- la4j-0.2.0.zip
- la4j
- bin
- la4j-0.2.0.jar
- LICENSE
- README
- src
- main
- java
- la4j
- decomposition
- err
- factory
- inversion
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- linear
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- util
- vector
- test
- java
- la4j
- decomposition
- inversion
- linear
- matrix
- vector
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/*
* Copyright 2011, Vladimir Kostyukov
*
* This file is part of la4j project (http://la4j.googlecode.com)
*
* 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 la4j.linear;
import la4j.err.LinearSystemException;
import la4j.factory.Factory;
import la4j.matrix.Matrix;
import la4j.vector.Vector;
public class SquareRootSolver implements LinearSystemSolver {
@Override
public Vector solve(LinearSystem linearSystem, Factory factory) throws LinearSystemException {
Matrix a = linearSystem.coefficientsMatrix();
Vector b = linearSystem.rightHandVector();
if (!a.isSymmetric()) throw new LinearSystemException("matrix a is not symmetric");
Matrix s = a.blank();
Matrix d = a.blank();
Vector x = factory.createVector(linearSystem.variables());
Vector y = factory.createVector(linearSystem.variables());
Vector z = factory.createVector(linearSystem.variables());
for (int i = 0; i < a.rows(); i++) {
double dSumand = 0;
for (int l = 0; l < i; l++) {
dSumand += Math.pow(s.get(l, i), 2) * d.get(l, l);
}
d.set(i, i, Math.signum(a.get(i, i) - dSumand));
double sSummand = 0;
for (int l = 0; l < i; l++) {
sSummand += s.get(l, i) * s.get(l, i) * d.get(l, l);
}
s.set(i, i, Math.sqrt(Math.abs(a.get(i, i) - sSummand)));
if (Math.abs(s.get(i, i)) < EPS) throw new LinearSystemException("matrix s contains '0' at main diagonal");
for (int j = i + 1; j < a.columns(); j++) {
double summand = 0;
for (int l = 0; l < i; l++) {
summand += s.get(l, i) * s.get(l, i) * d.get(l, l);
}
s.set(i, j, (a.get(i, j) - summand) / (s.get(i, i) * d.get(i, i)));
}
double zSummand = 0;
for (int l = 0; l < i; l++) {
zSummand += z.get(l) * s.get(l, i);
}
z.set(i, (b.get(i) - zSummand) / s.get(i, i));
y.set(i, z.get(i) / d.get(i, i));
}
for (int i = a.rows() - 1; i >= 0; i--) {
double summand = 0;
for (int l = i + 1; l < a.columns(); l++) {
summand += x.get(l) * s.get(i, l);
}
x.set(i, (y.get(i) - summand) / s.get(i, i));
}
return x;
}
}
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I've received a Master's Degree in Computer Science at the IT Faculty of Altai State Technical University, Russia.
Currently, I am Software Engineer at Intel Corporation.