refactor: Tidy up engine tests (#72)

### `zero_loss_test`
  - Drop the redundant type hint in the definition of `a`.

  ### `tangent_test_three_spheres`
  - Get the dimension from the expected basis, rather than putting it in by hand.

  ### `tangent_test_kaleidocycle`
  - Factor out the realization code, in the same style as `realize_irisawa_hexlet`.
  - Rename the `irisawa` submodule to `examples`.

  ### `frozen_entry_test`
  - Move up into the section for simpler tests, between `zero_loss_test` and `irisawa_hexlet_test`.

Co-authored-by: Aaron Fenyes <aaron.fenyes@fareycircles.ooo>
Reviewed-on: glen/dyna3#72
Reviewed-by: Glen Whitney <glen@nobody@nowhere.net>
Co-authored-by: Vectornaut <vectornaut@nobody@nowhere.net>
Co-committed-by: Vectornaut <vectornaut@nobody@nowhere.net>
This commit is contained in:
Vectornaut 2025-03-12 21:54:56 +00:00 committed by Glen Whitney
parent da28bc99d2
commit 2c4fd39c1f
3 changed files with 121 additions and 151 deletions

View file

@ -1,4 +1,4 @@
use dyna3::engine::{Q, irisawa::realize_irisawa_hexlet};
use dyna3::engine::{Q, examples::realize_irisawa_hexlet};
fn main() {
const SCALED_TOL: f64 = 1.0e-12;

View file

@ -1,53 +1,10 @@
use nalgebra::{DMatrix, DVector};
use std::{array, f64::consts::PI};
use dyna3::engine::{Q, point, realize_gram, PartialMatrix};
use dyna3::engine::{Q, examples::realize_kaleidocycle};
fn main() {
// set up a kaleidocycle, made of points with fixed distances between them,
// and find its tangent space
const N_POINTS: usize = 12;
let gram = {
let mut gram_to_be = PartialMatrix::new();
for block in (0..N_POINTS).step_by(2) {
let block_next = (block + 2) % N_POINTS;
for j in 0..2 {
// diagonal and hinge edges
for k in j..2 {
gram_to_be.push_sym(block + j, block + k, if j == k { 0.0 } else { -0.5 });
}
// non-hinge edges
for k in 0..2 {
gram_to_be.push_sym(block + j, block_next + k, -0.625);
}
}
}
gram_to_be
};
let guess = {
const N_HINGES: usize = 6;
let guess_elts = (0..N_HINGES).step_by(2).flat_map(
|n| {
let ang_hor = (n as f64) * PI/3.0;
let ang_vert = ((n + 1) as f64) * PI/3.0;
let x_vert = ang_vert.cos();
let y_vert = ang_vert.sin();
[
point(0.0, 0.0, 0.0),
point(ang_hor.cos(), ang_hor.sin(), 0.0),
point(x_vert, y_vert, -0.5),
point(x_vert, y_vert, 0.5)
]
}
).collect::<Vec<_>>();
DMatrix::from_columns(&guess_elts)
};
let frozen: [_; N_POINTS] = array::from_fn(|k| (3, k));
let (config, tangent, success, history) = realize_gram(
&gram, guess, &frozen,
1.0e-12, 0.5, 0.9, 1.1, 200, 110
);
const SCALED_TOL: f64 = 1.0e-12;
let (config, tangent, success, history) = realize_kaleidocycle(SCALED_TOL);
print!("Completed Gram matrix:{}", config.tr_mul(&*Q) * &config);
print!("Configuration:{}", config);
if success {
@ -58,7 +15,8 @@ fn main() {
println!("Steps: {}", history.scaled_loss.len() - 1);
println!("Loss: {}\n", history.scaled_loss.last().unwrap());
// find the kaleidocycle's twist motion
// find the kaleidocycle's twist motion by projecting onto the tangent space
const N_POINTS: usize = 12;
let up = DVector::from_column_slice(&[0.0, 0.0, 1.0, 0.0]);
let down = -&up;
let twist_motion: DMatrix<_> = (0..N_POINTS).step_by(4).flat_map(

View file

@ -413,20 +413,20 @@ pub fn realize_gram(
// --- tests ---
// 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/
//
#[cfg(feature = "dev")]
pub mod irisawa {
pub mod examples {
use std::{array, f64::consts::PI};
use super::*;
// 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/
//
pub fn realize_irisawa_hexlet(scaled_tol: f64) -> (DMatrix<f64>, ConfigSubspace, bool, DescentHistory) {
let gram = {
let mut gram_to_be = PartialMatrix::new();
@ -480,14 +480,64 @@ pub mod irisawa {
scaled_tol, 0.5, 0.9, 1.1, 200, 110
)
}
// set up a kaleidocycle, made of points with fixed distances between them,
// and find its tangent space
pub fn realize_kaleidocycle(scaled_tol: f64) -> (DMatrix<f64>, ConfigSubspace, bool, DescentHistory) {
const N_POINTS: usize = 12;
let gram = {
let mut gram_to_be = PartialMatrix::new();
for block in (0..N_POINTS).step_by(2) {
let block_next = (block + 2) % N_POINTS;
for j in 0..2 {
// diagonal and hinge edges
for k in j..2 {
gram_to_be.push_sym(block + j, block + k, if j == k { 0.0 } else { -0.5 });
}
// non-hinge edges
for k in 0..2 {
gram_to_be.push_sym(block + j, block_next + k, -0.625);
}
}
}
gram_to_be
};
let guess = {
const N_HINGES: usize = 6;
let guess_elts = (0..N_HINGES).step_by(2).flat_map(
|n| {
let ang_hor = (n as f64) * PI/3.0;
let ang_vert = ((n + 1) as f64) * PI/3.0;
let x_vert = ang_vert.cos();
let y_vert = ang_vert.sin();
[
point(0.0, 0.0, 0.0),
point(ang_hor.cos(), ang_hor.sin(), 0.0),
point(x_vert, y_vert, -0.5),
point(x_vert, y_vert, 0.5)
]
}
).collect::<Vec<_>>();
DMatrix::from_columns(&guess_elts)
};
let frozen: [_; N_POINTS] = array::from_fn(|k| (3, k));
realize_gram(
&gram, guess, &frozen,
scaled_tol, 0.5, 0.9, 1.1, 200, 110
)
}
}
#[cfg(test)]
mod tests {
use nalgebra::Vector3;
use std::{array, f64::consts::{FRAC_1_SQRT_2, PI}, iter};
use std::{f64::consts::{FRAC_1_SQRT_2, PI}, iter};
use super::{*, irisawa::realize_irisawa_hexlet};
use super::{*, examples::*};
#[test]
fn sub_proj_test() {
@ -523,7 +573,7 @@ mod tests {
entries
});
let config = {
let a: f64 = 0.75_f64.sqrt();
let a = 0.75_f64.sqrt();
DMatrix::from_columns(&[
sphere(1.0, 0.0, 0.0, a),
sphere(-0.5, a, 0.0, a),
@ -534,6 +584,40 @@ mod tests {
assert!(state.loss.abs() < f64::EPSILON);
}
// 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]);
}
}
#[test]
fn irisawa_hexlet_test() {
// solve Irisawa's problem
@ -574,12 +658,8 @@ mod tests {
assert_eq!(success, true);
assert_eq!(history.scaled_loss.len(), 1);
// confirm that the tangent space has dimension five or less
assert_eq!(tangent.basis_std.len(), 5);
// confirm that the tangent space contains all the motions we expect it
// to. since we've already bounded the dimension of the tangent space,
// this confirms that the tangent space is what we expect it to be
// list some motions that should form a basis for the tangent space of
// the solution variety
const UNIFORM_DIM: usize = 4;
let element_dim = guess.nrows();
let assembly_dim = guess.ncols();
@ -605,6 +685,14 @@ mod tests {
0.0, 0.0, -1.0, 0.25, 1.0
])
];
// confirm that the dimension of the tangent space is no greater than
// expected
assert_eq!(tangent.basis_std.len(), tangent_motions_std.len());
// confirm that the tangent space contains all the motions we expect it
// to. since we've already bounded the dimension of the tangent space,
// this confirms that the tangent space is what we expect it to be
let tol_sq = ((element_dim * assembly_dim) as f64) * SCALED_TOL * SCALED_TOL;
for (motion_unif, motion_std) in tangent_motions_unif.into_iter().zip(tangent_motions_std) {
let motion_proj: DMatrix<_> = motion_unif.column_iter().enumerate().map(
@ -633,59 +721,17 @@ mod tests {
#[test]
fn tangent_test_kaleidocycle() {
// set up a kaleidocycle, made of points with fixed distances between
// them, and find its tangent space
const N_POINTS: usize = 12;
const N_HINGES: usize = 6;
// set up a kaleidocycle and find its tangent space
const SCALED_TOL: f64 = 1.0e-12;
let gram = {
let mut gram_to_be = PartialMatrix::new();
for block in (0..N_POINTS).step_by(2) {
let block_next = (block + 2) % N_POINTS;
for j in 0..2 {
// diagonal and hinge edges
for k in j..2 {
gram_to_be.push_sym(block + j, block + k, if j == k { 0.0 } else { -0.5 });
}
// non-hinge edges
for k in 0..2 {
gram_to_be.push_sym(block + j, block_next + k, -0.625);
}
}
}
gram_to_be
};
let guess = {
let guess_elts = (0..N_HINGES).step_by(2).flat_map(
|n| {
let ang_hor = (n as f64) * PI/3.0;
let ang_vert = ((n + 1) as f64) * PI/3.0;
let x_vert = ang_vert.cos();
let y_vert = ang_vert.sin();
[
point(0.0, 0.0, 0.0),
point(ang_hor.cos(), ang_hor.sin(), 0.0),
point(x_vert, y_vert, -0.5),
point(x_vert, y_vert, 0.5)
]
}
).collect::<Vec<_>>();
DMatrix::from_columns(&guess_elts)
};
let frozen: [_; N_POINTS] = array::from_fn(|k| (3, k));
let (config, tangent, success, history) = realize_gram(
&gram, guess.clone(), &frozen,
SCALED_TOL, 0.5, 0.9, 1.1, 200, 110
);
assert_eq!(config, guess);
let (config, tangent, success, history) = realize_kaleidocycle(SCALED_TOL);
assert_eq!(success, true);
assert_eq!(history.scaled_loss.len(), 1);
// list some motions that should form a basis for the tangent space of
// the solution variety
let element_dim = guess.nrows();
let assembly_dim = guess.ncols();
const N_HINGES: usize = 6;
let element_dim = config.nrows();
let assembly_dim = config.ncols();
let tangent_motions_unif = vec![
// the translations along the coordinate axes
translation_motion_unif(&Vector3::new(1.0, 0.0, 0.0), assembly_dim),
@ -693,9 +739,9 @@ mod tests {
translation_motion_unif(&Vector3::new(0.0, 0.0, 1.0), assembly_dim),
// the rotations about the coordinate axes
rotation_motion_unif(&Vector3::new(1.0, 0.0, 0.0), guess.column_iter().collect()),
rotation_motion_unif(&Vector3::new(0.0, 1.0, 0.0), guess.column_iter().collect()),
rotation_motion_unif(&Vector3::new(0.0, 0.0, 1.0), guess.column_iter().collect()),
rotation_motion_unif(&Vector3::new(1.0, 0.0, 0.0), config.column_iter().collect()),
rotation_motion_unif(&Vector3::new(0.0, 1.0, 0.0), config.column_iter().collect()),
rotation_motion_unif(&Vector3::new(0.0, 0.0, 1.0), config.column_iter().collect()),
// the twist motion. more precisely: a motion that keeps the center
// of mass stationary and preserves the distances between the
@ -720,7 +766,7 @@ mod tests {
];
let tangent_motions_std = tangent_motions_unif.iter().map(
|motion| DMatrix::from_columns(
&guess.column_iter().zip(motion).map(
&config.column_iter().zip(motion).map(
|(v, elt_motion)| local_unif_to_std(v) * elt_motion
).collect::<Vec<_>>()
)
@ -826,38 +872,4 @@ mod tests {
let tol_sq = ((guess_orig.nrows() * guess_orig.ncols()) as f64) * SCALED_TOL_TFM * SCALED_TOL_TFM;
assert!((motion_proj_tfm - motion_tfm_proj).norm_squared() < tol_sq);
}
// 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]);
}
}
}