| External Interfaces/API Reference | |
Set the storage space for nonzero elements
Fortran Syntax
Arguments
pm
Pointer to a sparse mxArray.
nzmax
The number of elements that mxCreateSparse should allocate to hold the arrays pointed to by ir, pr, and pi (if it exists). Set nzmax greater than or equal to the number of nonzero elements in the mxArray, but set it to be less than or equal to the number of rows times the number of columns. If you specify an nzmax value of 0, mxSetNzmax sets the value of nzmax to 1.
Description
Use mxSetNzmax to assign a new value to the nzmax field of the specified sparse mxArray. The nzmax field holds the maximum possible number of nonzero elements in the sparse mxArray.
The number of elements in the ir, pr, and pi (if it exists) arrays must be equal to nzmax. Therefore, after calling mxSetNzmax, you must change the size of the ir, pr, and pi arrays.
How big should nzmax be? One thought is that you set nzmax equal to or slightly greater than the number of nonzero elements in a sparse mxArray. This approach conserves precious heap space. Another technique is to make nzmax equal to the total number of elements in an mxArray. This approach eliminates (or, at least reduces) expensive reallocations.
See Also
| | mxSetName (Obsolete) | mxSetPi | |