/* ====================================================================
 * Copyright (c) 1999-2001 Carnegie Mellon University.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * This work was supported in part by funding from the Defense Advanced 
 * Research Projects Agency and the National Science Foundation of the 
 * United States of America, and the CMU Sphinx Speech Consortium.
 *
 * THIS SOFTWARE IS PROVIDED BY CARNEGIE MELLON UNIVERSITY ``AS IS'' AND 
 * ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY
 * NOR ITS EMPLOYEES BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 * ====================================================================
 *
 */
/* norm.c - feature normalization
 * 
 * HISTORY
 * 
 * 20-Aug-98	M K Ravishankar (rkm@cs.cmu.edu) at Carnegie Mellon University
 * 		Extended normalization to C0.
 * 
 |------------------------------------------------------------*
 | $Header: /cvsroot/cmusphinx/sphinx2/src/libsphinx2/norm.c,v 1.6 2001/12/11 00:24:48 lenzo Exp $
 |------------------------------------------------------------*
 | Description
 |	norm_mean()	- compute the mean of the input vectors
 |			  and then subtract the mean from the
 |			  input vectors. Leave coefficient 0
 |			  untouched.
 */

#include <stdlib.h>

#include <s2types.h>

#ifdef DEBUG
#define dprintf(x)	printf x
#else
#define dprintf(x)
#endif

void
norm_mean(float	*vec,		/* the data */
	  int32	nvec,		/* number of vectors (frames) */
	  int32	veclen)		/* number of elements (coefficients) per vector */
{
    static double      *mean = 0;
    float              *data;
    int32               i, f;

    if (mean == 0)
	mean = (double *) calloc (veclen, sizeof (double));

    for (i = 0; i < veclen; i++)
	mean[i] = 0.0;

    /*
     * Compute the sum
     */
    for (data = vec, f = 0; f < nvec; f++, data += veclen) {
	for (i = 0; i < veclen; i++)
	    mean[i] += data[i];
    }

    /*
     * Compute the mean
     */
    dprintf(("Mean Vector\n"));
    for (i = 0; i < veclen; i++) {
	mean[i] /= nvec;
	dprintf(("[%d]%.3f, ", i, mean[i]));
    }
    dprintf(("\n"));
    
    /*
     * Normalize the data
     */
    for (data = vec, f = 0; f < nvec; f++, data += veclen) {
	for (i = 0; i < veclen; i++)
	    data[i] -= mean[i];
    }
}