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Java example source code file (FastMathStrictComparisonTest.java)

This example Java source code file (FastMathStrictComparisonTest.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

class, double, exception, fastmathstrictcomparisontest, float, int_special_values, invocationtargetexception, list, method, object, only, reflection, string, stringbuilder, type, util

The FastMathStrictComparisonTest.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.util;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import org.apache.commons.math3.exception.MathArithmeticException;
import org.junit.Assert;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;
import org.junit.runners.Parameterized.Parameters;

/**
 * Test to compare FastMath results against StrictMath results for boundary values.
 * <p>
 * Running all tests independently: <br/>
 * {@code mvn test -Dtest=FastMathStrictComparisonTest}<br/>
 * or just run tests against a single method (e.g. scalb):<br/>
 * {@code mvn test -Dtest=FastMathStrictComparisonTest -DargLine="-DtestMethod=scalb"}
 */
@SuppressWarnings("boxing")
@RunWith(Parameterized.class)
public class FastMathStrictComparisonTest {

    // Values which often need special handling
    private static final Double[] DOUBLE_SPECIAL_VALUES = {
        -0.0, +0.0,                                         // 1,2
        Double.NaN,                                         // 3
        Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY, // 4,5
        -Double.MAX_VALUE, Double.MAX_VALUE,                // 6,7
        // decreasing order of absolute value to help catch first failure
        -Precision.EPSILON, Precision.EPSILON,              // 8,9
        -Precision.SAFE_MIN, Precision.SAFE_MIN,            // 10,11
        -Double.MIN_VALUE, Double.MIN_VALUE,                // 12,13
    };

    private static final Float [] FLOAT_SPECIAL_VALUES = {
        -0.0f, +0.0f,                                       // 1,2
        Float.NaN,                                          // 3
        Float.NEGATIVE_INFINITY, Float.POSITIVE_INFINITY,   // 4,5
        Float.MIN_VALUE, Float.MAX_VALUE,                   // 6,7
        -Float.MIN_VALUE, -Float.MAX_VALUE,                 // 8,9
    };

    private static final Object [] LONG_SPECIAL_VALUES = {
        -1,0,1,                                             // 1,2,3
        Long.MIN_VALUE, Long.MAX_VALUE,                     // 4,5
    };

    private static final Object[] INT_SPECIAL_VALUES = {
        -1,0,1,                                             // 1,2,3
        Integer.MIN_VALUE, Integer.MAX_VALUE,               // 4,5
    };

    private final Method mathMethod;
    private final Method fastMethod;
    private final Type[] types;
    private final Object[][] valueArrays;

    public FastMathStrictComparisonTest(Method m, Method f, Type[] types, Object[][] data) throws Exception{
        this.mathMethod=m;
        this.fastMethod=f;
        this.types=types;
        this.valueArrays=data;
    }

    @Test
    public void test1() throws Exception{
        setupMethodCall(mathMethod, fastMethod, types, valueArrays);
    }
    private static boolean isNumber(Double d) {
        return !(d.isInfinite() || d.isNaN());
    }

    private static boolean isNumber(Float f) {
        return !(f.isInfinite() || f.isNaN());
    }

    private static void reportFailedResults(Method mathMethod, Object[] params, Object expected, Object actual, int[] entries){
        final String methodName = mathMethod.getName();
        String format = null;
        long actL=0;
        long expL=0;
        if (expected instanceof Double) {
            Double exp = (Double) expected;
            Double act = (Double) actual;
            if (isNumber(exp) && isNumber(act) && exp != 0) { // show difference as hex
                actL = Double.doubleToLongBits(act);
                expL = Double.doubleToLongBits(exp);
                if (Math.abs(actL-expL)==1) {
                    // Not 100% sure off-by-one errors are allowed everywhere, so only allow for these methods
                    if (methodName.equals("toRadians") || methodName.equals("atan2")) {
                        return;
                    }
                }
                format = "%016x";
            }
        } else if (expected instanceof Float ){
            Float exp = (Float) expected;
            Float act = (Float) actual;
            if (isNumber(exp) && isNumber(act) && exp != 0) { // show difference as hex
                actL = Float.floatToIntBits(act);
                expL = Float.floatToIntBits(exp);
                format = "%08x";
            }
        }
        StringBuilder sb = new StringBuilder();
        sb.append(mathMethod.getReturnType().getSimpleName());
        sb.append(" ");
        sb.append(methodName);
        sb.append("(");
        String sep = "";
        for(Object o : params){
            sb.append(sep);
            sb.append(o);
            sep=", ";
        }
        sb.append(") expected ");
        if (format != null){
            sb.append(String.format(format, expL));
        } else {
            sb.append(expected);
        }
        sb.append(" actual ");
        if (format != null){
            sb.append(String.format(format, actL));
        } else {
            sb.append(actual);
        }
        sb.append(" entries ");
        sb.append(Arrays.toString(entries));
        String message = sb.toString();
        final boolean fatal = true;
        if (fatal) {
            Assert.fail(message);
        } else {
            System.out.println(message);
        }
    }

    private static void callMethods(Method mathMethod, Method fastMethod,
            Object[] params, int[] entries) throws IllegalAccessException {
        try {
            Object expected;
            try {
                expected = mathMethod.invoke(mathMethod, params);
            } catch (InvocationTargetException ite) {
                expected = ite.getCause();
            }
            Object actual;
            try {
                actual = fastMethod.invoke(mathMethod, params);
            } catch (InvocationTargetException ite) {
                actual = ite.getCause();
            }
            if (expected instanceof ArithmeticException) {
                Assert.assertEquals(MathArithmeticException.class, actual.getClass());
            } else  if (!expected.equals(actual)) {
                reportFailedResults(mathMethod, params, expected, actual, entries);
            }
        } catch (IllegalArgumentException e) {
            Assert.fail(mathMethod+" "+e);
        }
    }

    private static void setupMethodCall(Method mathMethod, Method fastMethod,
            Type[] types, Object[][] valueArrays) throws Exception {
        Object[] params = new Object[types.length];
        int entry1 = 0;
        int[] entries = new int[types.length];
        for(Object d : valueArrays[0]) {
            entry1++;
            params[0] = d;
            entries[0] = entry1;
            if (params.length > 1){
                int entry2 = 0;
                for(Object d1 : valueArrays[1]) {
                    entry2++;
                    params[1] = d1;
                    entries[1] = entry2;
                    callMethods(mathMethod, fastMethod, params, entries);
                }
            } else {
                callMethods(mathMethod, fastMethod, params, entries);
            }
        }
    }

    @Parameters
    public static List<Object[]> data() throws Exception {
        String singleMethod = System.getProperty("testMethod");
        List<Object[]> list = new ArrayList();
        for(Method mathMethod : StrictMath.class.getDeclaredMethods()) {
            method:
            if (Modifier.isPublic(mathMethod.getModifiers())){// Only test public methods
                Type []types = mathMethod.getGenericParameterTypes();
                if (types.length >=1) { // Only check methods with at least one parameter
                    try {
                        // Get the corresponding FastMath method
                        Method fastMethod = FastMath.class.getDeclaredMethod(mathMethod.getName(), (Class[]) types);
                        if (Modifier.isPublic(fastMethod.getModifiers())) { // It must be public too
                            if (singleMethod != null && !fastMethod.getName().equals(singleMethod)) {
                                break method;
                            }
                            Object [][] values = new Object[types.length][];
                            int index = 0;
                            for(Type t : types) {
                                if (t.equals(double.class)){
                                    values[index]=DOUBLE_SPECIAL_VALUES;
                                } else if (t.equals(float.class)) {
                                    values[index]=FLOAT_SPECIAL_VALUES;
                                } else if (t.equals(long.class)) {
                                    values[index]=LONG_SPECIAL_VALUES;
                                } else if (t.equals(int.class)) {
                                    values[index]=INT_SPECIAL_VALUES;
                                } else {
                                    System.out.println("Cannot handle class "+t+" for "+mathMethod);
                                    break method;
                                }
                                index++;
                            }
//                            System.out.println(fastMethod);
                            /*
                             * The current implementation runs each method as a separate test.
                             * Could be amended to run each value as a separate test
                             */
                            list.add(new Object[]{mathMethod, fastMethod, types, values});
//                            setupMethodCall(mathMethod, fastMethod, params, data);
                        } else {
                            System.out.println("Cannot find public FastMath method corresponding to: "+mathMethod);
                        }
                    } catch (NoSuchMethodException e) {
                        System.out.println("Cannot find FastMath method corresponding to: "+mathMethod);
                    }
                }
            }
        }
        return list;
    }
}

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