"""

Aliases for functions which may be accelerated by Scipy.

Scipy_ can be built to use accelerated or otherwise improved libraries

for FFTs, linear algebra, and special functions. This module allows

developers to transparently support these accelerated functions when

scipy is available but still support users who have only installed

NumPy.

.. _Scipy : http://www.scipy.org

"""

from __future__ import division, absolute_import, print_function

# This module should be used for functions both in numpy and scipy if

#  you want to use the numpy version if available but the scipy version

#  otherwise.

#  Usage  --- from numpy.dual import fft, inv

__all__ = ['fft', 'ifft', 'fftn', 'ifftn', 'fft2', 'ifft2',

           'norm', 'inv', 'svd', 'solve', 'det', 'eig', 'eigvals',

           'eigh', 'eigvalsh', 'lstsq', 'pinv', 'cholesky', 'i0']

import numpy.linalg as linpkg

import numpy.fft as fftpkg

from numpy.lib import i0

import sys

fft = fftpkg.fft

ifft = fftpkg.ifft

fftn = fftpkg.fftn

ifftn = fftpkg.ifftn

fft2 = fftpkg.fft2

ifft2 = fftpkg.ifft2

norm = linpkg.norm

inv = linpkg.inv

svd = linpkg.svd

solve = linpkg.solve

det = linpkg.det

eig = linpkg.eig

eigvals = linpkg.eigvals

eigh = linpkg.eigh

eigvalsh = linpkg.eigvalsh

lstsq = linpkg.lstsq

pinv = linpkg.pinv

cholesky = linpkg.cholesky

_restore_dict = {}

def register_func(name, func):

    if name not in __all__:

        raise ValueError("%s not a dual function." % name)

    f = sys._getframe(0).f_globals

    _restore_dict[name] = f[name]

    f[name] = func

def restore_func(name):

    if name not in __all__:

        raise ValueError("%s not a dual function." % name)

    try:

        val = _restore_dict[name]

    except KeyError:

        return

    else:

        sys._getframe(0).f_globals[name] = val

def restore_all():

    for name in _restore_dict.keys():

        restore_func(name)