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mxGetIr (C and Fortran) - Get ir array of sparse matrix

C Syntax

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

Fortran Syntax

mwPointer mxGetIr(pm)
mwPointer pm

Arguments

pm

Pointer to a sparse mxArray

Returns

Pointer to the first element in the ir 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 usually means that an earlier call to mxCreateSparse failed.

Description

Use mxGetIr to obtain the starting address of the ir array. The ir array is an array of integers; the length of the ir array is typically nzmax values. For example, if nzmax equals 100, the ir array should contain 100 integers.

Each value in an ir array indicates a row (offset by 1) at which a nonzero element can be found. (The jc array is an index that indirectly specifies a column where nonzero elements can be found.)

For details on the ir and jc arrays, see mxSetIr and mxSetJc.

C Examples

See fulltosparse.c in the matlabroot/extern/examples/refbook folder .

Additional examples:

• explore.c in the matlabroot/extern/examples/mex folder

• mxsetdimensions.c and mxsetnzmax.c in the matlabroot/extern/examples/mx folder

See Also

mxGetJc, mxGetNzmax, mxSetIr, mxSetJc, mxSetNzmax

mxGetInf (C and Fortran)

mxGetJc (C and Fortran)

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