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-rw-r--r--library/portable-simd/crates/core_simd/examples/matrix_inversion.rs316
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diff --git a/library/portable-simd/crates/core_simd/examples/matrix_inversion.rs b/library/portable-simd/crates/core_simd/examples/matrix_inversion.rs
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+++ b/library/portable-simd/crates/core_simd/examples/matrix_inversion.rs
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+//! 4x4 matrix inverse
+// Code ported from the `packed_simd` crate
+// Run this code with `cargo test --example matrix_inversion`
+#![feature(array_chunks, portable_simd)]
+use core_simd::simd::*;
+use Which::*;
+
+// Gotta define our own 4x4 matrix since Rust doesn't ship multidim arrays yet :^)
+#[derive(Copy, Clone, Debug, PartialEq, PartialOrd)]
+pub struct Matrix4x4([[f32; 4]; 4]);
+
+#[allow(clippy::too_many_lines)]
+pub fn scalar_inv4x4(m: Matrix4x4) -> Option<Matrix4x4> {
+ let m = m.0;
+
+ #[rustfmt::skip]
+ let mut inv = [
+ // row 0:
+ [
+ // 0,0:
+ m[1][1] * m[2][2] * m[3][3] -
+ m[1][1] * m[2][3] * m[3][2] -
+ m[2][1] * m[1][2] * m[3][3] +
+ m[2][1] * m[1][3] * m[3][2] +
+ m[3][1] * m[1][2] * m[2][3] -
+ m[3][1] * m[1][3] * m[2][2],
+ // 0,1:
+ -m[0][1] * m[2][2] * m[3][3] +
+ m[0][1] * m[2][3] * m[3][2] +
+ m[2][1] * m[0][2] * m[3][3] -
+ m[2][1] * m[0][3] * m[3][2] -
+ m[3][1] * m[0][2] * m[2][3] +
+ m[3][1] * m[0][3] * m[2][2],
+ // 0,2:
+ m[0][1] * m[1][2] * m[3][3] -
+ m[0][1] * m[1][3] * m[3][2] -
+ m[1][1] * m[0][2] * m[3][3] +
+ m[1][1] * m[0][3] * m[3][2] +
+ m[3][1] * m[0][2] * m[1][3] -
+ m[3][1] * m[0][3] * m[1][2],
+ // 0,3:
+ -m[0][1] * m[1][2] * m[2][3] +
+ m[0][1] * m[1][3] * m[2][2] +
+ m[1][1] * m[0][2] * m[2][3] -
+ m[1][1] * m[0][3] * m[2][2] -
+ m[2][1] * m[0][2] * m[1][3] +
+ m[2][1] * m[0][3] * m[1][2],
+ ],
+ // row 1
+ [
+ // 1,0:
+ -m[1][0] * m[2][2] * m[3][3] +
+ m[1][0] * m[2][3] * m[3][2] +
+ m[2][0] * m[1][2] * m[3][3] -
+ m[2][0] * m[1][3] * m[3][2] -
+ m[3][0] * m[1][2] * m[2][3] +
+ m[3][0] * m[1][3] * m[2][2],
+ // 1,1:
+ m[0][0] * m[2][2] * m[3][3] -
+ m[0][0] * m[2][3] * m[3][2] -
+ m[2][0] * m[0][2] * m[3][3] +
+ m[2][0] * m[0][3] * m[3][2] +
+ m[3][0] * m[0][2] * m[2][3] -
+ m[3][0] * m[0][3] * m[2][2],
+ // 1,2:
+ -m[0][0] * m[1][2] * m[3][3] +
+ m[0][0] * m[1][3] * m[3][2] +
+ m[1][0] * m[0][2] * m[3][3] -
+ m[1][0] * m[0][3] * m[3][2] -
+ m[3][0] * m[0][2] * m[1][3] +
+ m[3][0] * m[0][3] * m[1][2],
+ // 1,3:
+ m[0][0] * m[1][2] * m[2][3] -
+ m[0][0] * m[1][3] * m[2][2] -
+ m[1][0] * m[0][2] * m[2][3] +
+ m[1][0] * m[0][3] * m[2][2] +
+ m[2][0] * m[0][2] * m[1][3] -
+ m[2][0] * m[0][3] * m[1][2],
+ ],
+ // row 2
+ [
+ // 2,0:
+ m[1][0] * m[2][1] * m[3][3] -
+ m[1][0] * m[2][3] * m[3][1] -
+ m[2][0] * m[1][1] * m[3][3] +
+ m[2][0] * m[1][3] * m[3][1] +
+ m[3][0] * m[1][1] * m[2][3] -
+ m[3][0] * m[1][3] * m[2][1],
+ // 2,1:
+ -m[0][0] * m[2][1] * m[3][3] +
+ m[0][0] * m[2][3] * m[3][1] +
+ m[2][0] * m[0][1] * m[3][3] -
+ m[2][0] * m[0][3] * m[3][1] -
+ m[3][0] * m[0][1] * m[2][3] +
+ m[3][0] * m[0][3] * m[2][1],
+ // 2,2:
+ m[0][0] * m[1][1] * m[3][3] -
+ m[0][0] * m[1][3] * m[3][1] -
+ m[1][0] * m[0][1] * m[3][3] +
+ m[1][0] * m[0][3] * m[3][1] +
+ m[3][0] * m[0][1] * m[1][3] -
+ m[3][0] * m[0][3] * m[1][1],
+ // 2,3:
+ -m[0][0] * m[1][1] * m[2][3] +
+ m[0][0] * m[1][3] * m[2][1] +
+ m[1][0] * m[0][1] * m[2][3] -
+ m[1][0] * m[0][3] * m[2][1] -
+ m[2][0] * m[0][1] * m[1][3] +
+ m[2][0] * m[0][3] * m[1][1],
+ ],
+ // row 3
+ [
+ // 3,0:
+ -m[1][0] * m[2][1] * m[3][2] +
+ m[1][0] * m[2][2] * m[3][1] +
+ m[2][0] * m[1][1] * m[3][2] -
+ m[2][0] * m[1][2] * m[3][1] -
+ m[3][0] * m[1][1] * m[2][2] +
+ m[3][0] * m[1][2] * m[2][1],
+ // 3,1:
+ m[0][0] * m[2][1] * m[3][2] -
+ m[0][0] * m[2][2] * m[3][1] -
+ m[2][0] * m[0][1] * m[3][2] +
+ m[2][0] * m[0][2] * m[3][1] +
+ m[3][0] * m[0][1] * m[2][2] -
+ m[3][0] * m[0][2] * m[2][1],
+ // 3,2:
+ -m[0][0] * m[1][1] * m[3][2] +
+ m[0][0] * m[1][2] * m[3][1] +
+ m[1][0] * m[0][1] * m[3][2] -
+ m[1][0] * m[0][2] * m[3][1] -
+ m[3][0] * m[0][1] * m[1][2] +
+ m[3][0] * m[0][2] * m[1][1],
+ // 3,3:
+ m[0][0] * m[1][1] * m[2][2] -
+ m[0][0] * m[1][2] * m[2][1] -
+ m[1][0] * m[0][1] * m[2][2] +
+ m[1][0] * m[0][2] * m[2][1] +
+ m[2][0] * m[0][1] * m[1][2] -
+ m[2][0] * m[0][2] * m[1][1],
+ ],
+ ];
+
+ let det = m[0][0] * inv[0][0] + m[0][1] * inv[1][0] + m[0][2] * inv[2][0] + m[0][3] * inv[3][0];
+ if det == 0. {
+ return None;
+ }
+
+ let det_inv = 1. / det;
+
+ for row in &mut inv {
+ for elem in row.iter_mut() {
+ *elem *= det_inv;
+ }
+ }
+
+ Some(Matrix4x4(inv))
+}
+
+pub fn simd_inv4x4(m: Matrix4x4) -> Option<Matrix4x4> {
+ let m = m.0;
+ let m_0 = f32x4::from_array(m[0]);
+ let m_1 = f32x4::from_array(m[1]);
+ let m_2 = f32x4::from_array(m[2]);
+ let m_3 = f32x4::from_array(m[3]);
+
+ const SHUFFLE01: [Which; 4] = [First(0), First(1), Second(0), Second(1)];
+ const SHUFFLE02: [Which; 4] = [First(0), First(2), Second(0), Second(2)];
+ const SHUFFLE13: [Which; 4] = [First(1), First(3), Second(1), Second(3)];
+ const SHUFFLE23: [Which; 4] = [First(2), First(3), Second(2), Second(3)];
+
+ let tmp = simd_swizzle!(m_0, m_1, SHUFFLE01);
+ let row1 = simd_swizzle!(m_2, m_3, SHUFFLE01);
+
+ let row0 = simd_swizzle!(tmp, row1, SHUFFLE02);
+ let row1 = simd_swizzle!(row1, tmp, SHUFFLE13);
+
+ let tmp = simd_swizzle!(m_0, m_1, SHUFFLE23);
+ let row3 = simd_swizzle!(m_2, m_3, SHUFFLE23);
+ let row2 = simd_swizzle!(tmp, row3, SHUFFLE02);
+ let row3 = simd_swizzle!(row3, tmp, SHUFFLE13);
+
+ let tmp = (row2 * row3).reverse().rotate_lanes_right::<2>();
+ let minor0 = row1 * tmp;
+ let minor1 = row0 * tmp;
+ let tmp = tmp.rotate_lanes_right::<2>();
+ let minor0 = (row1 * tmp) - minor0;
+ let minor1 = (row0 * tmp) - minor1;
+ let minor1 = minor1.rotate_lanes_right::<2>();
+
+ let tmp = (row1 * row2).reverse().rotate_lanes_right::<2>();
+ let minor0 = (row3 * tmp) + minor0;
+ let minor3 = row0 * tmp;
+ let tmp = tmp.rotate_lanes_right::<2>();
+
+ let minor0 = minor0 - row3 * tmp;
+ let minor3 = row0 * tmp - minor3;
+ let minor3 = minor3.rotate_lanes_right::<2>();
+
+ let tmp = (row3 * row1.rotate_lanes_right::<2>())
+ .reverse()
+ .rotate_lanes_right::<2>();
+ let row2 = row2.rotate_lanes_right::<2>();
+ let minor0 = row2 * tmp + minor0;
+ let minor2 = row0 * tmp;
+ let tmp = tmp.rotate_lanes_right::<2>();
+ let minor0 = minor0 - row2 * tmp;
+ let minor2 = row0 * tmp - minor2;
+ let minor2 = minor2.rotate_lanes_right::<2>();
+
+ let tmp = (row0 * row1).reverse().rotate_lanes_right::<2>();
+ let minor2 = minor2 + row3 * tmp;
+ let minor3 = row2 * tmp - minor3;
+ let tmp = tmp.rotate_lanes_right::<2>();
+ let minor2 = row3 * tmp - minor2;
+ let minor3 = minor3 - row2 * tmp;
+
+ let tmp = (row0 * row3).reverse().rotate_lanes_right::<2>();
+ let minor1 = minor1 - row2 * tmp;
+ let minor2 = row1 * tmp + minor2;
+ let tmp = tmp.rotate_lanes_right::<2>();
+ let minor1 = row2 * tmp + minor1;
+ let minor2 = minor2 - row1 * tmp;
+
+ let tmp = (row0 * row2).reverse().rotate_lanes_right::<2>();
+ let minor1 = row3 * tmp + minor1;
+ let minor3 = minor3 - row1 * tmp;
+ let tmp = tmp.rotate_lanes_right::<2>();
+ let minor1 = minor1 - row3 * tmp;
+ let minor3 = row1 * tmp + minor3;
+
+ let det = row0 * minor0;
+ let det = det.rotate_lanes_right::<2>() + det;
+ let det = det.reverse().rotate_lanes_right::<2>() + det;
+
+ if det.reduce_sum() == 0. {
+ return None;
+ }
+ // calculate the reciprocal
+ let tmp = f32x4::splat(1.0) / det;
+ let det = tmp + tmp - det * tmp * tmp;
+
+ let res0 = minor0 * det;
+ let res1 = minor1 * det;
+ let res2 = minor2 * det;
+ let res3 = minor3 * det;
+
+ let mut m = m;
+
+ m[0] = res0.to_array();
+ m[1] = res1.to_array();
+ m[2] = res2.to_array();
+ m[3] = res3.to_array();
+
+ Some(Matrix4x4(m))
+}
+
+#[cfg(test)]
+#[rustfmt::skip]
+mod tests {
+ use super::*;
+
+ #[test]
+ fn test() {
+ let tests: &[(Matrix4x4, Option<Matrix4x4>)] = &[
+ // Identity:
+ (Matrix4x4([
+ [1., 0., 0., 0.],
+ [0., 1., 0., 0.],
+ [0., 0., 1., 0.],
+ [0., 0., 0., 1.],
+ ]),
+ Some(Matrix4x4([
+ [1., 0., 0., 0.],
+ [0., 1., 0., 0.],
+ [0., 0., 1., 0.],
+ [0., 0., 0., 1.],
+ ]))
+ ),
+ // None:
+ (Matrix4x4([
+ [1., 2., 3., 4.],
+ [12., 11., 10., 9.],
+ [5., 6., 7., 8.],
+ [16., 15., 14., 13.],
+ ]),
+ None
+ ),
+ // Other:
+ (Matrix4x4([
+ [1., 1., 1., 0.],
+ [0., 3., 1., 2.],
+ [2., 3., 1., 0.],
+ [1., 0., 2., 1.],
+ ]),
+ Some(Matrix4x4([
+ [-3., -0.5, 1.5, 1.0],
+ [ 1., 0.25, -0.25, -0.5],
+ [ 3., 0.25, -1.25, -0.5],
+ [-3., 0.0, 1.0, 1.0],
+ ]))
+ ),
+
+
+ ];
+
+ for &(input, output) in tests {
+ assert_eq!(scalar_inv4x4(input), output);
+ assert_eq!(simd_inv4x4(input), output);
+ }
+ }
+}
+
+fn main() {
+ // Empty main to make cargo happy
+}
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