c1bc70b711
A lot of files were missing copyright field in the header and
the Blender Foundation contributed to them in a sense of bug
fixing and general maintenance.
This change makes it explicit that those files are at least
partially copyrighted by the Blender Foundation.
Note that this does not make it so the Blender Foundation is
the only holder of the copyright in those files, and developers
who do not have a signed contract with the foundation still
hold the copyright as well.
Another aspect of this change is using SPDX format for the
header. We already used it for the license specification,
and now we state it for the copyright as well, following the
FAQ:
https://reuse.software/faq/
127 lines
3.5 KiB
C
127 lines
3.5 KiB
C
/* SPDX-FileCopyrightText: 2015 Blender Foundation
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*
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* SPDX-License-Identifier: GPL-2.0-or-later */
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/** \file
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* \ingroup bli
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*/
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#include "MEM_guardedalloc.h"
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#include "BLI_math.h"
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#include "BLI_task.h"
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#include "BLI_utildefines.h"
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#include "BLI_strict_flags.h"
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/********************************** Covariance Matrices *********************************/
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typedef struct CovarianceData {
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const float *cos_vn;
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const float *center;
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float *r_covmat;
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float covfac;
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int n;
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int cos_vn_num;
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} CovarianceData;
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static void covariance_m_vn_ex_task_cb(void *__restrict userdata,
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const int a,
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const TaskParallelTLS *__restrict UNUSED(tls))
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{
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CovarianceData *data = userdata;
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const float *cos_vn = data->cos_vn;
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const float *center = data->center;
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float *r_covmat = data->r_covmat;
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const int n = data->n;
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const int cos_vn_num = data->cos_vn_num;
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int k;
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/* Covariance matrices are always symmetrical, so we can compute only one half of it,
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* and mirror it to the other half (at the end of the func).
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*
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* This allows using a flat loop of n*n with same results as imbricated one over half the matrix:
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*
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* for (i = 0; i < n; i++) {
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* for (j = i; j < n; j++) {
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* ...
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* }
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* }
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*/
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const int i = a / n;
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const int j = a % n;
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if (j < i) {
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return;
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}
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if (center) {
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for (k = 0; k < cos_vn_num; k++) {
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r_covmat[a] += (cos_vn[k * n + i] - center[i]) * (cos_vn[k * n + j] - center[j]);
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}
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}
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else {
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for (k = 0; k < cos_vn_num; k++) {
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r_covmat[a] += cos_vn[k * n + i] * cos_vn[k * n + j];
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}
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}
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r_covmat[a] *= data->covfac;
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if (j != i) {
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/* Mirror result to other half... */
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r_covmat[j * n + i] = r_covmat[a];
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}
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}
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void BLI_covariance_m_vn_ex(const int n,
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const float *cos_vn,
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const int cos_vn_num,
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const float *center,
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const bool use_sample_correction,
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float *r_covmat)
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{
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/* Note about that division: see https://en.wikipedia.org/wiki/Bessel%27s_correction.
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* In a nutshell, it must be 1 / (n - 1) for 'sample data', and 1 / n for 'population data'...
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*/
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const float covfac = 1.0f / (float)(use_sample_correction ? cos_vn_num - 1 : cos_vn_num);
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memset(r_covmat, 0, sizeof(*r_covmat) * (size_t)(n * n));
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CovarianceData data = {
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.cos_vn = cos_vn,
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.center = center,
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.r_covmat = r_covmat,
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.covfac = covfac,
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.n = n,
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.cos_vn_num = cos_vn_num,
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};
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TaskParallelSettings settings;
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BLI_parallel_range_settings_defaults(&settings);
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settings.use_threading = ((cos_vn_num * n * n) >= 10000);
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BLI_task_parallel_range(0, n * n, &data, covariance_m_vn_ex_task_cb, &settings);
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}
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void BLI_covariance_m3_v3n(const float (*cos_v3)[3],
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const int cos_v3_num,
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const bool use_sample_correction,
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float r_covmat[3][3],
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float r_center[3])
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{
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float center[3];
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const float mean_fac = 1.0f / (float)cos_v3_num;
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int i;
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zero_v3(center);
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for (i = 0; i < cos_v3_num; i++) {
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/* Applying mean_fac here rather than once at the end reduce compute errors... */
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madd_v3_v3fl(center, cos_v3[i], mean_fac);
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}
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if (r_center) {
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copy_v3_v3(r_center, center);
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}
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BLI_covariance_m_vn_ex(
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3, (const float *)cos_v3, cos_v3_num, center, use_sample_correction, (float *)r_covmat);
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}
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