# -*- coding: utf-8 -*-
# =============================================================================
# Copyright (c) 2012, Lawrence Livermore National Security, LLC.
# Produced at the Lawrence Livermore National Laboratory.
# Written by Joel Bernier <bernier2@llnl.gov> and others.
# LLNL-CODE-529294.
# All rights reserved.
#
# This file is part of HEXRD. For details on dowloading the source,
# see the file COPYING.
#
# Please also see the file LICENSE.
#
# This program 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) version 2.1 dated February 1999.
#
# This program 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 terms and conditions of the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this program (see file LICENSE); if not, write to
# the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
# Boston, MA 02111-1307 USA or visit <http://www.gnu.org/licenses/>.
# =============================================================================
import numpy as np
[docs]def newton(x0, f, fp, extra, prec=3e-16, maxiter=100):
for i in range(maxiter):
x = x0 - f(x0, *extra) / fp(x0, *extra)
relerr = np.max(np.abs(x - x0)) / np.max(np.abs(x))
if relerr < prec:
# print 'stopping at %d iters' % i
return x
x0 = x
return x0