| /* Copyright 2015 The Chromium OS Authors. All rights reserved. |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include "common.h" |
| #include "mat44.h" |
| #include "math.h" |
| #include "util.h" |
| |
| #define K_EPSILON 1E-5f |
| |
| void mat44_fp_decompose_lup(mat44_fp_t LU, sizev4_t pivot) |
| { |
| const size_t N = 4; |
| size_t i, j, k; |
| |
| for (k = 0; k < N; ++k) { |
| fp_t max = fp_abs(LU[k][k]); |
| pivot[k] = k; |
| for (j = k + 1; j < N; ++j) { |
| const fp_t lu_jk = fp_abs(LU[j][k]); |
| if (max < lu_jk) { |
| max = lu_jk; |
| pivot[k] = j; |
| } |
| } |
| |
| if (pivot[k] != k) |
| mat44_fp_swap_rows(LU, k, pivot[k]); |
| |
| if (fp_abs(LU[k][k]) < FLOAT_TO_FP(K_EPSILON)) |
| continue; |
| |
| for (j = k + 1; j < N; ++j) |
| LU[k][j] = fp_div_dbz(LU[k][j], LU[k][k]); |
| |
| for (i = k + 1; i < N; ++i) |
| for (j = k + 1; j < N; ++j) |
| LU[i][j] -= fp_mul(LU[i][k], LU[k][j]); |
| } |
| } |
| |
| void mat44_fp_swap_rows(mat44_fp_t A, const size_t i, const size_t j) |
| { |
| const size_t N = 4; |
| size_t k; |
| |
| if (i == j) |
| return; |
| |
| for (k = 0; k < N; ++k) { |
| fp_t tmp = A[i][k]; |
| A[i][k] = A[j][k]; |
| A[j][k] = tmp; |
| } |
| } |
| |
| void mat44_fp_solve(mat44_fp_t A, fpv4_t x, const fpv4_t b, |
| const sizev4_t pivot) |
| { |
| const size_t N = 4; |
| fpv4_t b_copy; |
| size_t i, k; |
| |
| memcpy(b_copy, b, sizeof(fpv4_t)); |
| |
| for (k = 0; k < N; ++k) { |
| if (pivot[k] != k) { |
| fp_t tmp = b_copy[k]; |
| b_copy[k] = b_copy[pivot[k]]; |
| b_copy[pivot[k]] = tmp; |
| } |
| |
| x[k] = b_copy[k]; |
| for (i = 0; i < k; ++i) |
| x[k] -= fp_mul(x[i], A[k][i]); |
| x[k] = fp_div_dbz(x[k], A[k][k]); |
| } |
| |
| for (k = N; k-- > 0;) |
| for (i = k + 1; i < N; ++i) |
| x[k] -= fp_mul(x[i], A[k][i]); |
| } |