001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 018 package org.apache.commons.math.special; 019 020 import org.apache.commons.math.MathException; 021 022 import junit.framework.TestCase; 023 024 /** 025 * @version $Revision: 670469 $ $Date: 2008-06-23 04:01:38 -0400 (Mon, 23 Jun 2008) $ 026 */ 027 public class ErfTest extends TestCase { 028 029 public void testErf0() throws MathException { 030 double actual = Erf.erf(0.0); 031 double expected = 0.0; 032 assertEquals(expected, actual, 1.0e-5); 033 } 034 035 public void testErf1960() throws MathException { 036 double x = 1.960 / Math.sqrt(2.0); 037 double actual = Erf.erf(x); 038 double expected = 0.95; 039 assertEquals(expected, actual, 1.0e-5); 040 041 actual = Erf.erf(-x); 042 expected = -expected; 043 assertEquals(expected, actual, 1.0e-5); 044 } 045 046 public void testErf2576() throws MathException { 047 double x = 2.576 / Math.sqrt(2.0); 048 double actual = Erf.erf(x); 049 double expected = 0.99; 050 assertEquals(expected, actual, 1.0e-5); 051 052 actual = Erf.erf(-x); 053 expected = -expected; 054 assertEquals(expected, actual, 1.0e-5); 055 } 056 057 public void testErf2807() throws MathException { 058 double x = 2.807 / Math.sqrt(2.0); 059 double actual = Erf.erf(x); 060 double expected = 0.995; 061 assertEquals(expected, actual, 1.0e-5); 062 063 actual = Erf.erf(-x); 064 expected = -expected; 065 assertEquals(expected, actual, 1.0e-5); 066 } 067 068 public void testErf3291() throws MathException { 069 double x = 3.291 / Math.sqrt(2.0); 070 double actual = Erf.erf(x); 071 double expected = 0.999; 072 assertEquals(expected, actual, 1.0e-5); 073 074 actual = Erf.erf(-x); 075 expected = -expected; 076 assertEquals(expected, actual, 1.0e-5); 077 } 078 }