org.jaitools.numeric.CompareOp Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of jt-all Show documentation
Show all versions of jt-all Show documentation
Provides a single jar containing all JAITools modules which you can
use instead of including individual modules in your project. Note:
It does not include the Jiffle scripting language or Jiffle image
operator.
/*
* Copyright (c) 2011, Michael Bedward. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright notice, this
* list of conditions and the following disclaimer in the documentation and/or
* other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.jaitools.numeric;
/**
* Provides static methods to compare floating point values, taking into account
* an absolute or proportional tolerance. There are methods for both {@code float} and
* {@code double} values.
* The {@code acompare} and {@code aequal} methods use absolute tolerance while
* the {@code pcompare} and {@code pequal} methods use proportional tolerance.
*
* For the proportional tolerance methods, a corresponding absolute tolerance
* is calculated as:
*
* atol = |ptol| * MAX(|x1|,|x2|)
*
* Note: this class does not give any special consideration to the Float
* and Double constants {@code NEGATIVE_INFINITY}, {@code POSITIVE_INFINITY}
* and {@code NaN} over that provided by Java itself.
*
* @author Michael Bedward
* @since 1.1
* @version $Id$
*/
public class CompareOp {
/** Default tolerance for double comparisons: 1.0e-8 */
public static final double DTOL = 1.0e-8d;
/** Default tolerance for float comparisons: 1.0e-4 */
public static final float FTOL = 1.0e-4f;
/**
* Tests if the given {@code double} value is within the default tolerance
* of zero.
*
* @param x the value
* @return {@code true} if zero; {@code false} otherwise
*/
public static boolean isZero(double x) {
return Math.abs(x) < DTOL;
}
/**
* Tests if the given {@code float} value is within the default tolerance
* of zero.
*
* @param x the value
* @return {@code true} if zero; {@code false} otherwise
*/
public static boolean isZero(float x) {
return Math.abs(x) < FTOL;
}
/**
* Tests if the given {@code double} value is within the specified tolerance
* of zero. Note that performance reasons, {@code tol} is assumed
* to be positive, ie. this is not checked.
*
* @param x the value
* @param tol the tolerance
* @return {@code true} if zero; {@code false} otherwise
*/
public static boolean isZero(double x, double tol) {
return Math.abs(x) < tol;
}
/**
* Tests if the given {@code float} value is within the specified tolerance
* of zero. Note that performance reasons, {@code tol} is assumed
* to be positive, ie. this is not checked.
*
* @param x the value
* @param tol the tolerance
* @return {@code true} if zero; {@code false} otherwise
*/
public static boolean isZero(float x, float tol) {
return Math.abs(x) < tol;
}
/**
* Compares two {@code double} values using the default tolerance.
*
* @param x1 first value
* @param x2 second value
*
* @return a value less than 0 if x1 is less than x2; 0 if x1 is equal to x2;
* a value greater than 0 if x1 is greater than x2
*/
public static int acompare(double x1, double x2) {
if (isZero(x1 - x2)) {
return 0;
} else {
return Double.compare(x1, x2);
}
}
/**
* Compares two {@code float} values using the default tolerance.
*
* @param x1 first value
* @param x2 second value
*
* @return a value less than 0 if x1 is less than x2; 0 if x1 is equal to x2;
* a value greater than 0 if x1 is greater than x2
*/
public static int acompare(float x1, float x2) {
if (isZero(x1 - x2)) {
return 0;
} else {
return Float.compare(x1, x2);
}
}
/**
* Compares two {@code double} values using the specified tolerance.
* Note that performance reasons, {@code tol} is assumed
* to be positive, ie. this is not checked.
*
* @param x1 first value
* @param x2 second value
* @param tol comparison tolerance
*
* @return a value less than 0 if x1 is less than x2; 0 if x1 is equal to x2;
* a value greater than 0 if x1 is greater than x2
*/
public static int acompare(double x1, double x2, double tol) {
if (isZero(x1 - x2, tol)) {
return 0;
} else {
return Double.compare(x1, x2);
}
}
/**
* Compares two {@code float} values using the specified tolerance.
* Note that performance reasons, {@code tol} is assumed
* to be positive, ie. this is not checked.
*
* @param x1 first value
* @param x2 second value
* @param tol comparison tolerance
*
* @return a value less than 0 if x1 is less than x2; 0 if x1 is equal to x2;
* a value greater than 0 if x1 is greater than x2
*/
public static int acompare(float x1, float x2, float tol) {
if (isZero(x1 - x2, tol)) {
return 0;
} else {
return Float.compare(x1, x2);
}
}
/**
* Compares two {@code double} values using the specified proportional
* tolerance. This is equivalent to:
*
* double absoluteTol = Math.abs(propTol) * Math.max(Math.abs(x1), Math.abs(x2));
* int comp = acompare(x1, x2, absTol);
*
*
* @param x1 first value
* @param x2 second value
* @param propTol proportional tolerance between 0 and 1
*
* @return a value less than 0 if x1 is less than x2; 0 if x1 is equal to x2;
* a value greater than 0 if x1 is greater than x2
*/
public static int pcompare(double x1, double x2, double propTol) {
if (aequal(x1, x2)) {
return 0;
}
int comp = acompare(Math.abs(x1), Math.abs(x2));
double absTol = Math.abs(propTol) * (comp > 0 ? x1 : x2);
return acompare(x1, x2, absTol);
}
/**
* Compares two {@code float} values using the specified proportional
* tolerance. This is equivalent to:
*
* float absoluteTol = Math.abs(propTol) * Math.max(Math.abs(x1), Math.abs(x2));
* int comp = acompare(x1, x2, absTol);
*
*
* @param x1 first value
* @param x2 second value
* @param propTol proportional tolerance between 0 and 1
*
* @return a value less than 0 if x1 is less than x2; 0 if x1 is equal to x2;
* a value greater than 0 if x1 is greater than x2
*/
public static int pcompare(float x1, float x2, float propTol) {
if (aequal(x1, x2)) {
return 0;
}
int comp = acompare(Math.abs(x1), Math.abs(x2));
double absTol = Math.abs(propTol) * (comp > 0 ? x1 : x2);
return acompare(x1, x2, absTol);
}
/**
* Tests if two {@code double} values are equal within the default tolerance.
* This is equivalent to {@code dzero(x1 - x2)}.
*
* @param x1 first value
* @param x2 second value
*
* @return {@code true} if equal; {@code false} otherwise
*/
public static boolean aequal(double x1, double x2) {
return isZero(x1 - x2);
}
/**
* Tests if two {@code float} values are equal within the default tolerance.
* This is equivalent to {@code dzero(x1 - x2)}.
*
* @param x1 first value
* @param x2 second value
*
* @return {@code true} if equal; {@code false} otherwise
*/
public static boolean aequal(float x1, float x2) {
return isZero(x1 - x2);
}
/**
* Tests if two {@code double} values are equal within the specified tolerance.
* This is equivalent to {@code dzero(x1 - x2, tol)}.
* Note that performance reasons, {@code tol} is assumed
* to be positive, ie. this is not checked.
*
* @param x1 first value
* @param x2 second value
* @param tol comparison tolerance
*
* @return {@code true} if equal; {@code false} otherwise
*/
public static boolean aequal(double x1, double x2, double tol) {
return isZero(x1 - x2, tol);
}
/**
* Tests if two {@code float} values are equal within the specified tolerance.
* This is equivalent to {@code dzero(x1 - x2, tol)}.
* Note that performance reasons, {@code tol} is assumed
* to be positive, ie. this is not checked.
*
* @param x1 first value
* @param x2 second value
* @param tol comparison tolerance
*
* @return {@code true} if equal; {@code false} otherwise
*/
public static boolean aequal(float x1, float x2, float tol) {
return isZero(x1 - x2, tol);
}
/**
* Tests if two {@code double} values are equal within the specified
* proportional tolerance. This is equivalent to:
*
* double absoluteTol = Math.abs(propTol) * Math.max(Math.abs(x1), Math.abs(x2));
* boolean b = aequal(x1, x2, absTol);
*
*
* @param x1 first value
* @param x2 second value
* @param propTol proportional tolerance between 0 and 1
*
* @return {@code true} if equal; {@code false} otherwise
*/
public static boolean pequal(double x1, double x2, double propTol) {
if (aequal(x1, x2)) {
return true;
}
int comp = acompare(Math.abs(x1), Math.abs(x2));
double absTol = Math.abs(propTol) * (comp > 0 ? x1 : x2);
return aequal(x1, x2, absTol);
}
/**
* Tests if two {@code float} values are equal within the specified
* proportional tolerance. This is equivalent to:
*
* float absoluteTol = Math.abs(propTol) * Math.max(Math.abs(x1), Math.abs(x2));
* boolean b = aequal(x1, x2, absTol);
*
*
* @param x1 first value
* @param x2 second value
* @param propTol proportional tolerance between 0 and 1
*
* @return {@code true} if equal; {@code false} otherwise
*/
public static boolean pequal(float x1, float x2, float propTol) {
if (aequal(x1, x2)) {
return true;
}
int comp = acompare(Math.abs(x1), Math.abs(x2));
double absTol = Math.abs(propTol) * (comp > 0 ? x1 : x2);
return aequal(x1, x2, absTol);
}
}