forked from 1b-agent/fieldcraft-upstream
Christian Svensson
b123f31d47
A new L7 crate: the CPU scheme's collision (TRT with Guo forcing), the per-link streaming rules (bounce-back with Ladd's term, slip reflection, open placeholders), the Zou–He boundaries and the momentum exchange per force group as wgpu compute shaders, stepping the flow fieldcraft_lbm's Flow prepared, through its Backend trait: populations stay on the device, a chunk of steps is one submission, and only frames, forces and the stability check come back. Populations are stored as deviations from their weights, which keeps single precision honest: the verification cases (Poiseuille with Λ = 3/16, Couette with wall forces, Taylor–Green, a sphere's drag, a Zou–He channel) agree with the CPU to 2–5e-6 in velocity, 1e-6 in density and 5e-5 in force, with those tolerances stated in the tests. The rules are applied one thread per link rather than in a per-cell loop, which lavapipe's JIT miscompiles (and which diverges on real GPUs anyway). Native only for now; the browser registers nothing. Part of #529.
57 lines
2.1 KiB
Rust
57 lines
2.1 KiB
Rust
//! Throughput of the GPU backend (ignored; run with
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//! `cargo test --release -p fieldcraft-lbm-gpu --test throughput -- --ignored --nocapture`),
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//! on the cases of `fieldcraft-lbm`'s throughput test.
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#[path = "../../lbm/tests/common/mod.rs"]
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mod common;
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use common::*;
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use fieldcraft_gpu::select::Policy;
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use fieldcraft_lbm::backend::Backend;
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use fieldcraft_lbm_gpu::GpuFlow;
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use fieldcraft_model::{BoxFace, FaceCondition};
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#[test]
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#[ignore]
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fn cell_updates_per_second() {
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for (name, l, sphere_radius) in [("periodic box", 64usize, 0.0), ("periodic box", 128, 0.0), ("box with a sphere", 128, 32.0)] {
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let side = l as f64;
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let mut d = domain([0.0; 3], [side; 3], 1.0);
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for f in BoxFace::ALL {
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*d.faces.get_mut(f) = FaceCondition::Periodic {};
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}
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d.acceleration = [1e-6, 0.0, 0.0];
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let mut obstacles = Vec::new();
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if sphere_radius > 0.0 {
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d.obstacles = vec!["Ball".into()];
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obstacles.push(obstacle("Ball", sphere([side / 2.0; 3], sphere_radius, 4), &["skin"]));
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}
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let steps = 200;
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let m = model(
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1.0,
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1.0 / 6.0,
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d,
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fieldcraft_model::Procedure::Fluid {
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domain: "Flow".into(),
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end_time: None,
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steps: Some(steps),
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time_step: Some(1.0),
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frames: 1,
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magic: None,
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},
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);
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let (_, flow) = prepare(&m, &obstacles);
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let Ok(mut gpu) = GpuFlow::new(&flow, Policy::from_env().expect("FIELDCRAFT_GPU names a policy")) else {
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println!("skipping: no GPU");
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return;
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};
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// One warm-up chunk, then the timed run: the chunk's steps are one submission.
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gpu.advance(1).unwrap();
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let start = std::time::Instant::now();
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gpu.advance(steps).unwrap();
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let _ = gpu.mass().unwrap();
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let s = start.elapsed().as_secs_f64();
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println!("{name}, {l}³ on {}: {:.1} M cell updates/s", gpu.adapter_name(), (gpu.fluid_cells() as f64 * steps as f64) / s / 1e6);
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}
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}
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