wolffd@0: 
wolffd@0:   m  = mxGetM(prhs[0]);
wolffd@0:   n  = mxGetN(prhs[0]);
wolffd@0:   pr = mxGetPr(prhs[0]);
wolffd@0:   pi = mxGetPi(prhs[0]);
wolffd@0:   cmplx = (pi == NULL ? 0 : 1);
wolffd@0: 
wolffd@0:   /* Allocate space for sparse matrix. 
wolffd@0:    * NOTE:  Assume at most 20% of the data is sparse.  Use ceil
wolffd@0:    * to cause it to round up. 
wolffd@0:    */
wolffd@0: 
wolffd@0:   percent_sparse = 0.2;
wolffd@0:   nzmax = (int)ceil((double)m*(double)n*percent_sparse);
wolffd@0: 
wolffd@0:   plhs[0] = mxCreateSparse(m,n,nzmax,cmplx);
wolffd@0:   sr  = mxGetPr(plhs[0]);
wolffd@0:   si  = mxGetPi(plhs[0]);
wolffd@0:   irs = mxGetIr(plhs[0]);
wolffd@0:   jcs = mxGetJc(plhs[0]);
wolffd@0:     
wolffd@0:   /* Copy nonzeros. */
wolffd@0:   k = 0; 
wolffd@0:   isfull = 0;
wolffd@0:   for (j = 0; (j < n); j++) {
wolffd@0:     int i;
wolffd@0:     jcs[j] = k;
wolffd@0:     for (i = 0; (i < m); i++) {
wolffd@0:       if (IsNonZero(pr[i]) || (cmplx && IsNonZero(pi[i]))) {
wolffd@0: 
wolffd@0:         /* Check to see if non-zero element will fit in 
wolffd@0:          * allocated output array.  If not, increase
wolffd@0:          * percent_sparse by 10%, recalculate nzmax, and augment
wolffd@0:          * the sparse array.
wolffd@0:          */
wolffd@0:         if (k >= nzmax) {
wolffd@0:           int oldnzmax = nzmax;
wolffd@0:           percent_sparse += 0.1;
wolffd@0:           nzmax = (int)ceil((double)m*(double)n*percent_sparse);
wolffd@0: 
wolffd@0:           /* Make sure nzmax increases atleast by 1. */
wolffd@0:           if (oldnzmax == nzmax) 
wolffd@0:             nzmax++;
wolffd@0: 
wolffd@0:           mxSetNzmax(plhs[0], nzmax); 
wolffd@0:           mxSetPr(plhs[0], mxRealloc(sr, nzmax*sizeof(double)));
wolffd@0:           if (si != NULL)
wolffd@0:           mxSetPi(plhs[0], mxRealloc(si, nzmax*sizeof(double)));
wolffd@0:           mxSetIr(plhs[0], mxRealloc(irs, nzmax*sizeof(int)));
wolffd@0: 
wolffd@0:           sr  = mxGetPr(plhs[0]);
wolffd@0:           si  = mxGetPi(plhs[0]);
wolffd@0:           irs = mxGetIr(plhs[0]);
wolffd@0:         }
wolffd@0:         sr[k] = pr[i];
wolffd@0:         if (cmplx) {
wolffd@0:           si[k] = pi[i];
wolffd@0:         }
wolffd@0:         irs[k] = i;
wolffd@0:         k++;
wolffd@0:       }
wolffd@0:     }
wolffd@0:     pr += m;
wolffd@0:     pi += m;
wolffd@0:   }
wolffd@0:   jcs[n] = k;
wolffd@0: }