swaits
8cf518200a
Adds heuropt-plot, a tiny SVG-only plotter that takes heuropt results and emits scatter plots (pareto_front_svg) and line plots (convergence_svg). No heavy 'plotters' or 'tiny-skia' dep — hand- rolled SVG so the crate adds <100 KB to a build. Workspace setup: root Cargo.toml gains [workspace] with members = ['.', 'heuropt-plot']. heuropt-plot has its own version (0.1.0) and publishes independently against heuropt 0.7+. Adds examples/visualize.rs that wires it all up: NSGA-II on Schaffer N.1, observer closure recording per-generation hypervolume, two SVGs written to disk.
90 lines
2.7 KiB
Rust
90 lines
2.7 KiB
Rust
//! Visualize an NSGA-II run on Schaffer N.1 — produces two SVGs:
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//! `pareto_front.svg` (scatter plot of the final front) and
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//! `convergence.svg` (best-so-far hypervolume per generation).
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//!
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//! Uses the `heuropt-plot` companion crate plus the v0.6 observer
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//! API (`Periodic`) to record per-generation hypervolume into a Vec
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//! during the run.
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//!
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//! Run with: `cargo run --release --example visualize`
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use std::cell::RefCell;
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use std::ops::ControlFlow;
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use heuropt::metrics::hypervolume_2d;
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use heuropt::prelude::*;
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use heuropt_plot::{convergence_svg, pareto_front_svg};
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struct Schaffer;
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impl Problem for Schaffer {
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type Decision = Vec<f64>;
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fn objectives(&self) -> ObjectiveSpace {
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ObjectiveSpace::new(vec![Objective::minimize("f1"), Objective::minimize("f2")])
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}
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fn evaluate(&self, x: &Vec<f64>) -> Evaluation {
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Evaluation::new(vec![x[0] * x[0], (x[0] - 2.0).powi(2)])
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}
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}
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fn main() {
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let problem = Schaffer;
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let bounds = vec![(-5.0_f64, 5.0_f64)];
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let space = problem.objectives();
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let ref_point = [10.0, 10.0];
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// Per-generation hypervolume trace, recorded by the observer.
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let history: RefCell<Vec<f64>> = RefCell::new(Vec::new());
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let mut recorder = |snap: &Snapshot<'_, Vec<f64>>| -> ControlFlow<()> {
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let hv = match snap.pareto_front {
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Some(front) => hypervolume_2d(front, snap.objectives, ref_point),
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None => 0.0,
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};
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history.borrow_mut().push(hv);
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ControlFlow::Continue(())
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};
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let mut opt = Nsga2::new(
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Nsga2Config {
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population_size: 50,
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generations: 100,
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seed: 42,
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},
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RealBounds::new(bounds.clone()),
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CompositeVariation {
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crossover: SimulatedBinaryCrossover::new(bounds.clone(), 15.0, 0.5),
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mutation: PolynomialMutation::new(bounds, 20.0, 1.0),
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},
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);
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let result = opt.run_with(&problem, &mut recorder);
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let front_svg = pareto_front_svg(
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&result.pareto_front,
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&space,
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700,
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450,
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"NSGA-II on Schaffer N.1 — final Pareto front",
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);
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std::fs::write("pareto_front.svg", front_svg).expect("write pareto_front.svg");
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let trace = history.borrow();
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let conv_svg = convergence_svg(
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&trace,
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700,
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450,
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"NSGA-II on Schaffer N.1 — hypervolume per generation",
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"hypervolume",
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false, // higher is better
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);
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std::fs::write("convergence.svg", conv_svg).expect("write convergence.svg");
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println!("Final front size: {}", result.pareto_front.len());
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println!(
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"Final hypervolume: {:.4}",
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trace.last().copied().unwrap_or(0.0)
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);
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println!("Wrote pareto_front.svg and convergence.svg");
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}
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