[SciPy-dev] new sparsetools + umfpack

[Robert Cimrman]

I have updated linsolve.use_solver():

    """
    Valid keyword arguments with defaults (other ignored):
      useUmfpack = True
      assumeSortedIndices = False

    The default sparse solver is umfpack when available. This can be
changed by passing useUmfpack = False, which then causes the always
present SuperLU based solver to be used.

    Umfpack requires a CSR/CSC matrix to have sorted column/row indices.
If sure that the matrix fulfills this, pass assumeSortedIndices = True
to gain some speed.
    """

It was the easiest solution to allow 1) regular users not to bother
about matrix indices 2) power users to gain speed.

The definition of use_solver is now use_solver( **kwargs ) (previous one
was too clumsy).

The same can be achieved with new umfpack.configure() function for those
using umfpack directly.

cheers,
r.