mxGetJc (C and Fortran)

Sparse matrix JC array

C Syntax

#include "matrix.h"
mwIndex *mxGetJc(const mxArray *pm);

Fortran Syntax

#include "fintrf.h"
mwPointer mxGetJc(pm)
mwPointer pm

Arguments

pm

Pointer to a sparse mxArray

Returns

Pointer to the first element in the jc array, if successful, and NULL in C (0 in Fortran) otherwise. Possible causes of failure include

• Specifying a full (nonsparse) mxArray.

• Specifying a value for pm that is NULL in C (0 in Fortran). This failure usually means that an earlier call to mxCreateSparse failed.

Description

Use mxGetJc to obtain the starting address of the jc array. The jc array is an integer array having n+1 elements, where n is the number of columns in the sparse mxArray. The values in the jc array indirectly indicate columns containing nonzero elements. For a detailed explanation of the jc array, see mxSetJc.

Examples

See these examples in matlabroot/extern/examples/refbook:

• fulltosparse.c

• fulltosparse.F

See these examples in matlabroot/extern/examples/mx:

• mxgetnzmax.c

• mxsetdimensions.c

• mxsetnzmax.c

See these examples in matlabroot/extern/examples/mex:

• explore.c