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SummationByParts
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use raw pointer in simd code

This commit is contained in:
Magnus Ulimoen 2020-05-01 18:21:14 +02:00
parent 29db6b73df
commit cbf6042055
1 changed files with 82 additions and 52 deletions
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46
sbp/src/operators.rs
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@ -290,8 +290,11 @@ fn diff_op_col_simd(
type SimdT = packed_simd::f32x16;
let ny = prev.shape()[0];
// How many elements that can be simdified
let simdified = SimdT::lanes() * (ny / SimdT::lanes());
// First block
{
for (bl, mut fut) in block.iter().zip(fut.axis_iter_mut(ndarray::Axis(1))) {
fut.fill(0.0);
debug_assert_eq!(fut.len(), prev.shape()[0]);
@ -300,30 +303,49 @@ fn diff_op_col_simd(
fut.scaled_add(idx * bl, &prev);
}
}
}
// Diagonal elements
{
let half_diag_width = (diag.len() - 1) / 2;
assert!(half_diag_width <= block.len());
let fut_base_ptr = fut.as_mut_ptr();
let fut_stride = fut.strides()[1];
let fut_ptr = |j, i| {
debug_assert!(j < ny && i < nx);
unsafe { fut_base_ptr.offset(fut_stride * i as isize + j as isize) }
};
let prev_base_ptr = prev.as_ptr();
let prev_stride = prev.strides()[1];
let prev_ptr = |j, i| {
debug_assert!(j < ny && i < nx);
unsafe { prev_base_ptr.offset(prev_stride * i as isize + j as isize) }
};
assert_eq!(fut_stride, prev_stride);
for ifut in block.len()..nx - block.len() {
let simdified = SimdT::lanes() * (ny / SimdT::lanes());
for j in (0..simdified).step_by(SimdT::lanes()) {
let index_to_simd = |(j, i)| unsafe {
// gets simd along stride 1, j never goes past end of slice
// j never moves past end of slice due to step_by and
// rounding down
SimdT::from_slice_unaligned(std::slice::from_raw_parts(
prev.uget((j, i)),
prev_ptr(j, i),
SimdT::lanes(),
))
};
let mut f = SimdT::splat(0.0);
for (id, &d) in diag.iter().enumerate() {
let offset = ifut - half_diag_width + id;
f = f + d * index_to_simd((j, offset));
f = index_to_simd((j, offset)).mul_adde(SimdT::splat(d), f);
}
f = f * idx;
unsafe {
// puts simd along stride 1, j never goes past end of slice
f.write_to_slice_unaligned(std::slice::from_raw_parts_mut(
fut.uget_mut((j, ifut)),
fut_ptr(j, ifut),
SimdT::lanes(),
));
}
@ -332,12 +354,19 @@ fn diff_op_col_simd(
let mut f = 0.0;
for (id, &d) in diag.iter().enumerate() {
let offset = ifut - half_diag_width + id;
f += d * prev[(j, offset)];
}
fut[(j, ifut)] = idx * f;
unsafe {
f += d * *prev_ptr(j, offset);
}
}
unsafe {
*fut_ptr(j, ifut) = idx * f;
}
}
}
}
// End block
{
for (bl, mut fut) in block.iter().zip(fut.axis_iter_mut(ndarray::Axis(1)).rev()) {
fut.fill(0.0);
for (&bl, prev) in bl.iter().zip(prev.axis_iter(ndarray::Axis(1)).rev()) {
@ -349,6 +378,7 @@ fn diff_op_col_simd(
}
}
}
}
}
#[inline(always)]