wvMatrixGetDimensionality returns the number of dimensions of
matrix.
wvMatrixSize returns a pointer to the indexVector that reflects
the size of the matrix. This is a pointer to the actual index
vector element of the matrix structure, so changes to it will change the
effective size of the matrix (but not the space allocated for it).
This can be useful to reduce the size of a matrix temporarily and then
reset the size to its larger initial value. But care must be taken to
ensure that the size is never set to something larger than the size of
the matrix when it was created.
wvIsSingletonMatrix returns wvTrue if matrix is a
singleton matrix, wvFalse otherwise. A singleton matrix is a matrix
with only one element.