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- /* LPC_and_LFCC.cpp
- *
- * Copyright (C) 1994-2018 David Weenink
- *
- * This code 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 2 of the License, or (at
- * your option) any later version.
- *
- * This code 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 this work. If not, see <http://www.gnu.org/licenses/>.
- */
- /*
- djmw 20020812 GPL header
- djmw 20030205 Latest modifiation
- */
- #include "LPC_and_LFCC.h"
- #include "NUM2.h"
- void LPC_Frame_into_CC_Frame (LPC_Frame me, CC_Frame thee) {
- double *c = thy c, *a = my a.at;
- thy c0 = 0.5 * log (my gain);
- if (my nCoefficients < 1) {
- return;
- }
- c [1] = -a [1];
- for (integer n = 2; n <= std::min ((integer) my nCoefficients, thy numberOfCoefficients); n ++) {
- double s = 0;
- for (integer k = 1; k < n; k ++) {
- s += a [k] * c [n - k] * (n - k);
- }
- c [n] = -a [n] - s / n;
- }
- for (integer n = my nCoefficients + 1; n <= thy numberOfCoefficients; n ++) {
- double s = 0;
- for (integer k = 1; k <= my nCoefficients; k ++) {
- s += a [k] * c [n - k] * (n - k);
- }
- c [n] = - s / n;
- }
- }
- void CC_Frame_into_LPC_Frame (CC_Frame me, LPC_Frame thee) {
- integer n = std::min (my numberOfCoefficients, (integer) thy nCoefficients);
- thy gain = exp (2.0 * my c0);
- if (n < 1) return;
- thy a [1] = - my c [1];
- for (integer i = 2; i <= n; i ++) {
- longdouble ai = my c [i] * i;
- for (integer j = 1; j < i; j ++) {
- ai += thy a [j] * my c [i - j] * (i - j);
- }
- thy a [i] = -ai / i;
- }
- }
- autoLFCC LPC_to_LFCC (LPC me, integer numberOfCoefficients) {
- try {
- if (numberOfCoefficients < 1) {
- numberOfCoefficients = my maxnCoefficients;
- }
- autoLFCC thee = LFCC_create (my xmin, my xmax, my nx, my dx, my x1, numberOfCoefficients, 0, 0.5 / my samplingPeriod);
- for (integer i = 1; i <= my nx; i ++) {
- CC_Frame_init (& thy frame [i], numberOfCoefficients);
- LPC_Frame_into_CC_Frame (& my d_frames [i], & thy frame [i]);
- }
- return thee;
- } catch (MelderError) {
- Melder_throw (me, U": no LFCC created.");
- }
- }
- autoLPC LFCC_to_LPC (LFCC me, integer numberOfCoefficients) {
- try {
- if (numberOfCoefficients < 1) {
- numberOfCoefficients = my maximumNumberOfCoefficients;
- }
- numberOfCoefficients = std::min (numberOfCoefficients, my maximumNumberOfCoefficients);
- autoLPC thee = LPC_create (my xmin, my xmax, my nx, my dx, my x1, numberOfCoefficients, 0.5 / my fmax);
- for (integer i = 1; i <= my nx; i ++) {
- LPC_Frame_init (& thy d_frames [i], numberOfCoefficients);
- CC_Frame_into_LPC_Frame (& my frame [i], & thy d_frames [i]);
- }
- return thee;
- } catch (MelderError) {
- Melder_throw (me, U": no LPC created.");
- }
- }
- /* End of file LPC_and_LFCC.cpp */
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