Set storage space for nonzero elements
#include "matrix.h" void mxSetNzmax(mxArray *pm, mwSize nzmax);
#include "fintrf.h" subroutine mxSetNzmax(pm, nzmax) mwPointer pm mwSize nzmax
pmPointer to a sparse mxArray.
nzmaxNumber of elements for mxCreateSparse to 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, then
mxSetNzmax sets the value of
nzmax to 1.
Use mxSetNzmax to assign a new value to the
nzmax field of the specified sparse mxArray.
The nzmax field holds the maximum 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. To change the size of one of these arrays:
Call mxRealloc with a pointer to the
array, setting the size to the new value of nzmax.
Call the appropriate mxSet routine
(mxSetIr, mxSetDoubles, or
mxSetComplexDoubles) to establish the new memory area
as the current one.
Ways to determine how large to make nzmax are:
Set nzmax equal to or slightly greater than the number of
nonzero elements in a sparse mxArray. This approach conserves
precious heap space.
Make nzmax equal to the total number of elements in an
mxArray. This approach eliminates (or, at least reduces)
expensive reallocations.