/* -*- C -*- */
/*
 * Copyright (c) 2003 Jindrich Novy (jnovy@users.sf.net)
 *
 * This program 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 program 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 program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#include <assert.h>
#include <math.h>
#include <stdio.h>
#include <string.h>

#define sqr(x) (x)*(x)

FCE_FLOAT convol_gauss( FCE_FLOAT xx, FCE_FLOAT magn, FCE_FLOAT x ) {
	FCE_FLOAT sigma_sqr = -log(magn)*xx*xx/(log(magn)*log(magn));
	return exp(-x*x/sigma_sqr);
}

/* Convolution vector order (ord>=3) have to be odd. */
void init_lookup_vector( FCE_FLOAT *vector, int ord, FCE_FLOAT xx, FCE_FLOAT magn ) {
	int x, ord2 = ord>>1;
	FCE_FLOAT r;
	FCE_FLOAT sigma_sqr = -log(magn)*xx*xx/(log(magn)*log(magn));
#ifdef FCE_DEBUG
	FILE *f = fopen("vector.txt","wt");
#endif

	for ( x=0; x<ord; x++ ) {
		r = sqr(x-ord2);
		vector[x] = exp(-r/sigma_sqr);
#ifdef FCE_DEBUG
		fprintf(f, "%1.5f\n", vector[x]);
#endif
	}
#ifdef FCE_DEBUG
	fprintf(f, "\n");
	fclose(f);
#endif
}

/* Interval weighting function lookup table initialization */
void init_lookup_iweight( FCE_FLOAT *l, int s, FCE_FLOAT xp, FCE_FLOAT vp, FCE_FLOAT xn, FCE_FLOAT vn ) {
	int x;
	FCE_FLOAT sigmap = sqrt(-log(vp))*xp/log(vp);
	FCE_FLOAT sigman = sqrt(-log(vn))*xn/log(vn);
#ifdef FCE_DEBUG
	FILE *f;

	assert( f=fopen("lookup.txt","wt") );
#endif

	for ( x=s>>1; x<s; x++ ) {
		l[x] = exp(-sqr((x-(s>>1))/sigmap));
	}

	for ( x=(s>>1)-1; x>=0; x-- ) {
		l[x] = exp(-sqr((x-(s>>1))/sigman));
	}

#ifdef FCE_DEBUG
	for ( x=0; x<s; x++ ) {
		fprintf(f, "%3d\t%f\n", x, l[x]);
	}

	fclose( f );
#endif
}

#undef sqr