annotate Problems/private/sprow.c @ 39:8f734534839a

(none)
author idamnjanovic
date Mon, 14 Mar 2011 15:35:01 +0000
parents 51b76c31c93d
children
rev   line source
idamnjanovic@15 1 /**************************************************************************
idamnjanovic@15 2 *
idamnjanovic@15 3 * File name: sprow.c
idamnjanovic@15 4 *
idamnjanovic@15 5 * Ron Rubinstein
idamnjanovic@15 6 * Computer Science Department
idamnjanovic@15 7 * Technion, Haifa 32000 Israel
idamnjanovic@15 8 * ronrubin@cs
idamnjanovic@15 9 *
idamnjanovic@15 10 * Last Updated: 24.8.2009
idamnjanovic@15 11 *
idamnjanovic@15 12 *************************************************************************/
idamnjanovic@15 13
idamnjanovic@15 14
idamnjanovic@15 15 #include "mex.h"
idamnjanovic@15 16 #include "mexutils.h"
idamnjanovic@15 17
idamnjanovic@15 18
idamnjanovic@15 19 /* Input Arguments */
idamnjanovic@15 20
idamnjanovic@15 21 #define A_IN prhs[0]
idamnjanovic@15 22 #define J_IN prhs[1]
idamnjanovic@15 23
idamnjanovic@15 24
idamnjanovic@15 25 /* Output Arguments */
idamnjanovic@15 26
idamnjanovic@15 27 #define X_OUT plhs[0]
idamnjanovic@15 28 #define ID_OUT plhs[1]
idamnjanovic@15 29
idamnjanovic@15 30
idamnjanovic@15 31 void mexFunction(int nlhs, mxArray *plhs[],
idamnjanovic@15 32 int nrhs, const mxArray*prhs[])
idamnjanovic@15 33
idamnjanovic@15 34 {
idamnjanovic@15 35 double *pr, *x, *id, rowid;
idamnjanovic@15 36 mwIndex *ir, *jc;
idamnjanovic@15 37 mwSize m, n;
idamnjanovic@15 38 mwIndex i, j, k, l, rowlen;
idamnjanovic@15 39
idamnjanovic@15 40 if (nrhs != 2) {
idamnjanovic@15 41 mexErrMsgTxt("GETSPROW requires two input arguments.");
idamnjanovic@15 42 } else if (nlhs > 2) {
idamnjanovic@15 43 mexErrMsgTxt("Too many output arguments.");
idamnjanovic@15 44 }
idamnjanovic@15 45
idamnjanovic@15 46 checkmatrix(A_IN, "GETSPROW", "A");
idamnjanovic@15 47 checksparse(A_IN, "GETSPROW", "A");
idamnjanovic@15 48 checkscalar(J_IN, "GETSPROW", "J");
idamnjanovic@15 49
idamnjanovic@15 50 m = mxGetM(A_IN);
idamnjanovic@15 51 n = mxGetN(A_IN);
idamnjanovic@15 52
idamnjanovic@15 53 rowid = mxGetScalar(J_IN);
idamnjanovic@15 54 if (rowid < 0) {
idamnjanovic@15 55 mexErrMsgTxt("Invalid row index.");
idamnjanovic@15 56 }
idamnjanovic@15 57 j = (mwIndex)(rowid + 1e-2);
idamnjanovic@15 58 if (j<1 || j>m) {
idamnjanovic@15 59 mexErrMsgTxt("Row index is out of range.");
idamnjanovic@15 60 }
idamnjanovic@15 61 j--;
idamnjanovic@15 62
idamnjanovic@15 63 pr = mxGetPr(A_IN);
idamnjanovic@15 64 ir = mxGetIr(A_IN);
idamnjanovic@15 65 jc = mxGetJc(A_IN);
idamnjanovic@15 66
idamnjanovic@15 67 /* Determine length of row */
idamnjanovic@15 68 rowlen = 0;
idamnjanovic@15 69 for (i=0; i<jc[n]; ++i) {
idamnjanovic@15 70 rowlen += (ir[i]==j);
idamnjanovic@15 71 }
idamnjanovic@15 72
idamnjanovic@15 73 /* Allocate output parameters */
idamnjanovic@15 74 X_OUT = mxCreateDoubleMatrix(1, rowlen, mxREAL);
idamnjanovic@15 75 ID_OUT = mxCreateDoubleMatrix(1, rowlen, mxREAL);
idamnjanovic@15 76
idamnjanovic@15 77 x = mxGetPr(X_OUT);
idamnjanovic@15 78 id = mxGetPr(ID_OUT);
idamnjanovic@15 79
idamnjanovic@15 80 /* Compute j-th row */
idamnjanovic@15 81 k=0;
idamnjanovic@15 82 for (l=1; l<=n; ++l) {
idamnjanovic@15 83 i = jc[l-1];
idamnjanovic@15 84 while (i<jc[l] && ir[i]<j) {
idamnjanovic@15 85 i++;
idamnjanovic@15 86 }
idamnjanovic@15 87 if (i<jc[l] && ir[i]==j) {
idamnjanovic@15 88 x[k] = pr[i];
idamnjanovic@15 89 id[k] = l;
idamnjanovic@15 90 k++;
idamnjanovic@15 91 }
idamnjanovic@15 92 }
idamnjanovic@15 93
idamnjanovic@15 94 }