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use simd for diffy

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This commit is contained in:
Magnus Ulimoen
2019-11-09 12:58:14 +01:00
parent 6db06d108d
commit bf9037e155
3 changed files with 108 additions and 14 deletions
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119
src/operators/upwind4.rs
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@@ -144,6 +144,90 @@ impl Upwind4 {
}
}
fn diffy_simd(prev: &[f32], fut: &mut [f32], nx: usize, ny: usize) {
use packed_simd::f32x4;
assert!(ny > 8);
assert!(nx > 4);
assert!(nx % 4 == 0);
assert_eq!(prev.len(), fut.len());
assert_eq!(prev.len(), nx * ny);
let dy = 1.0 / (ny - 1) as f32;
let idy = 1.0 / dy;
for j in (0..nx).step_by(4) {
let a = [
f32x4::from_slice_unaligned(&prev[0 * nx + j..]),
f32x4::from_slice_unaligned(&prev[1 * nx + j..]),
f32x4::from_slice_unaligned(&prev[2 * nx + j..]),
f32x4::from_slice_unaligned(&prev[3 * nx + j..]),
f32x4::from_slice_unaligned(&prev[4 * nx + j..]),
f32x4::from_slice_unaligned(&prev[5 * nx + j..]),
f32x4::from_slice_unaligned(&prev[6 * nx + j..]),
];
for (i, bl) in Self::BLOCK.iter().enumerate() {
let mut b = f32x4::from_slice_unaligned(&fut[i * nx + j..]);
b += idy
* (a[0] * bl[0]
+ a[1] * bl[1]
+ a[2] * bl[2]
+ a[3] * bl[3]
+ a[4] * bl[4]
+ a[5] * bl[5]
+ a[6] * bl[6]);
b.write_to_slice_unaligned(&mut fut[i * nx + j..]);
}
let mut a = a;
for i in Self::BLOCK.len()..ny - Self::BLOCK.len() {
// Push a onto circular buffer
a = [
a[1],
a[2],
a[3],
a[4],
a[5],
a[6],
f32x4::from_slice_unaligned(&prev[nx * (i + 3) + j..]),
];
let mut b = f32x4::from_slice_unaligned(&fut[nx * i + j..]);
b += idy
* (a[0] * Self::DIAG[0]
+ a[1] * Self::DIAG[1]
+ a[2] * Self::DIAG[2]
+ a[3] * Self::DIAG[3]
+ a[4] * Self::DIAG[4]
+ a[5] * Self::DIAG[5]
+ a[6] * Self::DIAG[6]);
b.write_to_slice_unaligned(&mut fut[nx * i + j..]);
}
let a = [
f32x4::from_slice_unaligned(&prev[(ny - 1) * nx + j..]),
f32x4::from_slice_unaligned(&prev[(ny - 2) * nx + j..]),
f32x4::from_slice_unaligned(&prev[(ny - 3) * nx + j..]),
f32x4::from_slice_unaligned(&prev[(ny - 4) * nx + j..]),
f32x4::from_slice_unaligned(&prev[(ny - 5) * nx + j..]),
f32x4::from_slice_unaligned(&prev[(ny - 6) * nx + j..]),
f32x4::from_slice_unaligned(&prev[(ny - 7) * nx + j..]),
];
for (i, bl) in Self::BLOCK.iter().enumerate() {
let mut b = f32x4::from_slice_unaligned(&fut[(ny - 1 - i) * nx + j..]);
b += -idy
* (a[0] * bl[0]
+ a[1] * bl[1]
+ a[2] * bl[2]
+ a[3] * bl[3]
+ a[4] * bl[4]
+ a[5] * bl[5]
+ a[6] * bl[6]);
b.write_to_slice_unaligned(&mut fut[(ny - 1 - i) * nx + j..]);
}
}
}
fn diff(prev: ArrayView1<f32>, mut fut: ArrayViewMut1<f32>) {
assert_eq!(prev.shape(), fut.shape());
let nx = prev.shape()[0];
@@ -186,6 +270,7 @@ impl Upwind4 {
#[test]
fn upwind4_test() {
use ndarray::prelude::*;
let nx = 20;
let dx = 1.0 / (nx - 1) as f32;
let mut source: ndarray::Array1<f32> = ndarray::Array1::zeros(nx);
@@ -209,12 +294,12 @@ fn upwind4_test() {
}
{
let source = source.to_owned().insert_axis(ndarray::Axis(1));
let mut res = res.to_owned().insert_axis(ndarray::Axis(1));
let target = target.to_owned().insert_axis(ndarray::Axis(1));
let source = Array2::from_shape_fn((nx, 8), |(i, _)| source[i]);
let target = Array2::from_shape_fn((nx, 8), |(i, _)| target[i]);
let mut res = Array2::zeros((nx, 8));
res.fill(0.0);
Upwind4::diffy(source.view(), res.view_mut());
approx::assert_abs_diff_eq!(&res, &target, epsilon = 1e-2);
approx::assert_abs_diff_eq!(&res.to_owned(), &target.to_owned(), epsilon = 1e-2);
}
for i in 0..nx {
@@ -235,12 +320,12 @@ fn upwind4_test() {
}
{
let source = source.to_owned().insert_axis(ndarray::Axis(1));
let mut res = res.to_owned().insert_axis(ndarray::Axis(1));
let target = target.to_owned().insert_axis(ndarray::Axis(1));
let source = Array2::from_shape_fn((nx, 8), |(i, _)| source[i]);
let target = Array2::from_shape_fn((nx, 8), |(i, _)| target[i]);
let mut res = Array2::zeros((nx, 8));
res.fill(0.0);
Upwind4::diffy(source.view(), res.view_mut());
approx::assert_abs_diff_eq!(&res, &target, epsilon = 1e-2);
approx::assert_abs_diff_eq!(&res.to_owned(), &target.to_owned(), epsilon = 1e-2);
}
for i in 0..nx {
@@ -262,12 +347,12 @@ fn upwind4_test() {
}
{
let source = source.to_owned().insert_axis(ndarray::Axis(1));
let mut res = res.to_owned().insert_axis(ndarray::Axis(1));
let target = target.to_owned().insert_axis(ndarray::Axis(1));
let source = Array2::from_shape_fn((nx, 8), |(i, _)| source[i]);
let target = Array2::from_shape_fn((nx, 8), |(i, _)| target[i]);
let mut res = Array2::zeros((nx, 8));
res.fill(0.0);
Upwind4::diffy(source.view(), res.view_mut());
approx::assert_abs_diff_eq!(&res, &target, epsilon = 1e-2);
approx::assert_abs_diff_eq!(&res.to_owned(), &target.to_owned(), epsilon = 1e-2);
}
}
@@ -278,7 +363,15 @@ impl SbpOperator for Upwind4 {
}
}
fn diffy(prev: ArrayView2<f32>, fut: ArrayViewMut2<f32>) {
fn diffy(prev: ArrayView2<f32>, mut fut: ArrayViewMut2<f32>) {
let nx = prev.shape()[1];
let ny = prev.shape()[0];
if nx >= 4 && nx % 4 == 0 {
if let (Some(p), Some(f)) = (prev.as_slice(), fut.as_slice_mut()) {
Self::diffy_simd(p, f, nx, ny);
return;
}
}
// diffy = transpose then use diffx
Self::diffx(prev.reversed_axes(), fut.reversed_axes());
}