1 //------------------------------------------------------------------------------
2 // GB_spones_mex: like spones(A) in MATLAB but do not drop zeros on input
3 //------------------------------------------------------------------------------
4
5 // The MATLAB built-in function spones(A) has changed, of MATLAB R2019b.
6 // It now drops zeros on input. Prior versions converted them to 1 on output.
7 // The tests here use the old behavior, so this function replaces spones(A)
8 // with GB_spones_mex (A), which has the old behavior of spones.
9
10 #include "mex.h"
11 #include <string.h>
12
mexFunction(int nargout,mxArray * pargout[],int nargin,const mxArray * pargin[])13 void mexFunction
14 (
15 int nargout,
16 mxArray *pargout [ ],
17 int nargin,
18 const mxArray *pargin [ ]
19 )
20 {
21
22 //--------------------------------------------------------------------------
23 // check inputs
24 //--------------------------------------------------------------------------
25
26 if (nargin != 1 || nargout > 1 || !mxIsSparse (pargin [0]))
27 {
28 mexErrMsgTxt ("usage: C = GB_spones_mex (A), A must be sparse") ;
29 }
30
31 //--------------------------------------------------------------------------
32 // get the input matrix
33 //--------------------------------------------------------------------------
34
35 mwSize m = mxGetM (pargin [0]) ;
36 mwSize n = mxGetN (pargin [0]) ;
37 mwIndex *Ap = mxGetJc (pargin [0]) ;
38 mwIndex *Ai = mxGetIr (pargin [0]) ;
39 mwSize nz = Ap [n] ;
40
41 //--------------------------------------------------------------------------
42 // create the output matrix
43 //--------------------------------------------------------------------------
44
45 pargout [0] = mxCreateSparse (m, n, nz+1, mxREAL) ;
46 mwIndex *Cp = mxGetJc (pargout [0]) ;
47 mwIndex *Ci = mxGetIr (pargout [0]) ;
48 double *Cx = mxGetDoubles (pargout [0]) ;
49
50 memcpy (Cp, Ap, (n+1) * sizeof (mwIndex)) ;
51 memcpy (Ci, Ai, nz * sizeof (mwIndex)) ;
52 for (mwSize p = 0 ; p < nz ; p++)
53 {
54 Cx [p] = 1 ;
55 }
56 }
57
58