Vec<OVector<Complex<f64>, Dyn>> {
// initialize the random matrix
let mut rand_mat = DMatrix::<f64>::from_fn(dim, dim, |j, k| {
let n = j*dim + k;
E*((n*n) as f64) % 2.0 - 1.0
}) * (3.0 / (dim as f64)).sqrt();
// initialize the rotation step
let mut rot_step = DMatrix::<f64>::identity(dim, dim);
let max_freq = 4;
for n in (0..dim).step_by(2) {
let ang = PI * ((n % max_freq) as f64) / (time_res as f64);
let ang_cos = ang.cos();
let ang_sin = ang.sin();
rot_step[(n, n)] = ang_cos;
rot_step[(n+1, n)] = ang_sin;
rot_step[(n, n+1)] = -ang_sin;
rot_step[(n+1, n+1)] = ang_cos;
}
// find the eigenvalues
let mut eigval_series = Vec::<OVector<Complex<f64>, Dyn>>::with_capacity(time_res);
eigval_series.push(rand_mat.complex_eigenvalues());
for _ in 1..time_res {
rand_mat = &rot_step * rand_mat;
eigval_series.push(rand_mat.complex_eigenvalues());
}
eigval_series
}
/* dynamic single float matrices */
/*pub fn rand_eigval_series(dim: usize, time_res: usize) -> Vec<OVector<Complex<f32>, Dyn>> {
// initialize the random matrix
let mut rand_mat = DMatrix::<f32>::from_fn(dim, dim, |j, k| {
let n = j*dim + k;
(E as f32)*((n*n) as f32) % 2.0_f32 - 1.0_f32
}) * (3.0_f32 / (dim as f32)).sqrt();
// initialize the rotation step
let mut rot_step = DMatrix::<f32>::identity(dim, dim);
let max_freq = 4;
for n in (0..dim).step_by(2) {
let ang = (PI as f32) * ((n % max_freq) as f32) / (time_res as f32);
let ang_cos = ang.cos();
let ang_sin = ang.sin();
rot_step[(n, n)] = ang_cos;
rot_step[(n+1, n)] = ang_sin;
rot_step[(n, n+1)] = -ang_sin;
rot_step[(n+1, n+1)] = ang_cos;
}
// find the eigenvalues
let mut eigval_series = Vec::<OVector<Complex<f32>, Dyn>>::with_capacity(time_res);
eigval_series.push(rand_mat.complex_eigenvalues());
for _ in 1..time_res {
rand_mat = &rot_step * rand_mat;
eigval_series.push(rand_mat.complex_eigenvalues());
}
eigval_series
}*/
/* static matrices. should only be used when the dimension is really small */
/*pub fn rand_eigval_series<N>(time_res: usize) -> Vec<OVector<Complex<f64>, N>>
where
N: ToTypenum + DimName + DimSub<U1>,
DefaultAllocator:
Allocator<N> +
Allocator<N, N> +
Allocator<<N as DimSub<U1>>::Output> +
Allocator<N, <N as DimSub<U1>>::Output>
{
// initialize the random matrix
let dim = N::try_to_usize().unwrap();
let mut rand_mat = OMatrix::<f64, N, N>::from_fn(|j, k| {
let n = j*dim + k;
E*((n*n) as f64) % 2.0 - 1.0
}) * (3.0 / (dim as f64)).sqrt();
// initialize the rotation step
let mut rot_step = OMatrix::<f64, N, N>::identity();
let max_freq = 4;
for n in (0..dim).step_by(2) {
let ang = PI * ((n % max_freq) as f64) / (time_res as f64);
let ang_cos = ang.cos();
let ang_sin = ang.sin();
rot_step[(n, n)] = ang_cos;
rot_step[(n+1, n)] = ang_sin;
rot_step[(n, n+1)] = -ang_sin;
rot_step[(n+1, n+1)] = ang_cos;
}
// find the eigenvalues
let mut eigval_series = Vec::<OVector<Complex<f64>, N>>::with_capacity(time_res);
eigval_series.push(rand_mat.complex_eigenvalues());
for _ in 1..time_res {
rand_mat = &rot_step * rand_mat;
eigval_series.push(rand_mat.complex_eigenvalues());
}
eigval_series
}*/

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@ -1,78 +0,0 @@
use std::f64::consts::PI as PI;
use sycamore::{prelude::*, rt::{JsCast, JsValue}};
use web_sys::window;
mod engine;
fn main() {
// set up a config option that forwards panic messages to `console.error`
#[cfg(feature = "console_error_panic_hook")]
console_error_panic_hook::set_once();
sycamore::render(|| {
let time_res: usize = 100;
let time_step = create_signal(0.0);
let run_time_report = create_signal(-1.0);
let display = create_node_ref();
on_mount(move || {
let performance = window().unwrap().performance().unwrap();
let start_time = performance.now();
/*let eigval_series = engine::rand_eigval_series::<U60>(time_res);*/
let eigval_series = engine::rand_eigval_series(60, time_res);
let run_time = performance.now() - start_time;
run_time_report.set(run_time);
let canvas = display
.get::<DomNode>()
.unchecked_into::<web_sys::HtmlCanvasElement>();
let ctx = canvas
.get_context("2d")
.unwrap()
.unwrap()
.dyn_into::<web_sys::CanvasRenderingContext2d>()
.unwrap();
ctx.set_fill_style(&JsValue::from("white"));
create_effect(move || {
// center and normalize the coordinate system
let width = canvas.width() as f64;
let height = canvas.height() as f64;
ctx.set_transform(1.0, 0.0, 0.0, -1.0, 0.5*width, 0.5*height).unwrap();
// clear the previous frame
ctx.clear_rect(-0.5*width, -0.5*width, width, height);
// find the resolution
const R_DISP: f64 = 1.5;
let res = width / (2.0*R_DISP);
// draw the eigenvalues
let eigvals = &eigval_series[time_step.get() as usize];
for n in 0..eigvals.len() {
ctx.begin_path();
ctx.arc(
/* typecast only needed for single float version */
res * f64::from(eigvals[n].re),
res * f64::from(eigvals[n].im),
3.0,
0.0, 2.0*PI
).unwrap();
ctx.fill();
}
});
});
view! {
div(id="app") {
div { (run_time_report.get()) " ms" }
canvas(ref=display, width="600", height="600")
input(
type="range",
max=(time_res - 1).to_string(),
bind:valueAsNumber=time_step
)
}
}
});
}

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@ -1,3 +0,0 @@
target
dist
Cargo.lock

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@ -1,32 +0,0 @@
[package]
name = "sycamore-trial"
version = "0.1.0"
authors = ["Aaron"]
edition = "2021"
[features]
default = ["console_error_panic_hook"]
[dependencies]
nalgebra = "0.33.0"
sycamore = "0.9.0-beta.2"
# The `console_error_panic_hook` crate provides better debugging of panics by
# logging them with `console.error`. This is great for development, but requires
# all the `std::fmt` and `std::panicking` infrastructure, so isn't great for
# code size when deploying.
console_error_panic_hook = { version = "0.1.7", optional = true }
[dependencies.web-sys]
version = "0.3.69"
features = [
'CanvasRenderingContext2d',
'HtmlCanvasElement',
]
[dev-dependencies]
wasm-bindgen-test = "0.3.34"
[profile.release]
# Tell `rustc` to optimize for small code size.
opt-level = "s"

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@ -1,8 +0,0 @@
<!DOCTYPE html>
<html>
<head>
<title>Lattice circle</title>
<link data-trunk rel="css" href="main.css"/>
</head>
<body></body>
</html>

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@ -1,50 +0,0 @@
body {
margin-left: 20px;
margin-top: 20px;
color: #fcfcfc;
background-color: #202020;
}
input {
color: inherit;
background-color: #020202;
border: 1px solid #606060;
min-width: 40px;
border-radius: 4px;
}
input.point-1 {
border-color: #ba5d09;
}
input.point-2 {
border-color: #0e8a06;
}
input.point-3 {
border-color: #8951fb;
}
#data-panel {
float: left;
margin-left: 20px;
display: grid;
grid-template-columns: auto auto;
gap: 10px 10px;
width: 120px;
}
#data-panel > div {
text-align: center;
}
#result-display {
margin-top: 10px;
font-weight: bold;
}
canvas {
float: left;
background-color: #020202;
border-radius: 10px;
}

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@ -1,38 +0,0 @@
use nalgebra::*;
pub struct Circle {
pub center_x: f64,
pub center_y: f64,
pub radius: f64,
}
// construct the circle through the points given by the columns of `points`
pub fn circ_thru(points: Matrix2x3<f64>) -> Option<Circle> {
// build the matrix that maps the circle's coefficient vector to the
// negative of the linear part of the circle's equation, evaluated at the
// given points
let neg_lin_part = stack![2.0*points.transpose(), Vector3::repeat(1.0)];
// find the quadrdatic part of the circle's equation, evaluated at the given
// points
let quad_part = Vector3::from_iterator(
points.column_iter().map(|v| v.dot(&v))
);
// find the circle's coefficient vector, and from there its center and
// radius
match neg_lin_part.lu().solve(&quad_part) {
None => None,
Some(coeffs) => {
let center_x = coeffs[0];
let center_y = coeffs[1];
Some(Circle {
center_x: center_x,
center_y: center_y,
radius: (
coeffs[2] + center_x*center_x + center_y*center_y
).sqrt(),
})
}
}
}

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@ -1,114 +0,0 @@
use nalgebra::Matrix2x3;
use std::f64::consts::PI as PI;
use sycamore::{prelude::*, rt::{JsCast, JsValue}};
mod engine;
fn main() {
// set up a config option that forwards panic messages to `console.error`
#[cfg(feature = "console_error_panic_hook")]
console_error_panic_hook::set_once();
sycamore::render(|| {
let data = [-1.0, 0.0, 0.0, -1.0, 1.0, 0.0].map(|n| create_signal(n));
let display = create_node_ref();
on_mount(move || {
let canvas = display
.get::<DomNode>()
.unchecked_into::<web_sys::HtmlCanvasElement>();
let ctx = canvas
.get_context("2d")
.unwrap()
.unwrap()
.dyn_into::<web_sys::CanvasRenderingContext2d>()
.unwrap();
create_effect(move || {
// center and normalize the coordinate system
let width = canvas.width() as f64;
let height = canvas.height() as f64;
ctx.set_transform(1.0, 0.0, 0.0, -1.0, 0.5*width, 0.5*height).unwrap();
// clear the previous frame
ctx.clear_rect(-0.5*width, -0.5*width, width, height);
// find the resolution
const R_DISP: f64 = 5.0;
let res = width / (2.0*R_DISP);
// set colors
let highlight_style = JsValue::from("white");
let grid_style = JsValue::from("#404040");
let point_fill_styles = ["#ba5d09", "#0e8a06", "#8951fb"];
let point_stroke_styles = ["#f89142", "#58c145", "#c396fc"];
// draw the grid
let r_grid = (R_DISP - 0.01).floor() as i32;
let edge_scr = res * R_DISP;
ctx.set_stroke_style(&grid_style);
for t in -r_grid ..= r_grid {
let t_scr = res * (t as f64);
// draw horizontal grid line
ctx.begin_path();
ctx.move_to(-edge_scr, t_scr);
ctx.line_to(edge_scr, t_scr);
ctx.stroke();
// draw vertical grid line
ctx.begin_path();
ctx.move_to(t_scr, -edge_scr);
ctx.line_to(t_scr, edge_scr);
ctx.stroke();
}
// find and draw the circle through the given points
let data_vals = data.map(|sig| sig.get()).to_vec();
let points = Matrix2x3::from_vec(data_vals);
if let Some(circ) = engine::circ_thru(points) {
ctx.begin_path();
ctx.set_stroke_style(&highlight_style);
ctx.arc(
res * circ.center_x,
res * circ.center_y,
res * circ.radius,
0.0, 2.0*PI
).unwrap();
ctx.stroke();
}
// draw the data points
for n in 0..3 {
ctx.begin_path();
ctx.set_fill_style(&JsValue::from(point_fill_styles[n]));
ctx.set_stroke_style(&JsValue::from(point_stroke_styles[n]));
let ind_x = 2*n;
let ind_y = ind_x + 1;
ctx.arc(
res * data[ind_x].get(),
res * data[ind_y].get(),
3.0,
0.0, 2.0*PI
).unwrap();
ctx.fill();
ctx.stroke();
}
});
});
view! {
canvas(ref=display, width="600", height="600")
div(id="data-panel") {
div { "x" }
div { "y" }
input(type="number", class="point-1", bind:valueAsNumber=data[0])
input(type="number", class="point-1", bind:valueAsNumber=data[1])
input(type="number", class="point-2", bind:valueAsNumber=data[2])
input(type="number", class="point-2", bind:valueAsNumber=data[3])
input(type="number", class="point-3", bind:valueAsNumber=data[4])
input(type="number", class="point-3", bind:valueAsNumber=data[5])
}
}
});
}

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@ -1,2 +0,0 @@
target
sbt.json

View File

@ -1,9 +0,0 @@
enablePlugins(ScalaJSPlugin)
name := "Circular Law"
scalaVersion := "3.4.2"
scalaJSUseMainModuleInitializer := true
libraryDependencies += "com.raquo" %%% "laminar" % "17.0.0"
libraryDependencies += "ai.dragonfly" %%% "slash" % "0.3.1"
libraryDependencies += "org.scala-js" %%% "scalajs-dom" % "2.8.0"

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@ -1,10 +0,0 @@
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>The circular law</title>
<script type="text/javascript" src="./target/scala-3.4.2/circular-law-opt/main.js"></script>
<link rel="stylesheet" href="main.css"/>
</head>
<body></body>
</html>

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@ -1,23 +0,0 @@
body {
margin-left: 20px;
margin-top: 20px;
color: #fcfcfc;
background-color: #202020;
}
#app {
display: flex;
flex-direction: column;
width: 600px;
}
canvas {
float: left;
background-color: #020202;
border-radius: 10px;
margin-top: 5px;
}
input {
margin-top: 5px;
}

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@ -1 +0,0 @@
sbt.version=1.10.1

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@ -1 +0,0 @@
addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.16.0")

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@ -1,99 +0,0 @@
import com.raquo.laminar.api.L.{*, given}
import narr.*
import org.scalajs.dom
import org.scalajs.dom.document
import scala.collection.mutable.ArrayBuffer
import scala.math.{cos, sin}
import slash.matrix.Matrix
import slash.matrix.decomposition.Eigen
object CircularLawApp:
val canvas = canvasTag(widthAttr := 600, heightAttr := 600)
val ctx = canvas.ref.getContext("2d").asInstanceOf[dom.CanvasRenderingContext2D]
val (eigvalSeries, runTimeReport) = randEigvalSeries[60]()
val timeStepState = Var("0")
def draw(timeStep: String): Unit =
// center and normalize the coordinate system
val width = canvas.ref.width
val height = canvas.ref.height
ctx.setTransform(1d, 0d, 0d, -1d, 0.5*width, 0.5*height)
// clear the previous frame
ctx.clearRect(-0.5*width, -0.5*width, width, height)
// find the resolution
val rDisp: Double = 1.5
val res = width / (2*rDisp)
// draw the eigenvalues
val eigvals = eigvalSeries(timeStep.toInt)
for n <- 0 to eigvals(0).length-1 do
ctx.beginPath()
ctx.arc(
res * eigvals(0)(n),
res * eigvals(1)(n),
3d,
0d, 2*math.Pi
)
ctx.fill()
def complexEigenvalues[N <: Int](mat: Matrix[N, N])(using ValueOf[N]): (NArray[Double], NArray[Double]) =
val eigen = Eigen(mat)
(
eigen.realEigenvalues.asInstanceOf[NArray[Double]],
eigen.imaginaryEigenvalues.asInstanceOf[NArray[Double]]
)
def randEigvalSeries[N <: Int]()(using ValueOf[N]): (ArrayBuffer[(NArray[Double], NArray[Double])], String) =
// start timing
val startTime = System.currentTimeMillis()
// initialize the random matrix step
val dim: Int = valueOf[N]
var randMat = new Matrix[N, N](
NArray.tabulate(dim*dim)(k => (math.E*k*k) % 2 - 1)
).times(math.sqrt(3d / dim))
// initialize the rotation step
val timeRes = 100
val maxFreq = 4
val rotStep = Matrix.identity[N, N]
for n <- 0 to dim by 2 do
val ang = math.Pi * (n % maxFreq) / timeRes
val cos_ang = cos(ang)
val sin_ang = sin(ang)
rotStep(n, n) = cos_ang
rotStep(n+1, n) = sin_ang
rotStep(n, n+1) = -sin_ang
rotStep(n+1, n+1) = cos_ang
// find the eigenvalues
val eigvalSeries = ArrayBuffer(complexEigenvalues(randMat))
for _ <- 1 to timeRes-1 do
randMat = rotStep * randMat
eigvalSeries += complexEigenvalues(randMat)
// finish timing
val runTime = System.currentTimeMillis() - startTime
(eigvalSeries, runTime.toString() + " ms")
def main(args: Array[String]): Unit =
ctx.fillStyle = "white"
lazy val app = div(
idAttr := "app",
div(runTimeReport),
canvas,
input(
typ := "range",
maxAttr := (eigvalSeries.length-1).toString,
controlled(
value <-- timeStepState.signal,
onInput.mapToValue --> timeStepState.writer
),
timeStepState.signal --> draw
)
)
renderOnDomContentLoaded(document.body, app)

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@ -1,2 +0,0 @@
target
sbt.json

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@ -1,12 +0,0 @@
enablePlugins(ScalaJSPlugin)
name := "Lattice Circle"
scalaVersion := "3.4.2"
// This is an application with a main method
scalaJSUseMainModuleInitializer := true
libraryDependencies += "com.raquo" %%% "laminar" % "17.0.0"
/*libraryDependencies += "org.scalanlp" %% "breeze" % "2.1.0"*/
libraryDependencies += "ai.dragonfly" %%% "slash" % "0.3.1"
libraryDependencies += "org.scala-js" %%% "scalajs-dom" % "2.8.0"

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@ -1,10 +0,0 @@
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Lattice circle</title>
<script type="text/javascript" src="./target/scala-3.4.2/lattice-circle-fastopt/main.js"></script>
<link rel="stylesheet" href="main.css"/>
</head>
<body></body>
</html>

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@ -1,45 +0,0 @@
body {
margin-left: 20px;
margin-top: 20px;
color: #fcfcfc;
background-color: #202020;
}
input {
color: inherit;
background-color: #020202;
border: 1px solid #606060;
min-width: 40px;
border-radius: 4px;
}
input.point-1 {
border-color: #ba5d09;
}
input.point-2 {
border-color: #0e8a06;
}
input.point-3 {
border-color: #8951fb;
}
#data-panel {
float: left;
margin-left: 20px;
display: grid;
grid-template-columns: auto auto;
gap: 10px 10px;
width: 120px;
}
#data-panel > div {
text-align: center;
}
canvas {
float: left;
background-color: #020202;
border-radius: 10px;
}

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@ -1 +0,0 @@
sbt.version=1.10.1

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@ -1 +0,0 @@
addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.16.0")

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@ -1,160 +0,0 @@
// based on the Laminar example app
//
// https://github.com/raquo/laminar-examples/blob/master/src/main/scala/App.scala
//
// and Li Haoyi's example canvas app
//
// http://www.lihaoyi.com/hands-on-scala-js/#MakingaCanvasApp
//
import com.raquo.laminar.api.L.{*, given}
import narr.*
import org.scalajs.dom
import org.scalajs.dom.document
import scala.math
import slash.matrix.*
class Circle(var centerX: Double, var centerY: Double, var radius: Double)
object LatticeCircleApp:
val canvas = canvasTag(widthAttr := 600, heightAttr := 600)
val ctx = canvas.ref.getContext("2d").asInstanceOf[dom.CanvasRenderingContext2D]
val data = List("-1", "0", "0", "-1", "1", "0").map(Var(_))
def circThru(points: Matrix[3, 2]): Option[Circle] =
// build the matrix that maps the circle's coefficient vector to the
// negative of the linear part of the circle's equation, evaluated at the
// given points
val negLinPart = Matrix.ones[3, 3]
negLinPart.setMatrix(0, 0, points * 2.0)
// find the quadrdatic part of the circle's equation, evaluated at the given
// points
val quadPart = Matrix[3, 1](
NArray.tabulate[Double](3)(
k => points(k, 0)*points(k, 0) + points(k, 1)*points(k, 1)
)
)
// find the circle's coefficient vector, and from there its center and
// radius
try
val coeffs = negLinPart.solve(quadPart)
val centerX = coeffs(0, 0)
val centerY = coeffs(1, 0)
Some(Circle(
centerX,
centerY,
math.sqrt(coeffs(2, 0) + centerX*centerX + centerY*centerY)
))
catch
_ => return None
def draw(): Unit =
// center and normalize the coordinate system
val width = canvas.ref.width
val height = canvas.ref.height
ctx.setTransform(1.0, 0.0, 0.0, -1.0, 0.5*width, 0.5*height)
// clear the previous frame
ctx.clearRect(-0.5*width, -0.5*width, width, height)
// find the resolution
val rDisp = 5.0
val res = width / (2.0*rDisp)
// set colors
val highlightStyle = "white"
val gridStyle = "#404040"
val pointFillStyles = List("#ba5d09", "#0e8a06", "#8951fb")
val pointStrokeStyles = List("#f89142", "#58c145", "#c396fc")
// draw the grid
val rGrid = (rDisp - 0.01).floor.toInt
val edgeScr = res * rDisp
ctx.strokeStyle = gridStyle
for t <- -rGrid to rGrid do
val tScr = res * t
// draw horizontal grid line
ctx.beginPath();
ctx.moveTo(-edgeScr, tScr)
ctx.lineTo(edgeScr, tScr)
ctx.stroke()
// draw vertical grid line
ctx.beginPath();
ctx.moveTo(tScr, -edgeScr)
ctx.lineTo(tScr, edgeScr)
ctx.stroke()
// find and draw the circle through the given points
val dataNow = NArray.tabulate(6)(n =>
try
data(n).signal.now().toDouble
catch
_ => Double.NaN
)
if dataNow.forall(t => t == t.floor) then
// all of the coordinates are integer and non-NaN
val points = Matrix[3, 2](dataNow)
circThru(points) match
case Some(circ) =>
ctx.beginPath()
ctx.strokeStyle = highlightStyle
ctx.arc(
res * circ.centerX,
res * circ.centerY,
res * circ.radius,
0.0, 2.0*math.Pi
)
ctx.stroke()
case None =>
// draw the data points
for n <- 0 to 2 do
val indX = 2*n
val indY = indX + 1
if
dataNow(indX) == dataNow(indX).floor &&
dataNow(indY) == dataNow(indY).floor
then
ctx.beginPath()
ctx.fillStyle = pointFillStyles(n)
ctx.strokeStyle = pointStrokeStyles(n)
ctx.arc(
res * dataNow(indX),
res * dataNow(indY),
3.0,
0.0, 2.0*math.Pi
)
ctx.fill()
ctx.stroke()
def coordInput(n: Int): Input =
input(
typ := "number",
cls := s"point-${(1.0 + 0.5*n).floor.toInt}",
controlled(
value <-- data(n).signal,
onInput.mapToValue --> data(n).writer
),
data(n).signal --> { _ => draw() }
)
def main(args: Array[String]): Unit =
lazy val app = div(
canvas,
div(
idAttr := "data-panel",
div("x"),
div("y"),
coordInput(0),
coordInput(1),
coordInput(2),
coordInput(3),
coordInput(4),
coordInput(5)
)
)
renderOnDomContentLoaded(document.body, app)

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@ -2,28 +2,29 @@
(proposed by Alex Kontorovich as a practical system for doing 3D geometric calculations)
These coordinates are of form $I=(c, r, x, y, z)$ where we think of $c$ as the co-radius, $r$ as the radius, and $x, y, z$ as the "Euclidean" part, which we abbreviate $E_I$. There is an underlying basic quadratic form $Q(I_1,I_2) = (c_1r_2+c_2r_1)/2 - x_1x_2 -y_1y_2-z_1z_2$ which aids in calculation/verification of coordinates in this representation. We have:
These coordinates are of form $I=(c, b, x, y, z)$ where we think of $c$ as the co-radius, $b$ as the "bend" (reciprocal radius), and $x, y, z$ as the "Euclidean" part, which we abbreviate $E_I$. There is an underlying basic quadratic form $Q(I_1,I_2) = (c_1b_2+c_2b_1)/2 - x_1x_2 -y_1y_2-z_1z_2$ which aids in calculation/verification of coordinates in this representation. We have:
| Entity or Relationship | Representation | Comments/questions |
| ------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Sphere s with radius r>0 centered on P = (x,y,z) | $I_s = (1/c, 1/r, x/r, y/r, z/r)$ satisfying $Q(I_s,I_s) = -1$, i.e., $c = r/(\|P\|^2 - r^2)$. | Can also write $I_s = (\|P\|^2/r - r, 1/r, x/r. y/r, z/r)$—so there is no trouble if $\|E_{I_s}\| = r$, just get first coordinate to be 0. |
| Plane p with unit normal (x,y,z) through the point s(x,y,z) | $I_p = (-2s, 0, -x, -y, -z)$ | Note $Q(I_p, I_p)$ is still 1. |
| Point P with Euclidean coordinates (x,y,z) | $I_P = (\|P\|^2, 1, x, y, z)$ | Note $Q(I_P,I_P) = 0$.  Because of this we might choose  some other scaling of the inversive coordinates, say $(\||P\||,1/\||P\||,x/\||P\||,y/\||P\||,z/\||P\||)$ instead, but that fails at the origin, and likely won't have some of the other nice properties listed below.  Note that scaling just the co-radius by $s$ and the radius by $1/s$ (which still preserves $Q=0$) dilates by a factor of $s$ about the origin, so that $(\|P\|, \|P\|, x, y, z)$, which might look symmetric, would actually have to represent the Euclidean point $(x/\||P\||, y/\||P\||, z/\||P\||)$ . |
| ∞, the "point at infinity" | $I_\infty = (1,0,0,0,0)$ | The only solution to $Q(I,I) = 0$ not covered by the above case. |
| P lies on sphere or plane given by I | $Q(I_P, I) = 0$ | |
| Sphere/planes represented by I and J are tangent | If $I$ and $J$ have the same orientation where they touch, $Q(I,J) = -1$. If they have opposing orientations, $Q(I,J) = 1$. | For example, the $xy$ plane with normal $-e_z$, represented by $(0,0,0,0,1)$, is tangent with matching orientation to the unit sphere centered at $(0,0,1)$ with outward normals, represented by $(0,1,0,0,1)$. Accordingly, their $Q$-product is 1. |
| Sphere/planes represented by I and J intersect (respectively, don't intersect) | $\|Q(I,J)\| < (\text{resp. }>)\; 1$ | Follows from the angle formula, at least conceptually. |
| P is center of sphere represented by I | Well, $Q(I_P, I)$ comes out to be $(\|P\|^2/r - r + \|P\|^2/r)/2 - \|P\|^2/r$ or just $-r/2$ . | Is it if and only if ?   No this probably doesn't work because center is not conformal quantity. |
| Distance between P and R is d | $Q(I_P, I_R) = d^2/2$ | |
| Distance between P and sphere/plane rep by I | | In the very simple case of a plane $I$ rep'd by $(2s, 0, x, y, z)$ and a point $P$ that lies on its perpendicular through the origin, rep'd by $(r^2, 1, rx, ry, rz)$ we get $Q(I, I_p) = s-r$, which is indeed the signed distance between $I$ and $P$. Not sure if this generalizes to other combinations? |
| Distance between sphere/planes rep by I and J | Note that for any two Euclidean-concentric spheres rep by $I$ and $J$ with radius $r$ and $s,$ $Q(I,J) = -\frac12\left(\frac rs  + \frac sr\right)$ depends only on the ratio of $r$ and $s$. So this can't give something that determines the Euclidean distance between the two spheres, which presumably grows as the two spheres are blown up proportionally. For another example, for any two parallel planes, $Q(I,J) = \pm1$. | Alex had said: $Q(I,J)=\cosh(d/2)^2$ maybe where d is distance in usual hyperbolic metric. Or maybe $\cosh(d)$. That may be right depending on what's meant by the hyperbolic metric there, but it seems like it won't determine a reasonable Euclidean distance between planes, which should differ between different pairs of parallel planes. |
| Sphere centered on P through R | | Probably just calculate distance etc. |
| Plane rep'd by I goes through center of sphere rep'd by J | I think this is equivalent to the plane being perpendicular to the sphere, i.e. $Q(I,J) = 0$. | |
| Dihedral angle between planes (or spheres?) rep by I and J | $\theta = \arccos(Q(I,J))$ | Aaron Fenyes points out: The angle between spheres in $S^3$ matches the angle between the planes they bound in $R^{(1,4)}$, which matches the angle between the spacelike vectors perpendicular to those planes. So we should have $Q(I,J) = \cos(\theta)$. Note that when the spheres do not intersect, we can interpret this as the "imaginary angle" between them, via $\cosh(t) = \cos(it)$. |
| R, P, S are collinear | Maybe just cross product of two differences is 0. Or, $R,P,S,\infty$ lie on a circle, or equivalently, $I_R,I_P,I_S,I_\infty$ span a plane (rather than a three-space). | $R,P,S$ lying on a line isn't a conformal property, but $R,P,S,\infty$ lying on a circle is. |
| Plane through noncollinear R, P, S | Should be, just solve $Q(I, I_R) = 0$ etc. | |
| circle | Maybe concentric sphere and the containing plane? Note it is easy to constrain the relationship between those two: they must be perpendicular. | Defn: circle is intersection of two spheres. That does cover lines. But you lose the canonicalness |
| line | Maybe two perpendicular containing planes? Maybe the plane perpendicular to the line and through origin, together with the point of the line on that plane? Or maybe just as a bag of collinear points? | The first is the limiting case of the possible circle rep, but it is not canonical. The second appears to be canonical, but I don't see a circle rep that corresponds to it. |
| Entity or Relationship | Representation | Comments/questions |
| ---------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Sphere $s$ with radius $r>0$ centered on $P = (x,y,z)$ | $I_s = (\frac1{c}, \frac1{r}, \frac{x}{r}, \frac{y}{r}, \frac{z}{r})$ satisfying $Q(I_s,I_s) = -1,$ i.e., $c = r/(\|P\|^2 - r^2)$. | Note that $1/c = \|P\|^2/r - r$, so there is no trouble if $\|P\| = r$; we just get first coordinate to be 0. Using the point representation $I_P$ from below, let's orient the sphere so that its normals point into the "positive side," where $Q(I_P, I_s) > 0$. The vector $I_s$ then represents a sphere with outward normals, while $-I_s$ represents one with inward normals. |
| Plane $p$ with unit normal $(x,y,z)$ through the (Euclidean) point $(sx,sy,sz)$ | $I_p = (-2s, 0, -x, -y, -z)$ | Note that $Q(I_p, I_p)$ is still $-1$. We orient planes using the same convention we use for spheres. For example, $(-2, 0, -1/\sqrt3, -1/\sqrt3, -1/\sqrt3)$ and $(2, 0, 1/\sqrt3, 1/\sqrt3, 1/\sqrt3)$ represent planes that coincide in space, which have their normals pointing away from and toward the origin, respectively. Note that the ray from $(sx, sy, sz) \in p$ in direction $(-x, -y, -z)$ is the ray perpendicular to the plane through the origin; since $(-x, -y, -z)$ is a unit vector, $(sx, sy, sz)$ and hence $p$ is at distance $s$ from the origin. These coordinates are essentially the limit of a sphere's coordinates as its radius goes to infinity, or equivalently, as its bend goes to 0. |
| Point $P$ with Euclidean coordinates $(x,y,z)$ | $I_P = (\|P\|^2, 1, x, y, z)$ | Note $Q(I_P,I_P) = 0$. This gives us the freedom to choose a different normalization. For example, we could scale the representation shown here by $(\|P\|^2+1)^{-1}$, putting it on the sphere where the light cone intersects the plane where the first two coordinates sum to $1$. |
| ∞, the "point at infinity" | $I_\infty = (1,0,0,0,0)$ | The only solution to $Q(I,I) = 0$ not covered by (some normalization of) the above case. |
| Point $P$ lies on sphere or plane given by $I$ | $Q(I_P, I) = 0$ | Actually also works if $I$ is the coordinates of a point, in which case "lies on" simply means "coincides with". |
| Sphere/planes represented by $I$ and $J$ are tangent | If $I$ and $J$ have the same orientation where they touch, $Q(I,J) = -1$. If they have opposing orientations, $Q(I,J) = 1$. | For example, the $xy$ plane with normal $-e_z$, represented by $(0,0,0,0,1)$, is tangent with matching orientation to the unit sphere centered at $(0,0,1)$ with outward normals, represented by $(0,1,0,0,1).$ Accordingly, their $Q$ - product is $-1$. |
| Sphere/planes represented by $I$ and $J$ intersect (respectively, don't intersect) | $\lvert Q(I,J)\rvert \le (\text{resp. }>)\; 1$ | Follows from the angle formula and the tangency condition, at least conceptually. One subtlety: parallel planes have $Q$ - product $\pm 1$, because they intersect at infinity (and in fact, are "tangent" there)! |
| $P$ is center of sphere rep'd by $I$ | $Q(I, I_P) = -r/2$, where $1/r = 2Q(I_\infty, I)$ is the signed bend of the sphere, and $I_P$ is normalized in the standard way, which is to set $Q(I_\infty, I_P) = 1/2$ | This relationship is equivalent to both of the following. (1) The point $P$ has signed distance $-r$ from the sphere. (2) Inversion across the sphere maps $\infty$ to $P$. |
| Distance between points $P$ and $R$ is $d$ | $Q(I_P, I_R) = d^2/2$ | If $P$ and $R$ are represented by non-normalized vectors $V_P$ and $V_R$, the relation becomes $Q(V_P, V_R) = 2\,Q(V_P, I_\infty)\,Q(V_R, I_\infty)\,d^2$. This version of the relation makes it easier to see why $d$ goes to infinity as $P$ or $R$ approaches the point at infinity. |
| Signed distance between point rep'd by $V$ and sphere/plane rep'd by $I$ is $d$ | In general, $\frac{Q(I, V)}{2Q(I_\infty, V)} = Q(I_\infty, I)\,d^2 + d$. When $V$ is normalized in the usual way, this simplifies to $Q(I, V) = d^2/r + d$ for a sphere of radius $r$, and to $Q(I, V) = d$ for a plane. | We can use a Euclidean motion, represented linearly by a Lorentz transformation that fixes $I_\infty$, to put the point on the $z$ axis and put the nearest point on the sphere/plane at the origin with its normal pointing in the positive $z$ direction. Then the sphere/plane is represented by $I = (0, 1/r, 0, 0, -1)$, and the point can be represented by any multiple of $I_P = (d^2, 1, 0, 0, d)$, giving $Q(I, I_P) = d^2/2r + d.$ We turn this into a general expression by writing it in terms of Lorentz-invariant quantities and making it independent of the normalization of $I_P$. |
| Distance between sphere/planes rep by $I$ and $J$ | Note that for any two Euclidean-concentric spheres rep by $I$ and $J$ with radius $r$ and $s,$ $Q(I,J) = -\frac12\left(\frac rs + \frac sr\right)$ depends only on the ratio of $r$ and $s$. So this can't give something that determines the Euclidean distance between the two spheres, which presumably grows as the two spheres are blown up proportionally. For another example, for any two parallel planes, $Q(I,J) = \pm1$. | Alex had said: $Q(I,J)=\cosh(d/2)^2$ maybe where d is distance in usual hyperbolic metric. Or maybe $\cosh(d)$. That may be right depending on what's meant by the hyperbolic metric there, but it seems like it won't determine a reasonable Euclidean distance between planes, which should differ between different pairs of parallel planes. |
| Sphere centered on point $P$ through point $R$ | | Probably just calculate distance etc. |
| Plane rep'd by $I$ goes through center of sphere rep'd by $J$ | This is equivalent to the plane being perpendicular to the sphere: that is, $Q(I, J) = 0$. | |
| Dihedral angle between planes or spheres rep by $I$ and $J$ | $\theta = \arccos(Q(I,J))$ | Aaron Fenyes points out: The angle between spheres in $S^3$ matches the angle between the planes they bound in $R^{(1,4)}$, which matches the angle between the spacelike vectors perpendicular to those planes. So we should have $Q(I,J) = \cos(\theta)$. Note that when the spheres do not intersect, we can interpret this as the "imaginary angle" between them, via $\cosh(t) = \cos(it)$. |
| Points $R, P, S$ are collinear | Maybe just cross product of two differences is 0. Or, $R,P,S,\infty$ lie on a circle, or equivalently, $I_R,I_P,I_S,I_\infty$ span a plane (rather than a three-space). Or we can add two planes constrained to be perpendicular with one constrained to contain the origin, and all three points constrained to lie on both. But that's a lot of auxiliary entities and constraints... | $R,P,S$ lying on a line isn't a conformal property, but $R,P,S,\infty$ lying on a circle is. |
| Plane through noncollinear $R, P, S$ | Should be, just solve $Q(I, I_R) = 0$ etc. | |
| circle | Maybe concentric sphere and the containing plane? Note it is easy to constrain the relationship between those two: they must be perpendicular. | Defn: circle is intersection of two spheres. That does cover lines. But you lose the canonicalness |
| line | Maybe two perpendicular containing planes? Maybe the plane perpendicular to the line and through origin, together with the point of the line on that plane? Or maybe just as a bag of collinear points? | The first is the limiting case of the possible circle rep, but it is not canonical. However, there is a distinguished "standard" choice we could make: always choose one plane to contain the origin and the line, and the other to be the perpendicular plane containing the line. That choice or Plücker coordinates might be the best we can do. If we use the standardized perpendicular planes choice, then adding a line would be equivalent to adding two planes and the two constraints that one contains the origin and the other is perpendicular to it. That doesn't seem so bad. The second convention (perpendicular plane through the origin and a point on it) appears to be canonical, but there doesn't seem to be a circle representation that tends to it in the limit. |
| Inversion of entity represented by $v$ across sphere $s$, rep'd by $I_s$ | $v \mapsto v + 2Q(I_s, v)\,I_s$ | This is just an educated guess, but its behavior is consistent with inversion in at least two ways. (1) It fixes points on $s$ and spheres perpendicular to $s$. (2) It preserves dihedral angles with $s$. |
The unification of spheres/planes is indeed attractive for a project like Dyna3. The relationship between this representation and Geometric Algebras is a bit murky; likely it somehow fits under the Geometric Algebra umbrella.
@ -40,3 +41,25 @@ I will have to work out formulas for the Euclidean distance between two entities
In this vein, it seems as though if J1 and J2 are the reps of two points, then Q(J1,J2) = d^2/2. So then the sphere centered at J1 through J2 is (J1-(2Q(J1,J2),0,0,0,0))/sqrt(2Q(J1,J2)). Ugh has a sqrt in it. Similarly for sphere centered at J3 through J2, (J3-(2Q(J3,J2),0000))/sqrt(2Q(J3,J2)). J1,J2,J3 are collinear if these spheres are tangent, i.e. if those vectors have Q-inner-product 1, which is to say Q(J1,J3) - Q(J1,J2) - Q(J3,J2) = 2sqrt(Q(J1,J2)Q(J2,J3)). But maybe that's not the simplest way of putting it. After all, we can just say that the cross-product of the two differences is 0; that has no square roots in it.
One conceivable way to canonicalize lines is to use the *perpendicular* plane that goes through the origin, that's uniquely defined, and anyway just amounts to I = (0,0,d) where d is the ordinary direction vector of the line; and a point J in that plane that the line goes through, which just amounts to J=(r^2,1,E) with Q(I,J) = 0, i.e. E\dot d = 0. It's also the point on the line closest to the origin. The reason that we don't usually use that point as the companion to the direction vector is that the resulting set of six coordinates is not homogeneous. But here that's not an issue, since we have our standard point coordinates and plane coordinates; and for a plane through the origin, only two of the direction coordinates are really free, and then we have the one dot-product relation, so only two of the point coordinates are really free, giving us the correct dimensionality of 4 for the set of lines. So in some sense this says that we could take naively as coordinates for a line the projection of the unit direction vector to the xy plane and the projection of the line's closest point to the origin to the xy plane. That doesn't seem to have any weird gimbal locks or discontinuities or anything. And with these coordinates, you can test if the point E=x,y,z is on the line (dx,dy,cx,cy) by extending (dx,dy) to d via dz = sqrt(1-dx^2 - dy^2), extending (cx,cy) to c by determining cz via d\dot c = 0, and then checking if d\cross(E-c) = 0. And you can see if two lines are parallel just by checking if they have the same direction vector, and if not, you can see if they are coplanar by projecting both of their closest points perpendicularly onto the line in the direction of the cross product of their directions, and if the projections match they are coplanar.
#### Engine Conventions
The coordinate conventions used in the engine are different from the ones used in these notes. Marking the engine vectors and coordinates with $'$, we have
$$I' = (x', y', z', b', c'),$$
where
$$
\begin{align*}
x' & = x & b' & = b/2 \\
y' & = y & c' & = c/2. \\
z' & = z
\end{align*}
$$
The engine uses the quadratic form $Q' = -Q$, which is expressed in engine coordinates as
$$Q'(I'_1, I'_2) = x'_1 x'_2 + y'_1 y'_2 + z'_1 z'_2 - 2(b'_1c'_2 + c'_1 b'_2).$$
In the `engine` module, the matrix of $Q'$ is encoded in the lazy static variable `Q`.
In the engine's coordinate conventions, a sphere with radius $r > 0$ centered on $P = (P_x, P_y, P_z)$ is represented by the vector
$$I'_s = \left(\frac{P_x}{r}, \frac{P_y}{r}, \frac{P_z}{r}, \frac1{2r}, \frac{\|P\|^2 - r^2}{2r}\right),$$
which has the normalization $Q'(I'_s, I'_s) = 1$. The point $P$ is represented by the vector
$$I'_P = \left(P_x, P_y, P_z, \frac{1}{2}, \frac{\|P\|^2}{2}\right).$$
In the `engine` module, these formulas are encoded in the `sphere` and `point` functions.