/*
* Copyright 2009-2019 The VOTCA Development Team (http://www.votca.org)
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
#define BOOST_TEST_MAIN
#define BOOST_TEST_MODULE newton_rapson
#include <boost/test/unit_test.hpp>
#include <votca/xtp/newton_rapson.h>
using namespace votca::xtp;
using namespace votca;
BOOST_AUTO_TEST_SUITE(newton_rapson)
class Func {
public:
std::pair<double, double> operator()(double x) const {
std::pair<double, double> value;
value.first = x * x - 612;
value.second = 2 * x;
return value;
}
};
BOOST_AUTO_TEST_CASE(newton_rapson) {
Func f;
Index iterations = 50;
double tolerance = 1e-9;
NewtonRapson<Func> n(iterations, tolerance);
double root = n.FindRoot(f, 10.0);
BOOST_CHECK_EQUAL(n.getInfo(), NewtonRapson<Func>::Errors::success);
// see https://en.wikipedia.org/wiki/Newton%27s_method
BOOST_CHECK_CLOSE(root, 24.738633753, 1e-7);
}
BOOST_AUTO_TEST_SUITE_END()