Adjust normalization step of nudge routine #43

Merged
glen merged 3 commits from normalize-by-contracting into main 2025-02-06 22:53:42 +00:00

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@ -5,7 +5,7 @@ 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, Q};
use crate::engine::{realize_gram, local_unif_to_std, ConfigSubspace, PartialMatrix};
// the types of the keys we use to access an assembly's elements and constraints
pub type ElementKey = usize;
@ -371,8 +371,8 @@ impl Assembly {
}
}
// step each element along the mass shell geodesic that matches its
// velocity in the deformation found above
// step the assembly along the deformation. this changes the elements'
// normalizations, so we restore those afterward
/* KLUDGE */
// since our test assemblies only include spheres, we assume that every
// element is on the 1 mass shell
@ -380,9 +380,16 @@ impl Assembly {
elt.representation.update_silent(|rep| {
match elt.column_index {
Some(column_index) => {
let rep_next = &*rep + motion_proj.column(column_index);
let normalizer = rep_next.dot(&(&*Q * &rep_next));
rep.set_column(0, &(rep_next / normalizer));
// step the assembly along the deformation
*rep += motion_proj.column(column_index);
// restore normalization by contracting toward the last
// coordinate axis
let q_sp = rep.fixed_rows::<3>(0).norm_squared();
let half_q_lt = -2.0 * rep[3] * rep[4];
let half_q_lt_sq = half_q_lt * half_q_lt;
let scaling = half_q_lt + (q_sp + half_q_lt_sq).sqrt();
rep.fixed_rows_mut::<4>(0).scale_mut(1.0 / scaling);
},
None => {
console::log_1(&JsValue::from(