mxGetJc (MATLAB Application Program Interface)

Get the jc array of a sparse matrix

C Syntax

#include "matrix.h"
int *mxGetJc(const mxArray *array_ptr);

Arguments

array_ptr
Pointer to a sparse mxArray.

Returns

A pointer to the first element in the jc array, if successful; otherwise, returns NULL. The most likely cause of failure is specifying an array_ptr that points to a full (nonsparse) mxArray.

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

For additional examples, see explore.c in the mex subdirectory of the examples directory; see mxgetnzmax.c, mxsetdimensions.c, and mxsetnzmax.c in the mx subdirectory of the examples directory.