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/**
* Copyright (C) 2019 Adrien Hopkins
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
package org.unitConverter.math;
/**
* A class that contains methods to compare float and double values.
*
* @author Adrien Hopkins
* @since 2019-03-18
* @since v0.2.0
*/
public final class DecimalComparison {
/**
* The value used for double comparison. If two double values are within this value multiplied by the larger value,
* they are considered equal.
*
* @since 2019-03-18
* @since v0.2.0
*/
public static final double DOUBLE_EPSILON = 1.0e-15;
/**
* The value used for float comparison. If two float values are within this value multiplied by the larger value,
* they are considered equal.
*
* @since 2019-03-18
* @since v0.2.0
*/
public static final float FLOAT_EPSILON = 1.0e-6f;
/**
* Tests for equality of double values using {@link #DOUBLE_EPSILON}.
*
* @param a
* first value to test
* @param b
* second value to test
* @return whether they are equal
* @since 2019-03-18
* @since v0.2.0
*/
public static final boolean equals(final double a, final double b) {
return DecimalComparison.equals(a, b, DOUBLE_EPSILON);
}
/**
* Tests for double equality using a custom epsilon value.
*
* @param a
* first value to test
* @param b
* second value to test
* @param epsilon
* allowed difference
* @return whether they are equal
* @since 2019-03-18
* @since v0.2.0
*/
public static final boolean equals(final double a, final double b, final double epsilon) {
return Math.abs(a - b) <= epsilon * Math.max(Math.abs(a), Math.abs(b));
}
/**
* Tests for equality of float values using {@link #FLOAT_EPSILON}.
*
* @param a
* first value to test
* @param b
* second value to test
* @return whether they are equal
* @since 2019-03-18
* @since v0.2.0
*/
public static final boolean equals(final float a, final float b) {
return DecimalComparison.equals(a, b, FLOAT_EPSILON);
}
/**
* Tests for float equality using a custom epsilon value.
*
* @param a
* first value to test
* @param b
* second value to test
* @param epsilon
* allowed difference
* @return whether they are equal
* @since 2019-03-18
* @since v0.2.0
*/
public static final boolean equals(final float a, final float b, final float epsilon) {
return Math.abs(a - b) <= epsilon * Math.max(Math.abs(a), Math.abs(b));
}
// You may NOT get any DecimalComparison instances
private DecimalComparison() {
throw new AssertionError();
}
}
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