MATLAB Application Program Interface Reference

True if a sparse mxArray

#include "matrix.h"
bool mxIsSparse(const mxArray *array_ptr);

Arguments

array_ptr

Pointer to an mxArray.

Returns

1 if array_ptr points to a sparse mxArray; otherwise, returns 0. A return value of 0 means that array_ptr points to a full mxArray or that array_ptr does not point to a legal mxArray.

Description

Use mxIsSparse to determine if array_ptr points to a sparse mxArray. Many routines (for example, mxGetIr and mxGetJc) require a sparse mxArray as input.

Examples

Consider a MEX-file that requires the first input argument to be a sparse mxArray. The first part of the MEX-file might be

void
mexFunction(int nlhs,mxArray *plhs[],int nrhs,const mxArray 
*prhs[])
{
   if (mxIsSparse(prhs[0])) { 
     /* Yes, this is a sparse mxArray. */
   ...
   }
   else
     mexErrMsgTxt("First argument must be a sparse array.");

For an additional example, see mxIsSparse.c in the mx subdirectory of the examples directory.