wolffd@0: #include <stdio.h>
wolffd@0: #include "mex.h"
wolffd@0: 
wolffd@0: /*
wolffd@0: out = colop(M, v)
wolffd@0: 
wolffd@0: Apply binary operator to a vector v and to each column of M in turn
wolffd@0: to produce a matrix the same size as M.
wolffd@0: 
wolffd@0: This is equivalent to
wolffd@0: 
wolffd@0: out = zeros(size(M));
wolffd@0: for col=1:size(M,2)
wolffd@0:   out(:,col) = op(M(:,col), v);
wolffd@0: end
wolffd@0: 
wolffd@0: The code needs to be modified for each different operator 'op'.
wolffd@0: eg op = '.*'
wolffd@0: 
wolffd@0: In vectorized form:
wolffd@0: 
wolffd@0: out = M .* repmat(v(:), 1, size(M,2))
wolffd@0: 
wolffd@0: (This function was formerly called repmat_and_mult.c)
wolffd@0: 
wolffd@0: */
wolffd@0: 
wolffd@0: /* M(i,j) = M(i + nrows*j) since Matlab uses Fortran layout. */
wolffd@0: 
wolffd@0:  
wolffd@0: #define INMAT(i,j) M[(i)+nrows*(j)]
wolffd@0: #define OUTMAT(i,j) out[(i)+nrows*(j)]
wolffd@0: 
wolffd@0: void mexFunction(
wolffd@0:                  int nlhs,       mxArray *plhs[],
wolffd@0:                  int nrhs, const mxArray *prhs[]
wolffd@0: 		 )
wolffd@0: {
wolffd@0:   double *out, *M, *v;
wolffd@0:   int nrows, ncols, r, c;
wolffd@0:   
wolffd@0:   /* read the input args */
wolffd@0:   M = mxGetPr(prhs[0]);
wolffd@0:   nrows = mxGetM(prhs[0]);
wolffd@0:   ncols = mxGetN(prhs[0]);
wolffd@0: 
wolffd@0:   v = mxGetPr(prhs[1]);
wolffd@0: 
wolffd@0:   plhs[0] = mxCreateDoubleMatrix(nrows, ncols, mxREAL);
wolffd@0:   out = mxGetPr(plhs[0]); 
wolffd@0: 
wolffd@0:   for (c=0; c < ncols; c++) {
wolffd@0:     for (r=0; r < nrows; r++) {
wolffd@0:       OUTMAT(r,c) = INMAT(r,c) * v[r]; 
wolffd@0:       /* printf("r=%d, c=%d, M=%f, v=%f\n", r, c, INMAT(r,c), v[r]);  */
wolffd@0:     }
wolffd@0:   }
wolffd@0: 
wolffd@0: }
wolffd@0: 
wolffd@0: 
wolffd@0: