ref: c31b589dcbb769b010af802724a2303eeca7899a
dir: /src/spectral/statistics.c/
/* Copyright (C) 2007-2009 Paul Brossier <piem@aubio.org> This file is part of aubio. aubio is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. aubio is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with aubio. If not, see <http://www.gnu.org/licenses/>. */ #include "aubio_priv.h" #include "cvec.h" #include "spectral/specdesc.h" void aubio_specdesc_centroid (aubio_specdesc_t * o, const cvec_t * spec, fvec_t * desc); void aubio_specdesc_spread (aubio_specdesc_t * o, const cvec_t * spec, fvec_t * desc); void aubio_specdesc_skewness (aubio_specdesc_t * o, const cvec_t * spec, fvec_t * desc); void aubio_specdesc_kurtosis (aubio_specdesc_t * o, const cvec_t * spec, fvec_t * desc); void aubio_specdesc_slope (aubio_specdesc_t * o, const cvec_t * spec, fvec_t * desc); void aubio_specdesc_decrease (aubio_specdesc_t * o, const cvec_t * spec, fvec_t * desc); void aubio_specdesc_rolloff (aubio_specdesc_t * o, const cvec_t * spec, fvec_t * desc); smpl_t cvec_sum (const cvec_t * s); smpl_t cvec_mean (const cvec_t * s); smpl_t cvec_centroid (const cvec_t * s); smpl_t cvec_moment (const cvec_t * s, uint_t moment); smpl_t cvec_sum (const cvec_t * s) { uint_t j; smpl_t tmp = 0.0; for (j = 0; j < s->length; j++) { tmp += s->norm[j]; } return tmp; } smpl_t cvec_mean (const cvec_t * s) { return cvec_sum (s) / (smpl_t) (s->length); } smpl_t cvec_centroid (const cvec_t * spec) { smpl_t sum = 0., sc = 0.; uint_t j; sum = cvec_sum (spec); if (sum == 0.) { return 0.; } else { for (j = 0; j < spec->length; j++) { sc += (smpl_t) j *spec->norm[j]; } return sc / sum; } } smpl_t cvec_moment (const cvec_t * spec, uint_t order) { smpl_t sum = 0., centroid = 0., sc = 0.; uint_t j; sum = cvec_sum (spec); if (sum == 0.) { return 0.; } else { centroid = cvec_centroid (spec); for (j = 0; j < spec->length; j++) { sc += (smpl_t) POW(j - centroid, order) * spec->norm[j]; } return sc / sum; } } void aubio_specdesc_centroid (aubio_specdesc_t * o UNUSED, const cvec_t * spec, fvec_t * desc) { desc->data[0] = cvec_centroid (spec); } void aubio_specdesc_spread (aubio_specdesc_t * o UNUSED, const cvec_t * spec, fvec_t * desc) { desc->data[0] = cvec_moment (spec, 2); } void aubio_specdesc_skewness (aubio_specdesc_t * o UNUSED, const cvec_t * spec, fvec_t * desc) { smpl_t spread; spread = cvec_moment (spec, 2); if (spread == 0) { desc->data[0] = 0.; } else { desc->data[0] = cvec_moment (spec, 3); desc->data[0] /= POW ( SQRT (spread), 3); } } void aubio_specdesc_kurtosis (aubio_specdesc_t * o UNUSED, const cvec_t * spec, fvec_t * desc) { smpl_t spread; spread = cvec_moment (spec, 2); if (spread == 0) { desc->data[0] = 0.; } else { desc->data[0] = cvec_moment (spec, 4); desc->data[0] /= SQR (spread); } } void aubio_specdesc_slope (aubio_specdesc_t * o UNUSED, const cvec_t * spec, fvec_t * desc) { uint_t j; smpl_t norm = 0, sum = 0.; // compute N * sum(j**2) - sum(j)**2 for (j = 0; j < spec->length; j++) { norm += j*j; } norm *= spec->length; // sum_0^N(j) = length * (length + 1) / 2 norm -= SQR( (spec->length) * (spec->length - 1.) / 2. ); sum = cvec_sum (spec); desc->data[0] = 0.; if (sum == 0.) { return; } else { for (j = 0; j < spec->length; j++) { desc->data[0] += j * spec->norm[j]; } desc->data[0] *= spec->length; desc->data[0] -= sum * spec->length * (spec->length - 1) / 2.; desc->data[0] /= norm; desc->data[0] /= sum; } } void aubio_specdesc_decrease (aubio_specdesc_t *o UNUSED, const cvec_t * spec, fvec_t * desc) { uint_t j; smpl_t sum; sum = cvec_sum (spec); desc->data[0] = 0; if (sum == 0.) { return; } else { sum -= spec->norm[0]; for (j = 1; j < spec->length; j++) { desc->data[0] += (spec->norm[j] - spec->norm[0]) / j; } desc->data[0] /= sum; } } void aubio_specdesc_rolloff (aubio_specdesc_t *o UNUSED, const cvec_t * spec, fvec_t *desc) { uint_t j; smpl_t cumsum, rollsum; cumsum = 0.; rollsum = 0.; for (j = 0; j < spec->length; j++) { cumsum += SQR (spec->norm[j]); } if (cumsum == 0) { desc->data[0] = 0.; } else { cumsum *= 0.95; j = 0; while (rollsum < cumsum) { rollsum += SQR (spec->norm[j]); j++; } desc->data[0] = j; } }