forked from M-Labs/nalgebra
259 lines
8.8 KiB
Rust
259 lines
8.8 KiB
Rust
use alga::general::Real;
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use core::{DefaultAllocator, SquareMatrix, MatrixN};
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use core::dimension::Dim;
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use core::storage::{Storage, StorageMut};
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use core::allocator::Allocator;
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use linalg::lu;
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impl<N: Real, D: Dim, S: Storage<N, D, D>> SquareMatrix<N, D, S> {
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/// Attempts to invert this matrix.
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#[inline]
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pub fn try_inverse(self) -> Option<MatrixN<N, D>>
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where DefaultAllocator: Allocator<N, D, D> {
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let mut me = self.into_owned();
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if me.try_inverse_mut() {
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Some(me)
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}
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else {
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None
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}
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}
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}
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impl<N: Real, D: Dim, S: StorageMut<N, D, D>> SquareMatrix<N, D, S> {
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/// Attempts to invert this matrix in-place. Returns `false` and leaves `self` untouched if
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/// inversion fails.
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#[inline]
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pub fn try_inverse_mut(&mut self) -> bool
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where DefaultAllocator: Allocator<N, D, D> {
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assert!(self.is_square(), "Unable to invert a non-square matrix.");
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let dim = self.shape().0;
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unsafe {
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match dim {
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0 => true,
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1 => {
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let determinant = self.get_unchecked(0, 0).clone();
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if determinant == N::zero() {
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false
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}
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else {
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*self.get_unchecked_mut(0, 0) = N::one() / determinant;
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true
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}
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},
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2 => {
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let m11 = *self.get_unchecked(0, 0); let m12 = *self.get_unchecked(0, 1);
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let m21 = *self.get_unchecked(1, 0); let m22 = *self.get_unchecked(1, 1);
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let determinant = m11 * m22 - m21 * m12;
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if determinant == N::zero() {
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false
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}
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else {
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*self.get_unchecked_mut(0, 0) = m22 / determinant;
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*self.get_unchecked_mut(0, 1) = -m12 / determinant;
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*self.get_unchecked_mut(1, 0) = -m21 / determinant;
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*self.get_unchecked_mut(1, 1) = m11 / determinant;
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true
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}
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},
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3 => {
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let m11 = *self.get_unchecked(0, 0);
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let m12 = *self.get_unchecked(0, 1);
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let m13 = *self.get_unchecked(0, 2);
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let m21 = *self.get_unchecked(1, 0);
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let m22 = *self.get_unchecked(1, 1);
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let m23 = *self.get_unchecked(1, 2);
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let m31 = *self.get_unchecked(2, 0);
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let m32 = *self.get_unchecked(2, 1);
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let m33 = *self.get_unchecked(2, 2);
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let minor_m12_m23 = m22 * m33 - m32 * m23;
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let minor_m11_m23 = m21 * m33 - m31 * m23;
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let minor_m11_m22 = m21 * m32 - m31 * m22;
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let determinant = m11 * minor_m12_m23 -
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m12 * minor_m11_m23 +
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m13 * minor_m11_m22;
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if determinant == N::zero() {
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false
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}
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else {
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*self.get_unchecked_mut(0, 0) = minor_m12_m23 / determinant;
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*self.get_unchecked_mut(0, 1) = (m13 * m32 - m33 * m12) / determinant;
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*self.get_unchecked_mut(0, 2) = (m12 * m23 - m22 * m13) / determinant;
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*self.get_unchecked_mut(1, 0) = -minor_m11_m23 / determinant;
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*self.get_unchecked_mut(1, 1) = (m11 * m33 - m31 * m13) / determinant;
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*self.get_unchecked_mut(1, 2) = (m13 * m21 - m23 * m11) / determinant;
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*self.get_unchecked_mut(2, 0) = minor_m11_m22 / determinant;
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*self.get_unchecked_mut(2, 1) = (m12 * m31 - m32 * m11) / determinant;
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*self.get_unchecked_mut(2, 2) = (m11 * m22 - m21 * m12) / determinant;
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true
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}
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},
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4=> {
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let oself = self.clone_owned();
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do_inverse4(&oself, self)
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}
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_ => {
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let oself = self.clone_owned();
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lu::try_invert_to(oself, self)
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}
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}
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}
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}
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}
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// NOTE: this is an extremely efficient, loop-unrolled matrix inverse from MESA (MIT licenced).
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fn do_inverse4<N: Real, D: Dim, S: StorageMut<N, D, D>>(m: &MatrixN<N, D>, out: &mut SquareMatrix<N, D, S>) -> bool
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where DefaultAllocator: Allocator<N, D, D> {
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let m = m.data.as_slice();
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out[(0, 0)] = m[5] * m[10] * m[15] -
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m[5] * m[11] * m[14] -
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m[9] * m[6] * m[15] +
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m[9] * m[7] * m[14] +
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m[13] * m[6] * m[11] -
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m[13] * m[7] * m[10];
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out[(1, 0)] = -m[1] * m[10] * m[15] +
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m[1] * m[11] * m[14] +
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m[9] * m[2] * m[15] -
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m[9] * m[3] * m[14] -
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m[13] * m[2] * m[11] +
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m[13] * m[3] * m[10];
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out[(2, 0)] = m[1] * m[6] * m[15] -
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m[1] * m[7] * m[14] -
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m[5] * m[2] * m[15] +
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m[5] * m[3] * m[14] +
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m[13] * m[2] * m[7] -
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m[13] * m[3] * m[6];
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out[(3, 0)] = -m[1] * m[6] * m[11] +
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m[1] * m[7] * m[10] +
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m[5] * m[2] * m[11] -
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m[5] * m[3] * m[10] -
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m[9] * m[2] * m[7] +
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m[9] * m[3] * m[6];
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out[(0, 1)] = -m[4] * m[10] * m[15] +
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m[4] * m[11] * m[14] +
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m[8] * m[6] * m[15] -
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m[8] * m[7] * m[14] -
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m[12] * m[6] * m[11] +
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m[12] * m[7] * m[10];
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out[(1, 1)] = m[0] * m[10] * m[15] -
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m[0] * m[11] * m[14] -
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m[8] * m[2] * m[15] +
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m[8] * m[3] * m[14] +
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m[12] * m[2] * m[11] -
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m[12] * m[3] * m[10];
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out[(2, 1)] = -m[0] * m[6] * m[15] +
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m[0] * m[7] * m[14] +
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m[4] * m[2] * m[15] -
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m[4] * m[3] * m[14] -
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m[12] * m[2] * m[7] +
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m[12] * m[3] * m[6];
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out[(3, 1)] = m[0] * m[6] * m[11] -
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m[0] * m[7] * m[10] -
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m[4] * m[2] * m[11] +
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m[4] * m[3] * m[10] +
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m[8] * m[2] * m[7] -
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m[8] * m[3] * m[6];
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out[(0, 2)] = m[4] * m[9] * m[15] -
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m[4] * m[11] * m[13] -
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m[8] * m[5] * m[15] +
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m[8] * m[7] * m[13] +
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m[12] * m[5] * m[11] -
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m[12] * m[7] * m[9];
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out[(1, 2)] = -m[0] * m[9] * m[15] +
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m[0] * m[11] * m[13] +
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m[8] * m[1] * m[15] -
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m[8] * m[3] * m[13] -
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m[12] * m[1] * m[11] +
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m[12] * m[3] * m[9];
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out[(2, 2)] = m[0] * m[5] * m[15] -
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m[0] * m[7] * m[13] -
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m[4] * m[1] * m[15] +
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m[4] * m[3] * m[13] +
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m[12] * m[1] * m[7] -
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m[12] * m[3] * m[5];
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out[(0, 3)] = -m[4] * m[9] * m[14] +
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m[4] * m[10] * m[13] +
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m[8] * m[5] * m[14] -
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m[8] * m[6] * m[13] -
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m[12] * m[5] * m[10] +
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m[12] * m[6] * m[9];
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out[(3, 2)] = -m[0] * m[5] * m[11] +
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m[0] * m[7] * m[9] +
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m[4] * m[1] * m[11] -
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m[4] * m[3] * m[9] -
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m[8] * m[1] * m[7] +
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m[8] * m[3] * m[5];
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out[(1, 3)] = m[0] * m[9] * m[14] -
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m[0] * m[10] * m[13] -
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m[8] * m[1] * m[14] +
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m[8] * m[2] * m[13] +
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m[12] * m[1] * m[10] -
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m[12] * m[2] * m[9];
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out[(2, 3)] = -m[0] * m[5] * m[14] +
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m[0] * m[6] * m[13] +
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m[4] * m[1] * m[14] -
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m[4] * m[2] * m[13] -
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m[12] * m[1] * m[6] +
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m[12] * m[2] * m[5];
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out[(3, 3)] = m[0] * m[5] * m[10] -
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m[0] * m[6] * m[9] -
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m[4] * m[1] * m[10] +
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m[4] * m[2] * m[9] +
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m[8] * m[1] * m[6] -
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m[8] * m[2] * m[5];
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let det = m[0] * out[(0, 0)] + m[1] * out[(0, 1)] + m[2] * out[(0, 2)] + m[3] * out[(0, 3)];
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if !det.is_zero() {
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let inv_det = N::one() / det;
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for j in 0 .. 4 {
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for i in 0 .. 4 {
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out[(i, j)] *= inv_det;
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}
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}
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true
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}
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else {
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false
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}
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}
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