MATLAB^®

mxCreateSparse (C and Fortran) - Create 2-D unpopulated sparse `mxArray`

C Syntax

#include "matrix.h"
mxArray *mxCreateSparse(mwSize m, mwSize n, mwSize nzmax, 
         mxComplexity ComplexFlag);

Fortran Syntax

mwPointer mxCreateSparse(m, n, nzmax, ComplexFlag)
mwSize m, n, nzmax
integer*4 ComplexFlag

Arguments

m: The desired number of rows
n: The desired number of columns
nzmax: The number of elements that mxCreateSparse should allocate to hold the pr, ir, and, if ComplexFlag is mxCOMPLEX in C (1 in Fortran), pi arrays. Set the value of nzmax to be greater than or equal to the number of nonzero elements you plan to put into the mxArray, but make sure that nzmax is less than or equal to m*n.
ComplexFlag: If the mxArray you are creating is to contain imaginary data, set ComplexFlag to mxCOMPLEX in C (1 in Fortran). Otherwise, set ComplexFlag to mxREAL in C (0 in Fortran).

Returns

A pointer to the created sparse double mxArray if successful, and NULL in C (0 in Fortran) otherwise. The most likely reason for failure is insufficient free heap space. If that happens, try reducing nzmax, m, or n.

Description

Call mxCreateSparse to create an unpopulated sparse double mxArray. The returned sparse mxArray contains no sparse information and cannot be passed as an argument to any MATLAB^® sparse functions. To make the returned sparse mxArray useful, you must initialize the pr, ir, jc, and (if it exists) pi arrays.

mxCreateSparse allocates space for

A pr array of length nzmax.
A pi array of length nzmax, but only if ComplexFlag is mxCOMPLEX in C (1 in Fortran).
An ir array of length nzmax.
A jc array of length n+1.

When you finish using the sparse mxArray, call mxDestroyArray to reclaim all its heap space.

C Examples

See fulltosparse.c in the refbook subdirectory of the examples directory.

mxCreateSparse (C and Fortran) - Create 2-D unpopulated sparse mxArray