111 lines
3.4 KiB
C
111 lines
3.4 KiB
C
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/******************************************************************
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* mexProd2sp: compute A*B, where A*B are sparse
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*
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* P = mexProd2sp(A,B,nnz), where P = A*B.
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*
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* output: P is sparse.
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*
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* SDPT3: version 3.0
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* Copyright (c) 1997 by
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* K.C. Toh, M.J. Todd, R.H. Tutuncu
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* Last Modified: 2 Feb 01
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******************************************************************/
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#include <mex.h>
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#include <math.h>
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#include <matrix.h>
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#include "header.h"
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/**********************************************************
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* A, B sparse.
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* A = mxn, B = nxp
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**********************************************************/
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void prodsp(int m, int n, int p,
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double *A, mwIndex *irA, mwIndex *jcA,
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double *B, mwIndex *irB, mwIndex *jcB,
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double *P, mwIndex *irP, mwIndex *jcP, double *Btmp)
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{ int j, k, r, t, Astart, Aend, Bstart, Bend, idx, count;
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double tmp;
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count = 0; jcP[0] = 0;
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for (j=0; j<p; j++) {
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Bstart = jcB[j]; Bend = jcB[j+1];
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for (k=Bstart; k<Bend; k++) {
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tmp = B[k];
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r = irB[k];
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Astart = jcA[r]; Aend = jcA[r+1];
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for (t=Astart; t<Aend; t++) {
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idx = irA[t];
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Btmp[idx] += A[t]*tmp;
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}
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}
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for (k=0; k<m; k++) {
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tmp = Btmp[k];
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if (tmp != 0) {
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P[count] = tmp;
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irP[count] = k;
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count++;
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Btmp[k] = 0;
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}
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}
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jcP[j+1]=count;
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}
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return;
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}
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/**********************************************************
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*
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**********************************************************/
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void mexFunction(int nlhs, mxArray *plhs[],
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int nrhs, const mxArray *prhs[] )
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{
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double *A, *B, *P;
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mwIndex *irA, *jcA, *irB, *jcB, *irP, *jcP;
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double *Btmp;
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int nnz, m1, n1, m2, n2, mlist, nlist, isspA, isspB, k;
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/* Check for proper number of arguments */
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if (nrhs != 3){
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mexErrMsgTxt("mexProd2sp: requires 3 input arguments."); }
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else if (nlhs > 2){
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mexErrMsgTxt("mexProd2sp: requires 1 output argument."); }
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/***********************************************/
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A = mxGetPr(prhs[0]);
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isspA = mxIsSparse(prhs[0]);
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m1 = mxGetM(prhs[0]);
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n1 = mxGetN(prhs[0]);
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if (!isspA) {
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mexErrMsgTxt("mexProd2sp: A must be sparse"); }
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if (isspA) { irA = mxGetIr(prhs[0]);
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jcA = mxGetJc(prhs[0]); }
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B = mxGetPr(prhs[1]);
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isspB = mxIsSparse(prhs[1]);
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m2 = mxGetM(prhs[1]);
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n2 = mxGetN(prhs[1]);
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if (!isspB) {
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mexErrMsgTxt("mexProd2sp: B must be sparse"); }
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if (isspB) { irB = mxGetIr(prhs[1]);
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jcB = mxGetJc(prhs[1]); }
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if (n1!=m2) {
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mexErrMsgTxt("mexProd2sp: A, B are not compatible"); }
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nnz = (int) *mxGetPr(prhs[2]);
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plhs[0] = mxCreateSparse(m1,n2,nnz,mxREAL);
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P = mxGetPr(plhs[0]);
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irP = mxGetIr(plhs[0]);
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jcP = mxGetJc(plhs[0]);
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/**********************************************
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* Do the actual computations in a subroutine
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**********************************************/
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Btmp = mxCalloc(m1,sizeof(double));
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prodsp(m1,n1,n2,A,irA,jcA,B,irB,jcB,P,irP,jcP,Btmp);
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if (isspB) { mxFree(Btmp); }
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return;
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}
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/**********************************************************/
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