Generalize constraints to observables (#48)

Unifies the interface elements for measuring and constraining real-valued observables, as proposed in issue #47. The resulting combination is called a "Regulator," at least in the code. They are presented as text inputs in the table view. When a Regulatore is in measurement mode (has no "set point"), the text field displays its value. Entering a desired value into the text field creates a set point, and then the Regulator acts to (attempt to) constrain the value. Setting the desired value to the empty string switches the observable back to measurement mode. If you enter a desired value that can't be parsed as a floating point number, the regulator input is flagged as invalid and it has no effect on the state of the regulator. The set point can in this case be restored to its previous value (or to no set point if that was its prior state) by pressing the "Esc" key.

Co-authored-by: Aaron Fenyes <aaron.fenyes@fareycircles.ooo>
Co-authored-by: glen <glen@studioinfinity.org>
Reviewed-on: glen/dyna3#48
Co-authored-by: Vectornaut <vectornaut@nobody@nowhere.net>
Co-committed-by: Vectornaut <vectornaut@nobody@nowhere.net>

app-proto/Cargo.toml

@@ -13,6 +13,7 @@ itertools = "0.13.0"
 js-sys = "0.3.70"
 lazy_static = "1.5.0"
 nalgebra = "0.33.0"
+readonly = "0.2.12"
 rustc-hash = "2.0.0"
 slab = "0.4.9"
 sycamore = "0.9.0-beta.3"

app-proto/main.css

@@ -3,7 +3,8 @@
   --text-bright: white;
   --text-invalid: #f58fc2; /* bright pink */
   --border: #555; /* light gray */
-  --border-focus: #aaa; /* bright gray */
+  --border-focus-dark: #aaa; /* bright gray */
+  --border-focus-light: white;
   --border-invalid: #70495c; /* dusky pink */
   --selection-highlight: #444; /* medium gray */
   --page-background: #222; /* dark gray */
@@ -23,7 +24,7 @@ body {
   display: flex;
   flex-direction: column;
   float: left;
-  width: 450px;
+  width: 500px;
   height: 100vh;
   margin: 0px;
   padding: 0px;
@@ -77,12 +78,12 @@ summary.selected {
   background-color: var(--selection-highlight);
 }
 
-summary > div, .constraint {
+summary > div, .regulator {
   padding-top: 4px;
   padding-bottom: 4px;
 }
 
-.element, .constraint {
+.element, .regulator {
   display: flex;
   flex-grow: 1;
   padding-left: 8px;
@@ -107,7 +108,7 @@ details[open]:has(li) .element-switch::after {
   flex-grow: 1;
 }
 
-.constraint-label {
+.regulator-label {
   flex-grow: 1;
 }
 
@@ -123,26 +124,34 @@ details[open]:has(li) .element-switch::after {
   width: 56px;
 }
 
-.constraint {
+.regulator {
   font-style: italic;
 }
 
-.constraint.invalid {
+.regulator-type {
-  color: var(--text-invalid);
+  padding: 2px 8px 0px 8px;
+  font-size: 10pt;
 }
 
-.constraint > input[type=checkbox] {
+.regulator-input {
-  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] {
+.regulator-input::placeholder {
+  color: inherit;
+  opacity: 54%;
+  font-style: italic;
+}
+
+.regulator-input.constraint {
+  background-color: var(--display-background);
+}
+
+.regulator-input.invalid {
+  color: var(--text-invalid);
   border-color: var(--border-invalid);
 }
 
@@ -154,7 +163,7 @@ details[open]:has(li) .element-switch::after {
   font-style: normal;
 }
 
-.invalid > .status::after, details:has(.invalid):not([open]) .status::after {
+.regulator-input.invalid + .status::after, details:has(.invalid):not([open]) .status::after {
   content: '⚠';
   color: var(--text-invalid);
 }
@@ -171,5 +180,11 @@ canvas {
 }
 
 canvas:focus {
-  border-color: var(--border-focus);
+  border-color: var(--border-focus-dark);
+  outline: none;
+}
+
+input:focus {
+  border-color: var(--border-focus-light);
+  outline: none;
 }

app-proto/src/add_remove.rs

@@ -1,7 +1,11 @@
 use sycamore::prelude::*;
 use web_sys::{console, wasm_bindgen::JsValue};
 
-use crate::{engine, AppState, assembly::{Assembly, Constraint, Element}};
+use crate::{
+    engine,
+    AppState,
+    assembly::{Assembly, Element}
+};
 
 /* DEBUG */
 // load an example assembly for testing. this code will be removed once we've
@@ -190,44 +194,8 @@ pub fn AddRemove() -> View {
                             (subject_vec[0].clone(), subject_vec[1].clone())
                         }
                     );
-                    let lorentz_prod = create_signal(0.0);
+                    state.assembly.insert_new_regulator(subjects);
-                    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

app-proto/src/assembly.rs

@@ -5,11 +5,14 @@ use std::{collections::BTreeSet, sync::atomic::{AtomicU64, Ordering}};
 use sycamore::prelude::*;
 use web_sys::{console, wasm_bindgen::JsValue}; /* DEBUG */
 
-use crate::engine::{realize_gram, local_unif_to_std, ConfigSubspace, PartialMatrix};
+use crate::{
+    engine::{Q, local_unif_to_std, realize_gram, ConfigSubspace, PartialMatrix},
+    specified::SpecifiedValue
+};
 
-// the types of the keys we use to access an assembly's elements and constraints
+// the types of the keys we use to access an assembly's elements and regulators
 pub type ElementKey = usize;
-pub type ConstraintKey = usize;
+pub type RegulatorKey = usize;
 
 pub type ElementColor = [f32; 3];
 
@@ -26,7 +29,10 @@ pub struct Element {
     pub label: String,
     pub color: ElementColor,
     pub representation: Signal<DVector<f64>>,
-    pub constraints: Signal<BTreeSet<ConstraintKey>>,
+    
+    // All regulators with this element as a subject. The assembly owning
+    // this element is responsible for keeping this set up to date.
+    pub regulators: Signal<BTreeSet<RegulatorKey>>,
     
     // a serial number, assigned by `Element::new`, that uniquely identifies
     // each element
@@ -61,7 +67,7 @@ impl Element {
             label: label,
             color: color,
             representation: create_signal(representation),
-            constraints: create_signal(BTreeSet::default()),
+            regulators: create_signal(BTreeSet::default()),
             serial: serial,
             column_index: None
         }
@@ -111,13 +117,11 @@ impl Element {
     }
 }
 
-#[derive(Clone)]
+#[derive(Clone, Copy)]
-pub struct Constraint {
+pub struct Regulator {
     pub subjects: (ElementKey, ElementKey),
-    pub lorentz_prod: Signal<f64>,
+    pub measurement: ReadSignal<f64>,
-    pub lorentz_prod_text: Signal<String>,
+    pub set_point: Signal<SpecifiedValue>
-    pub lorentz_prod_valid: Signal<bool>,
-    pub active: Signal<bool>
 }
 
 // the velocity is expressed in uniform coordinates
@@ -131,9 +135,9 @@ type AssemblyMotion<'a> = Vec<ElementMotion<'a>>;
 // a complete, view-independent description of an assembly
 #[derive(Clone)]
 pub struct Assembly {
-    // elements and constraints
+    // elements and regulators
     pub elements: Signal<Slab<Element>>,
-    pub constraints: Signal<Slab<Constraint>>,
+    pub regulators: Signal<Slab<Regulator>>,
     
     // solution variety tangent space. the basis vectors are stored in
     // configuration matrix format, ordered according to the elements' column
@@ -155,13 +159,13 @@ impl Assembly {
     pub fn new() -> Assembly {
         Assembly {
             elements: create_signal(Slab::new()),
-            constraints: create_signal(Slab::new()),
+            regulators: create_signal(Slab::new()),
             tangent: create_signal(ConfigSubspace::zero(0)),
             elements_by_id: create_signal(FxHashMap::default())
         }
     }
     
-    // --- inserting elements and constraints ---
+    // --- inserting elements and regulators ---
     
     // insert an element into the assembly without checking whether we already
     // have an element with the same identifier. any element that does have the
@@ -204,14 +208,61 @@ impl Assembly {
         );
     }
     
-    pub fn insert_constraint(&self, constraint: Constraint) {
+    fn insert_regulator(&self, regulator: Regulator) {
-        let subjects = constraint.subjects;
+        let subjects = regulator.subjects;
-        let key = self.constraints.update(|csts| csts.insert(constraint));
+        let key = self.regulators.update(|regs| regs.insert(regulator));
-        let subject_constraints = self.elements.with(
+        let subject_regulators = self.elements.with(
-            |elts| (elts[subjects.0].constraints, elts[subjects.1].constraints)
+            |elts| (elts[subjects.0].regulators, elts[subjects.1].regulators)
         );
-        subject_constraints.0.update(|csts| csts.insert(key));
+        subject_regulators.0.update(|regs| regs.insert(key));
-        subject_constraints.1.update(|csts| csts.insert(key));
+        subject_regulators.1.update(|regs| regs.insert(key));
+    }
+    
+    pub fn insert_new_regulator(self, subjects: (ElementKey, ElementKey)) {
+        // create and insert a new regulator
+        let measurement = self.elements.map(
+            move |elts| {
+                let reps = (
+                    elts[subjects.0].representation.get_clone(),
+                    elts[subjects.1].representation.get_clone()
+                );
+                reps.0.dot(&(&*Q * reps.1))
+            }
+        );
+        let set_point = create_signal(SpecifiedValue::from_empty_spec());
+        self.insert_regulator(Regulator {
+            subjects: subjects,
+            measurement: measurement,
+            set_point: set_point
+        });
+        
+        /* DEBUG */
+        // print an updated list of regulators
+        console::log_1(&JsValue::from("Regulators:"));
+        self.regulators.with(|regs| {
+            for (_, reg) in regs.into_iter() {
+                console::log_5(
+                    &JsValue::from(" "),
+                    &JsValue::from(reg.subjects.0),
+                    &JsValue::from(reg.subjects.1),
+                    &JsValue::from(":"),
+                    &reg.set_point.with_untracked(
+                        |set_pt| JsValue::from(set_pt.spec.as_str())
+                    )
+                );
+            }
+        });
+        
+        // update the realization when the regulator becomes a constraint, or is
+        // edited while acting as a constraint
+        create_effect(move || {
+            console::log_1(&JsValue::from(
+                format!("Updated constraint with subjects ({}, {})", subjects.0, subjects.1)
+            ));
+            if set_point.with(|set_pt| set_pt.is_present()) {
+                self.realize();
+            }
+        });
     }
     
     // --- realization ---
@@ -228,14 +279,16 @@ impl Assembly {
         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| {
+            self.regulators.with_untracked(|regs| {
-                for (_, cst) in csts {
+                for (_, reg) in regs {
-                    if cst.active.get_untracked() && cst.lorentz_prod_valid.get_untracked() {
+                    reg.set_point.with_untracked(|set_pt| {
-                        let subjects = cst.subjects;
+                        if let Some(val) = set_pt.value {
+                            let subjects = reg.subjects;
                             let row = elts[subjects.0].column_index.unwrap();
                             let col = elts[subjects.1].column_index.unwrap();
-                        gram_to_be.push_sym(row, col, cst.lorentz_prod.get_untracked());
+                            gram_to_be.push_sym(row, col, val);
                         }
+                    });
                 }
             });
             

app-proto/src/main.rs

@@ -3,6 +3,7 @@ mod assembly;
 mod display;
 mod engine;
 mod outline;
+mod specified;
 
 use rustc_hash::FxHashSet;
 use sycamore::prelude::*;

app-proto/src/outline.rs

@@ -1,56 +1,97 @@
 use itertools::Itertools;
 use sycamore::prelude::*;
 use web_sys::{
-    Event,
-    HtmlInputElement,
     KeyboardEvent,
     MouseEvent,
     wasm_bindgen::JsCast
 };
 
-use crate::{AppState, assembly, assembly::{Constraint, ConstraintKey, ElementKey}};
+use crate::{
+    AppState,
+    assembly,
+    assembly::{ElementKey, Regulator, RegulatorKey},
+    specified::SpecifiedValue
+};
 
-// an editable view of the Lorentz product representing a constraint
+// an editable view of a regulator
 #[component(inline_props)]
-fn LorentzProductInput(constraint: Constraint) -> View {
+fn RegulatorInput(regulator: Regulator) -> View {
+    let valid = create_signal(true);
+    let value = create_signal(
+        regulator.set_point.with_untracked(|set_pt| set_pt.spec.clone())
+    );
+    
+    // this closure resets the input value to the regulator's set point
+    // specification
+    let reset_value = move || {
+        batch(|| {
+            valid.set(true);
+            value.set(regulator.set_point.with(|set_pt| set_pt.spec.clone()));
+        })
+    };
+    
+    // reset the input value whenever the regulator's set point specification
+    // is updated
+    create_effect(reset_value);
+    
     view! {
         input(
             r#type="text",
-            bind:value=constraint.lorentz_prod_text,
+            class=move || {
-            on:change=move |event: Event| {
+                if valid.get() {
-                let target: HtmlInputElement = event.target().unwrap().unchecked_into();
+                    regulator.set_point.with(|set_pt| {
-                match target.value().parse::<f64>() {
+                        if set_pt.is_present() {
-                    Ok(lorentz_prod) => batch(|| {
+                            "regulator-input constraint"
-                        constraint.lorentz_prod.set(lorentz_prod);
+                        } else {
-                        constraint.lorentz_prod_valid.set(true);
+                            "regulator-input"
-                    }),
+                        }
-                    Err(_) => constraint.lorentz_prod_valid.set(false)
+                    })
-                };
+                } else {
+                    "regulator-input invalid"
+                }
+            },
+            placeholder=regulator.measurement.with(|result| result.to_string()),
+            bind:value=value,
+            on:change=move |_| {
+                valid.set(
+                    match SpecifiedValue::try_from(value.get_clone_untracked()) {
+                        Ok(set_pt) => {
+                            regulator.set_point.set(set_pt);
+                            true
+                        }
+                        Err(_) => false
+                    }
+                )
+            },
+            on:keydown={
+                move |event: KeyboardEvent| {
+                    match event.key().as_str() {
+                        "Escape" => reset_value(),
+                        _ => ()
+                    }
+                }
             }
         )
     }
 }
 
-// a list item that shows a constraint in an outline view of an element
+// a list item that shows a regulator in an outline view of an element
 #[component(inline_props)]
-fn ConstraintOutlineItem(constraint_key: ConstraintKey, element_key: ElementKey) -> View {
+fn RegulatorOutlineItem(regulator_key: RegulatorKey, element_key: ElementKey) -> View {
     let state = use_context::<AppState>();
     let assembly = &state.assembly;
-    let constraint = assembly.constraints.with(|csts| csts[constraint_key].clone());
+    let regulator = assembly.regulators.with(|regs| regs[regulator_key]);
-    let other_subject = if constraint.subjects.0 == element_key {
+    let other_subject = if regulator.subjects.0 == element_key {
-        constraint.subjects.1
+        regulator.subjects.1
     } else {
-        constraint.subjects.0
+        regulator.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()) {
+        li(class="regulator") {
-            input(r#type="checkbox", bind:checked=constraint.active)
+            div(class="regulator-label") { (other_subject_label) }
-            div(class="constraint-label") { (other_subject_label) }
+            div(class="regulator-type") { "Inversive distance" }
-            LorentzProductInput(constraint=constraint)
+            RegulatorInput(regulator=regulator)
             div(class="status")
         }
     }
@@ -74,9 +115,9 @@ fn ElementOutlineItem(key: ElementKey, element: assembly::Element) -> View {
             ).collect::<Vec<_>>()
         )
     };
-    let constrained = element.constraints.map(|csts| csts.len() > 0);
+    let regulated = element.regulators.map(|regs| regs.len() > 0);
-    let constraint_list = element.constraints.map(
+    let regulator_list = element.regulators.map(
-        |csts| csts.clone().into_iter().collect()
+        |regs| regs.clone().into_iter().collect()
     );
     let details_node = create_node_ref();
     view! {
@@ -91,7 +132,7 @@ fn ElementOutlineItem(key: ElementKey, element: assembly::Element) -> View {
                                     state.select(key, event.shift_key());
                                     event.prevent_default();
                                 },
-                                "ArrowRight" if constrained.get() => {
+                                "ArrowRight" if regulated.get() => {
                                     let _ = details_node
                                         .get()
                                         .unchecked_into::<web_sys::Element>()
@@ -138,16 +179,16 @@ fn ElementOutlineItem(key: ElementKey, element: assembly::Element) -> View {
                         div(class="status")
                     }
                 }
-                ul(class="constraints") {
+                ul(class="regulators") {
                     Keyed(
-                        list=constraint_list,
+                        list=regulator_list,
-                        view=move |cst_key| view! {
+                        view=move |reg_key| view! {
-                            ConstraintOutlineItem(
+                            RegulatorOutlineItem(
-                                constraint_key=cst_key,
+                                regulator_key=reg_key,
                                 element_key=key
                             )
                         },
-                        key=|cst_key| cst_key.clone()
+                        key=|reg_key| reg_key.clone()
                     )
                 }
             }
@@ -155,9 +196,9 @@ fn ElementOutlineItem(key: ElementKey, element: assembly::Element) -> View {
     }
 }
 
-// a component that lists the elements of the current assembly, showing the
+// a component that lists the elements of the current assembly, showing each
-// constraints on each element as a collapsible sub-list. its implementation
+// element's regulators in a collapsible sub-list. its implementation is based
-// is based on Kate Morley's HTML + CSS tree views:
+// on Kate Morley's HTML + CSS tree views:
 //
 //   https://iamkate.com/code/tree-views/
 //

app-proto/src/specified.rs

@@ -0,0 +1,44 @@
+use std::num::ParseFloatError;
+
+// a real number described by a specification string. since the structure is
+// read-only, we can guarantee that `spec` always specifies `value` in the
+// following format
+//   ┌──────────────────────────────────────────────────────┬───────────┐
+//   │ `spec`                                               │ `value`   │
+//   ┝━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┿━━━━━━━━━━━┥
+//   │ a string that parses to the floating-point value `x` │ `Some(x)` │
+//   ├──────────────────────────────────────────────────────┼───────────┤
+//   │ the empty string                                     │ `None`    │
+//   └──────────────────────────────────────────────────────┴───────────┘
+#[readonly::make]
+pub struct SpecifiedValue {
+    pub spec: String,
+    pub value: Option<f64>
+}
+
+impl SpecifiedValue {
+    pub fn from_empty_spec() -> SpecifiedValue {
+        SpecifiedValue { spec: String::new(), value: None }
+    }
+    
+    pub fn is_present(&self) -> bool {
+        matches!(self.value, Some(_))
+    }
+}
+
+// a `SpecifiedValue` can be constructed from a specification string, formatted
+// as described in the comment on the structure definition. the result is `Ok`
+// if the specification is properly formatted, and `Error` if not
+impl TryFrom<String> for SpecifiedValue {
+    type Error = ParseFloatError;
+    
+    fn try_from(spec: String) -> Result<Self, Self::Error> {
+        if spec.is_empty() {
+            Ok(SpecifiedValue::from_empty_spec())
+        } else {
+            spec.parse::<f64>().map(
+                |value| SpecifiedValue { spec: spec, value: Some(value) }
+            )
+        }
+    }
+}