
TODO: The following features are not yet supported for GraphBLAS matrices:

    linear indexing
    complex matrices
    2nd output for [x,i] = max (...) and [x,i] = min (...); needs
        modified reduction methods inside GraphBLAS
    'includenan' for min and max
    singleton expansion
    3D and higher dimensional matrices:
        this might be done by converting the higher dimensioal
        indices down to a large 2D space, ad relying on hypersparsity.
    saturating element-wise binary and unary operators for integers 

The last two features don't exist for MATLAB sparse matrices.


