custom_pinv.py
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	# Copyright (C) 2018 by the RROMPy authors
	#
	# This file is part of RROMPy.
	#
	# RROMPy is free software: you can redistribute it and/or modify
	# it under the terms of the GNU Lesser General Public License as published by
	# the Free Software Foundation, either version 3 of the License, or
	# (at your option) any later version.
	#
	# RROMPy is distributed in the hope that it will be useful,
	# but WITHOUT ANY WARRANTY; without even the implied warranty of
	# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	# GNU Lesser General Public License for more details.
	#
	# You should have received a copy of the GNU Lesser General Public License
	# along with RROMPy. If not, see <http://www.gnu.org/licenses/>.
	#

	from copy import deepcopy as copy
	import numpy as np

	__all__ = ["customPInv"]

	def customPInv(A, rcond=-1, full=False):
	"""
	Compute the (Moore-Penrose) pseudo-inverse of a matrix.
	Calculate the generalized inverse of a matrix using its
	singular-value decomposition (SVD) and including all
	large singular values.
	"""
	A = A.conjugate()
	u, s, vt = np.linalg.svd(A, full_matrices=False)

	if rcond < 0: rcond = len(A) * np.finfo(A.dtype).eps

	cutoff = rcond * np.amax(s)
	large = s > cutoff

	sinv = copy(s)
	sinv = np.divide(1, s, where = large, out = sinv)
	sinv[~large] = 0

	res = (vt.T * sinv) @ u.T

	if full:
	return res, [np.sum(large), s, rcond]
	else:
	return res