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DDogleg Numerics is a high performance Java library for non-linear optimization, robust model fitting, polynomial root finding, sorting, and more.
/*
* Copyright (c) 2012-2017, Peter Abeles. All Rights Reserved.
*
* This file is part of DDogleg (http://ddogleg.org).
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* 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.
*/
package org.ddogleg.solver.impl;
import org.ddogleg.solver.Polynomial;
import org.ddogleg.solver.PolynomialRoots;
import org.ejml.data.Complex_F64;
import java.util.ArrayList;
import java.util.List;
/**
* Wrapper around {@link FindRealRootsSturm} for {@link PolynomialRoots}.
*
* @author Peter Abeles
*/
public class WrapRealRootsSturm implements PolynomialRoots {
// raw algorithm for finding real roots
FindRealRootsSturm alg;
// avoid creating memory by recycling
List roots = new ArrayList();
Complex_F64[] storage;
public WrapRealRootsSturm(FindRealRootsSturm alg) {
this.alg = alg;
storage = new Complex_F64[alg.getMaxRoots()];
for( int i = 0; i < storage.length; i++ )
storage[i] = new Complex_F64();
}
@Override
public boolean process(Polynomial poly) {
try {
alg.process(poly);
} catch( RuntimeException e ) {
return false;
}
roots.clear();
double found[] = alg.getRoots();
int N = alg.getNumberOfRoots();
for( int i = 0; i < N; i++ ) {
Complex_F64 c = storage[i];
c.real = found[i];
c.imaginary = 0;
roots.add(c);
}
return true;
}
@Override
public List getRoots() {
return roots;
}
}