home | career | drupal | java | mac | mysql | perl | scala | uml | unix  

Java example source code file (FieldLUSolverTest.java)

This example Java source code file (FieldLUSolverTest.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

array2drowfieldmatrix, fielddecompositionsolver, fieldludecomposition, fieldlusolvertest, fieldmatrix, fieldvector, fraction, mathillegalargumentexception, singularmatrixexception, sparsefieldvector, test

The FieldLUSolverTest.java Java example source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.commons.math3.linear;

import org.apache.commons.math3.exception.MathIllegalArgumentException;
import org.apache.commons.math3.fraction.Fraction;
import org.apache.commons.math3.fraction.FractionField;
import org.junit.Assert;
import org.junit.Test;

public class FieldLUSolverTest {
    private int[][] testData = {
            { 1, 2, 3},
            { 2, 5, 3},
            { 1, 0, 8}
    };
    private int[][] luData = {
            { 2, 3, 3 },
            { 0, 5, 7 },
            { 6, 9, 8 }
    };

    // singular matrices
    private int[][] singular = {
            { 2, 3 },
            { 2, 3 }
    };
    private int[][] bigSingular = {
            { 1, 2,   3,    4 },
            { 2, 5,   3,    4 },
            { 7, 3, 256, 1930 },
            { 3, 7,   6,    8 }
    }; // 4th row = 1st + 2nd

    public static FieldMatrix<Fraction> createFractionMatrix(final int[][] data) {
        final int numRows = data.length;
        final int numCols = data[0].length;
        final Array2DRowFieldMatrix<Fraction> m;
        m = new Array2DRowFieldMatrix<Fraction>(FractionField.getInstance(),
                                                numRows, numCols);
        for (int i = 0; i < numRows; i++) {
            for (int j = 0; j < numCols; j++) {
                m.setEntry(i, j, new Fraction(data[i][j], 1));
            }
        }
        return m;
    }

    /** test singular */
    @Test
    public void testSingular() {
        FieldDecompositionSolver<Fraction> solver;
        solver = new FieldLUDecomposition<Fraction>(createFractionMatrix(testData))
            .getSolver();
        Assert.assertTrue(solver.isNonSingular());
        solver = new FieldLUDecomposition<Fraction>(createFractionMatrix(singular))
            .getSolver();
        Assert.assertFalse(solver.isNonSingular());
        solver = new FieldLUDecomposition<Fraction>(createFractionMatrix(bigSingular))
            .getSolver();
        Assert.assertFalse(solver.isNonSingular());
    }

    /** test solve dimension errors */
    @Test
    public void testSolveDimensionErrors() {
        FieldDecompositionSolver<Fraction> solver;
        solver = new FieldLUDecomposition<Fraction>(createFractionMatrix(testData))
            .getSolver();
        FieldMatrix<Fraction> b = createFractionMatrix(new int[2][2]);
        try {
            solver.solve(b);
            Assert.fail("an exception should have been thrown");
        } catch (MathIllegalArgumentException iae) {
            // expected behavior
        }
        try {
            solver.solve(b.getColumnVector(0));
            Assert.fail("an exception should have been thrown");
        } catch (MathIllegalArgumentException iae) {
            // expected behavior
        }
    }

    /** test solve singularity errors */
    @Test
    public void testSolveSingularityErrors() {
        FieldDecompositionSolver<Fraction> solver;
        solver = new FieldLUDecomposition<Fraction>(createFractionMatrix(singular))
            .getSolver();
        FieldMatrix<Fraction> b = createFractionMatrix(new int[2][2]);
        try {
            solver.solve(b);
            Assert.fail("an exception should have been thrown");
        } catch (SingularMatrixException ime) {
            // expected behavior
        }
        try {
            solver.solve(b.getColumnVector(0));
            Assert.fail("an exception should have been thrown");
        } catch (SingularMatrixException ime) {
            // expected behavior
        }
    }

    /** test solve */
    @Test
    public void testSolve() {
        FieldDecompositionSolver<Fraction> solver;
        solver = new FieldLUDecomposition<Fraction>(createFractionMatrix(testData))
            .getSolver();
        FieldMatrix<Fraction> b = createFractionMatrix(new int[][] {
                { 1, 0 }, { 2, -5 }, { 3, 1 }
        });
        FieldMatrix<Fraction> xRef = createFractionMatrix(new int[][] {
                { 19, -71 }, { -6, 22 }, { -2, 9 }
        });

        // using FieldMatrix
        FieldMatrix<Fraction> x = solver.solve(b);
        for (int i = 0; i < x.getRowDimension(); i++){
            for (int j = 0; j < x.getColumnDimension(); j++){
                Assert.assertEquals("(" + i + ", " + j + ")",
                                    xRef.getEntry(i, j), x.getEntry(i, j));
            }
        }

        // using ArrayFieldVector
        for (int j = 0; j < b.getColumnDimension(); j++) {
            final FieldVector<Fraction> xj = solver.solve(b.getColumnVector(j));
            for (int i = 0; i < xj.getDimension(); i++){
                Assert.assertEquals("(" + i + ", " + j + ")",
                                    xRef.getEntry(i, j), xj.getEntry(i));
            }
        }

        // using SparseFieldVector
        for (int j = 0; j < b.getColumnDimension(); j++) {
            final SparseFieldVector<Fraction> bj;
            bj = new SparseFieldVector<Fraction>(FractionField.getInstance(),
                                                 b.getColumn(j));
            final FieldVector<Fraction> xj = solver.solve(bj);
            for (int i = 0; i < xj.getDimension(); i++) {
                Assert.assertEquals("(" + i + ", " + j + ")",
                                    xRef.getEntry(i, j), xj.getEntry(i));
            }
        }
    }

    /** test determinant */
    @Test
    public void testDeterminant() {
        Assert.assertEquals( -1, getDeterminant(createFractionMatrix(testData)), 1E-15);
        Assert.assertEquals(-10, getDeterminant(createFractionMatrix(luData)), 1E-14);
        Assert.assertEquals(  0, getDeterminant(createFractionMatrix(singular)), 1E-15);
        Assert.assertEquals(  0, getDeterminant(createFractionMatrix(bigSingular)), 1E-15);
    }

    private double getDeterminant(final FieldMatrix<Fraction> m) {
        return new FieldLUDecomposition<Fraction>(m).getDeterminant().doubleValue();
    }
}

Other Java examples (source code examples)

Here is a short list of links related to this Java FieldLUSolverTest.java source code file:



my book on functional programming

 

new blog posts

 

Copyright 1998-2021 Alvin Alexander, alvinalexander.com
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.