diff options
| -rw-r--r-- | crates/core_simd/examples/nbody.rs | 39 |
1 files changed, 18 insertions, 21 deletions
diff --git a/crates/core_simd/examples/nbody.rs b/crates/core_simd/examples/nbody.rs index 4fdc0226397..5873f311947 100644 --- a/crates/core_simd/examples/nbody.rs +++ b/crates/core_simd/examples/nbody.rs @@ -1,3 +1,6 @@ +/// Benchmarks game nbody code +/// Taken from the `packed_simd` crate +/// Run this benchmark with `cargo test --example body` use core_simd::*; use std::f64::consts::PI; @@ -126,11 +129,14 @@ pub fn advance(bodies: &mut [Body; N_BODIES], dt: f64) { let mut mag = [0.0; N]; let mut i = 0; while i < N { - let d2s = f64x2::from_array([(r[i] * r[i]).horizontal_sum(), (r[i + 1] * r[i + 1]).horizontal_sum()]); + let d2s = f64x2::from_array([ + (r[i] * r[i]).horizontal_sum(), + (r[i + 1] * r[i + 1]).horizontal_sum(), + ]); let dmags = f64x2::splat(dt) / (d2s * d2s.sqrt()); // dmags.write_to_slice_unaligned(&mut mag[i..]); mag[i] = dmags[0]; - mag[i+1] = dmags[1]; + mag[i + 1] = dmags[1]; i += 2; } @@ -166,28 +172,19 @@ pub fn run(n: usize) -> (f64, f64) { (energy_before, energy_after) } -const OUTPUT: [f64; 2] = [-0.169075164, -0.169087605]; +fn approx_eq_f32(a: f32, b: f32) -> bool { + (a - b).abs() < 0.00000001 +} + #[cfg(test)] mod tests { #[test] fn test() { - let mut out: Vec<u8> = Vec::new(); - run(&mut out, 1000, 0); - for &(size, a_e, b_e) in crate::RESULTS { - let (a, b) = super::run(size); - assert_eq!(format!("{:.9}", a), a_e); - assert_eq!(format!("{:.9}", b), b_e); - } + use super::*; + const OUTPUT: [f64; 2] = [-0.169075164, -0.169087605]; + let (energy_before, energy_after) = super::run(1000); + assert!(approx_eq_f32(energy_before as f32, OUTPUT[0] as f32)); + assert!(approx_eq_f32(energy_after as f32, OUTPUT[1] as f32)); + // } } } - - -fn main() { - //let n: usize = std::env::args() - //.nth(1) - //.expect("need one arg") - //.parse() - //.expect("argument should be a usize"); - //run(&mut std::io::stdout(), n, alg); - println!("{:?}", run(10)); -} |