Take the square matrix A and make it symmetrical by copting elements from
    the lower half to the upper

    works IN PLACE.

    note: tries to use cython, falls back to a slower numpy version

def symmetrify(A, upper=False):
    """
    Take the square matrix A and make it symmetrical by copting elements from
    the lower half to the upper

    works IN PLACE.

    note: tries to use cython, falls back to a slower numpy version
    """
    if use_linalg_cython:
        _symmetrify_cython(A, upper)
    else:
        _symmetrify_numpy(A, upper)