Java Double Number Almost Equal almostEqual(double a, double b)

Description

almost Equal

License

Open Source License

Declaration

public static boolean almostEqual(double a, double b) 

Method Source Code

//package com.java2s;
/**/*  w  w w .  j  av a2s  . c  o m*/
 * Copyright 2015 Palantir Technologies
 *
 * Licensed under the BSD-3 License (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://opensource.org/licenses/BSD-3-Clause
 *
 * 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.
 */

public class Main {
    private static final double ABSOLUTE_EPSILON = 1e-7;
    private static final double RELATIVE_EPSILON = 1e-10;

    public static boolean almostEqual(double a, double b) {
        if (Math.abs(a - b) <= ABSOLUTE_EPSILON)
            return true;

        double a1 = a * (1 - RELATIVE_EPSILON);
        double a2 = a * (1 + RELATIVE_EPSILON);
        if ((a1 <= b) && (b <= a2))
            return true;
        if ((a2 <= b) && (b <= a1))
            return true;

        double b1 = b * (1 - RELATIVE_EPSILON);
        double b2 = b * (1 + RELATIVE_EPSILON);
        if ((b1 <= a) && (a <= b2))
            return true;
        if ((b2 <= a) && (a <= b1))
            return true;

        return false;
    }
}

Related

1. almost(double a, double b, double prec)
2. almostEqual(double a, double b, double delta)
3. almostEqual(double[][] a, double[][] b, double delta)
4. almostEqual(final double aDouble, final double otherDouble)
5. almostEquals(double d1, double d2)