Chris@0: /*
Chris@0:   copyright (C) 2012 I. Irigaray, M. Rocamora
Chris@0: 
Chris@0:   This program is free software: you can redistribute it and/or modify
Chris@0:   it under the terms of the GNU General Public License as published by
Chris@0:   the Free Software Foundation, either version 3 of the License, or
Chris@0:   (at your option) any later version.
Chris@0: 
Chris@0:   This program is distributed in the hope that it will be useful,
Chris@0:   but WITHOUT ANY WARRANTY; without even the implied warranty of
Chris@0:   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
Chris@0:   GNU General Public License for more details.
Chris@0: 
Chris@0:   You should have received a copy of the GNU General Public License
Chris@0:   along with this program.  If not, see <http://www.gnu.org/licenses/>.
Chris@8: */
Chris@0: 
Chris@0: 
Chris@0: #include "FChTransformUtils.h"
Chris@29: 
Chris@29: #define _USE_MATH_DEFINES
Chris@29: 
Chris@0: #include <math.h>
Chris@0: 
Chris@14: void
Chris@14: Utils::cumtrapz(const double *x, const double *y, int N, double *accum)
Chris@0: /*Trapezoidal Integrator: 1/2(b-a)(F(a)+F(b))*/
Chris@0: {
Chris@8:     accum[0]=0.0;
Chris@10:     for (int i = 1; i < N; i++) {
Chris@8:         accum[i]=accum[i-1]+0.5*(x[i]-x[i-1])*(y[i]+y[i-1]);
Chris@8:     }
Chris@0: }
Chris@0: 
Chris@0: 
Chris@14: void
Chris@14: Utils::interp1(const double *x1, const double *y1, int N1, const double *x2, double *y2, int N2){
Chris@0: /*1-D linear interpolation*/
Chris@0: 
Chris@10:     for (int i = 0; i < N2; i++) {
Chris@8:         /*Smaller or equal than the smallest, or larger or equal than the largest.*/
Chris@8:         if ( x2[i] <= x1[0] ) {
Chris@8:             y2[i] = y1[0];
Chris@8:         } else if ( x2[i] >= x1[N1-1] ) {
Chris@8:             y2[i] = y1[N1-1];
Chris@8:         } else {
Chris@8:             /*Search every value of x2 in x1*/
Chris@10:             int j = 1;
Chris@10:             int salir = 0;
Chris@8:             while ((j<N1)&&(!salir)) {			
Chris@8:                 if ( x2[i] <= x1[j] ) {
Chris@8:                     y2[i] = y1[j-1] + ( ( y1[j] - y1[j-1] )*(x2[i] - x1[j-1] ) )/ ( x1[j] - x1[j-1] );
Chris@8:                     salir = 1;
Chris@8:                 } // if
Chris@8:                 j++;
Chris@8:             } // for
Chris@8:         } // else
Chris@8:     } // for
Chris@0: 
Chris@0: }
Chris@0: 
Chris@14: void
Chris@14: Utils::hanning_window(double *p_window, int n, bool normalize) {
Chris@0: 
Chris@8:     double accum=0;
Chris@10:     for (int i = 0; i < n; i++) {
Chris@0:         p_window[i] = 0.5*(1.0-cos(2*M_PI*(double)(i+1)/((double)n+1.0)));
Chris@0:         accum += p_window[i];
Chris@0:     }
Chris@8:     if (normalize) {
Chris@10:     	for (int i = 0; i < n; i++) { //window normalization
Chris@8:             p_window[i] = p_window[i]/accum;
Chris@0:     	}
Chris@8:     }
Chris@0: 
Chris@0: }