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/*
RES = innerProd(MAT);
Computes mat'*mat
Odelia Schwartz, 8/97.
*/
#define V4_COMPAT
#include <matrix.h>
#include <stdio.h>
#include <ctype.h>
#include <math.h>
#include <strings.h>
#include <stdlib.h>
void mexFunction(int nlhs, /* Num return vals on lhs */
mxArray *plhs[], /* Matrices on lhs */
int nrhs, /* Num args on rhs */
const mxArray *prhs[] /* Matrices on rhs */
)
{
register double *res, *mat, tmp;
register int len, wid, i, k, j, jlen, ilen, imat, jmat;
mxArray *arg;
/* get matrix input argument */
/* should be matrix in which num rows >= num columns */
arg=prhs[0];
mat= mxGetPr(arg);
len = (int) mxGetM(arg);
wid = (int) mxGetN(arg);
if ( wid > len )
printf("innerProd: Warning: width %d is greater than length %d.\n",wid,len);
plhs[0] = (mxArray *) mxCreateDoubleMatrix(wid,wid,mxREAL);
if (plhs[0] == NULL)
mexErrMsgTxt(sprintf("Error allocating %dx%d result matrix",wid,wid));
res = mxGetPr(plhs[0]);
for(i=0, ilen=0; i<wid; i++, ilen+=len)
{
for(j=i, jlen=ilen; j<wid; j++, jlen+=len)
{
tmp = 0.0;
for(k=0, imat=ilen, jmat=jlen; k<len; k++, imat++, jmat++)
tmp += mat[imat]*mat[jmat];
res[i*wid+j] = tmp;
res[j*wid+i] = tmp;
}
}
return;
}
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