/*
* Copyright (c) 2016 Martin Davis.
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* and Eclipse Distribution License v. 1.0 which accompanies this distribution.
* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
*
* http://www.eclipse.org/org/documents/edl-v10.php.
*/
package org.locationtech.jts.math;
/**
* Various utility functions for mathematical and numerical operations.
*
* @author mbdavis
*
*/
public class MathUtil
{
/**
* Clamps a <tt>double</tt> value to a given range.
* @param x the value to clamp
* @param min the minimum value of the range
* @param max the maximum value of the range
* @return the clamped value
*/
public static double clamp(double x, double min, double max)
{
if (x < min) return min;
if (x > max) return max;
return x;
}
/**
* Clamps an <tt>int</tt> value to a given range.
* @param x the value to clamp
* @param min the minimum value of the range
* @param max the maximum value of the range
* @return the clamped value
*/
public static int clamp(int x, int min, int max)
{
if (x < min) return min;
if (x > max) return max;
return x;
}
private static final double LOG_10 = Math.log(10);
/**
* Computes the base-10 logarithm of a <tt>double</tt> value.
* <ul>
* <li>If the argument is NaN or less than zero, then the result is NaN.
* <li>If the argument is positive infinity, then the result is positive infinity.
* <li>If the argument is positive zero or negative zero, then the result is negative infinity.
* </ul>
*
* @param x a positive number
* @return the value log a, the base-10 logarithm of the input value
*/
public static double log10(double x)
{
double ln = Math.log(x);
if (Double.isInfinite(ln)) return ln;
if (Double.isNaN(ln)) return ln;
return ln / LOG_10;
}
/**
* Computes an index which wraps around a given maximum value.
* For values >= 0, this is equals to <tt>val % max</tt>.
* For values < 0, this is equal to <tt>max - (-val) % max</tt>
*
* @param index the value to wrap
* @param max the maximum value (or modulus)
* @return the wrapped index
*/
public static int wrap(int index, int max)
{
if (index < 0) {
return max - ((-index) % max);
}
return index % max;
}
/**
* Computes the average of two numbers.
*
* @param x1 a number
* @param x2 a number
* @return the average of the inputs
*/
public static double average(double x1, double x2)
{
return (x1 + x2) / 2.0;
}
public static double max(double v1, double v2, double v3)
{
double max = v1;
if (v2 > max) max = v2;
if (v3 > max) max = v3;
return max;
}
public static double max(double v1, double v2, double v3, double v4)
{
double max = v1;
if (v2 > max) max = v2;
if (v3 > max) max = v3;
if (v4 > max) max = v4;
return max;
}
public static double min(double v1, double v2, double v3, double v4)
{
double min = v1;
if (v2 < min) min = v2;
if (v3 < min) min = v3;
if (v4 < min) min = v4;
return min;
}
}