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Commons Math example source code file (PolynomialFunctionTest.java)

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

Java - Commons Math tags/keywords

mathexception, mathexception, polynomialfunction, polynomialfunction, polynomialfunctiontest, polynomialfunctiontest, string, string, testcase

The Commons Math PolynomialFunctionTest.java 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.math.analysis.polynomials;

// commons-math
import org.apache.commons.math.MathException;
import org.apache.commons.math.TestUtils;
// junit
import junit.framework.TestCase;

/**
 * Tests the PolynomialFunction implementation of a UnivariateRealFunction.
 *
 * @version $Revision: 917261 $
 * @author Matt Cliff <matt@mattcliff.com>
 */
public final class PolynomialFunctionTest extends TestCase {

    /** Error tolerance for tests */
    protected double tolerance = 1.0e-12;

    /**
     * tests the value of a constant polynomial.
     *
     * <p>value of this is 2.5 everywhere.

*/ public void testConstants() throws MathException { double[] c = { 2.5 }; PolynomialFunction f = new PolynomialFunction( c ); // verify that we are equal to c[0] at several (nonsymmetric) places assertEquals( f.value( 0.0), c[0], tolerance ); assertEquals( f.value( -1.0), c[0], tolerance ); assertEquals( f.value( -123.5), c[0], tolerance ); assertEquals( f.value( 3.0), c[0], tolerance ); assertEquals( f.value( 456.89), c[0], tolerance ); assertEquals(f.degree(), 0); assertEquals(f.derivative().value(0), 0, tolerance); assertEquals(f.polynomialDerivative().derivative().value(0), 0, tolerance); } /** * tests the value of a linear polynomial. * * <p>This will test the function f(x) = 3*x - 1.5

* <p>This will have the values * <tt>f(0.0) = -1.5, f(-1.0) = -4.5, f(-2.5) = -9.0, * f(0.5) = 0.0, f(1.5) = 3.0</tt> and f(3.0) = 7.5 * </p> */ public void testLinear() throws MathException { double[] c = { -1.5, 3.0 }; PolynomialFunction f = new PolynomialFunction( c ); // verify that we are equal to c[0] when x=0 assertEquals( f.value( 0.0), c[0], tolerance ); // now check a few other places assertEquals( -4.5, f.value( -1.0), tolerance ); assertEquals( -9.0, f.value( -2.5), tolerance ); assertEquals( 0.0, f.value( 0.5), tolerance ); assertEquals( 3.0, f.value( 1.5), tolerance ); assertEquals( 7.5, f.value( 3.0), tolerance ); assertEquals(f.degree(), 1); assertEquals(f.polynomialDerivative().derivative().value(0), 0, tolerance); } /** * Tests a second order polynomial. * <p> This will test the function f(x) = 2x^2 - 3x -2 = (2x+1)(x-2)

* */ public void testQuadratic() { double[] c = { -2.0, -3.0, 2.0 }; PolynomialFunction f = new PolynomialFunction( c ); // verify that we are equal to c[0] when x=0 assertEquals( f.value( 0.0), c[0], tolerance ); // now check a few other places assertEquals( 0.0, f.value( -0.5), tolerance ); assertEquals( 0.0, f.value( 2.0), tolerance ); assertEquals( -2.0, f.value( 1.5), tolerance ); assertEquals( 7.0, f.value( -1.5), tolerance ); assertEquals( 265.5312, f.value( 12.34), tolerance ); } /** * This will test the quintic function * f(x) = x^2(x-5)(x+3)(x-1) = x^5 - 3x^4 -13x^3 + 15x^2</p> * */ public void testQuintic() { double[] c = { 0.0, 0.0, 15.0, -13.0, -3.0, 1.0 }; PolynomialFunction f = new PolynomialFunction( c ); // verify that we are equal to c[0] when x=0 assertEquals( f.value( 0.0), c[0], tolerance ); // now check a few other places assertEquals( 0.0, f.value( 5.0), tolerance ); assertEquals( 0.0, f.value( 1.0), tolerance ); assertEquals( 0.0, f.value( -3.0), tolerance ); assertEquals( 54.84375, f.value( -1.5), tolerance ); assertEquals( -8.06637, f.value( 1.3), tolerance ); assertEquals(f.degree(), 5); } /** * tests the firstDerivative function by comparison * * <p>This will test the functions * <tt>f(x) = x^3 - 2x^2 + 6x + 3, g(x) = 3x^2 - 4x + 6 * and <tt>h(x) = 6x - 4 */ public void testfirstDerivativeComparison() throws MathException { double[] f_coeff = { 3.0, 6.0, -2.0, 1.0 }; double[] g_coeff = { 6.0, -4.0, 3.0 }; double[] h_coeff = { -4.0, 6.0 }; PolynomialFunction f = new PolynomialFunction( f_coeff ); PolynomialFunction g = new PolynomialFunction( g_coeff ); PolynomialFunction h = new PolynomialFunction( h_coeff ); // compare f' = g assertEquals( f.derivative().value(0.0), g.value(0.0), tolerance ); assertEquals( f.derivative().value(1.0), g.value(1.0), tolerance ); assertEquals( f.derivative().value(100.0), g.value(100.0), tolerance ); assertEquals( f.derivative().value(4.1), g.value(4.1), tolerance ); assertEquals( f.derivative().value(-3.25), g.value(-3.25), tolerance ); // compare g' = h assertEquals( g.derivative().value(Math.PI), h.value(Math.PI), tolerance ); assertEquals( g.derivative().value(Math.E), h.value(Math.E), tolerance ); } public void testString() { PolynomialFunction p = new PolynomialFunction(new double[] { -5.0, 3.0, 1.0 }); checkPolynomial(p, "-5.0 + 3.0 x + x^2"); checkPolynomial(new PolynomialFunction(new double[] { 0.0, -2.0, 3.0 }), "-2.0 x + 3.0 x^2"); checkPolynomial(new PolynomialFunction(new double[] { 1.0, -2.0, 3.0 }), "1.0 - 2.0 x + 3.0 x^2"); checkPolynomial(new PolynomialFunction(new double[] { 0.0, 2.0, 3.0 }), "2.0 x + 3.0 x^2"); checkPolynomial(new PolynomialFunction(new double[] { 1.0, 2.0, 3.0 }), "1.0 + 2.0 x + 3.0 x^2"); checkPolynomial(new PolynomialFunction(new double[] { 1.0, 0.0, 3.0 }), "1.0 + 3.0 x^2"); checkPolynomial(new PolynomialFunction(new double[] { 0.0 }), "0"); } public void testAddition() { PolynomialFunction p1 = new PolynomialFunction(new double[] { -2.0, 1.0 }); PolynomialFunction p2 = new PolynomialFunction(new double[] { 2.0, -1.0, 0.0 }); checkNullPolynomial(p1.add(p2)); p2 = p1.add(p1); checkPolynomial(p2, "-4.0 + 2.0 x"); p1 = new PolynomialFunction(new double[] { 1.0, -4.0, 2.0 }); p2 = new PolynomialFunction(new double[] { -1.0, 3.0, -2.0 }); p1 = p1.add(p2); assertEquals(1, p1.degree()); checkPolynomial(p1, "-x"); } public void testSubtraction() { PolynomialFunction p1 = new PolynomialFunction(new double[] { -2.0, 1.0 }); checkNullPolynomial(p1.subtract(p1)); PolynomialFunction p2 = new PolynomialFunction(new double[] { -2.0, 6.0 }); p2 = p2.subtract(p1); checkPolynomial(p2, "5.0 x"); p1 = new PolynomialFunction(new double[] { 1.0, -4.0, 2.0 }); p2 = new PolynomialFunction(new double[] { -1.0, 3.0, 2.0 }); p1 = p1.subtract(p2); assertEquals(1, p1.degree()); checkPolynomial(p1, "2.0 - 7.0 x"); } public void testMultiplication() { PolynomialFunction p1 = new PolynomialFunction(new double[] { -3.0, 2.0 }); PolynomialFunction p2 = new PolynomialFunction(new double[] { 3.0, 2.0, 1.0 }); checkPolynomial(p1.multiply(p2), "-9.0 + x^2 + 2.0 x^3"); p1 = new PolynomialFunction(new double[] { 0.0, 1.0 }); p2 = p1; for (int i = 2; i < 10; ++i) { p2 = p2.multiply(p1); checkPolynomial(p2, "x^" + i); } } public void testSerial() { PolynomialFunction p2 = new PolynomialFunction(new double[] { 3.0, 2.0, 1.0 }); assertEquals(p2, TestUtils.serializeAndRecover(p2)); } /** * tests the firstDerivative function by comparison * * <p>This will test the functions * <tt>f(x) = x^3 - 2x^2 + 6x + 3, g(x) = 3x^2 - 4x + 6 * and <tt>h(x) = 6x - 4 */ public void testMath341() throws MathException { double[] f_coeff = { 3.0, 6.0, -2.0, 1.0 }; double[] g_coeff = { 6.0, -4.0, 3.0 }; double[] h_coeff = { -4.0, 6.0 }; PolynomialFunction f = new PolynomialFunction( f_coeff ); PolynomialFunction g = new PolynomialFunction( g_coeff ); PolynomialFunction h = new PolynomialFunction( h_coeff ); // compare f' = g assertEquals( f.derivative().value(0.0), g.value(0.0), tolerance ); assertEquals( f.derivative().value(1.0), g.value(1.0), tolerance ); assertEquals( f.derivative().value(100.0), g.value(100.0), tolerance ); assertEquals( f.derivative().value(4.1), g.value(4.1), tolerance ); assertEquals( f.derivative().value(-3.25), g.value(-3.25), tolerance ); // compare g' = h assertEquals( g.derivative().value(Math.PI), h.value(Math.PI), tolerance ); assertEquals( g.derivative().value(Math.E), h.value(Math.E), tolerance ); } public void checkPolynomial(PolynomialFunction p, String reference) { assertEquals(reference, p.toString()); } private void checkNullPolynomial(PolynomialFunction p) { for (double coefficient : p.getCoefficients()) { assertEquals(0.0, coefficient, 1.0e-15); } } }

Other Commons Math examples (source code examples)

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