/*
* Copyright (c) 2008, Harald Kuhr
* 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.
* * Neither the name "TwelveMonkeys" nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* 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 OWNER 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 com.twelvemonkeys.lang;
/**
* The class MathUtil contains methods for performing basic numeric operations
* such as the elementary exponential, logarithm, square root, and
* trigonometric functions.
*
* @author <a href="mailto:harald.kuhr@gmail.com">Harald Kuhr</a>
* @author last modified by $Author: haku $
*
* @version $Id: //depot/branches/personal/haraldk/twelvemonkeys/release-2/twelvemonkeys-core/src/main/java/com/twelvemonkeys/lang/MathUtil.java#1 $
*/
public final class MathUtil {
/** */
private MathUtil() {
}
/**
* Returns the natural logarithm (base <I>e</I>) of a double value.
* Equivalent to {@code java.lang.Math.log}, just with a proper name.
*
* @param pArg a number greater than 0.0.
* @return the value ln {@code pArg}, the natural logarithm of
* {@code pArg}.
*
* @see java.lang.Math#log(double)
*/
public static double ln(final double pArg) {
return Math.log(pArg);
}
/**
* Returns the base 10 logarithm of a double value.
*
* @param pArg a number greater than 0.0.
* @return the value log {@code pArg}, the base 10 logarithm of
* {@code pArg}.
*/
public static double log(final double pArg) {
return Math.log10(pArg);
}
private final static double LN_2 = Math.log(2);
/**
* Returns the base 2 logarithm of a double value.
*
* @param pArg a number greater than 0.0.
* @return the value log<SUB>2</SUB> {@code pArg}, the base 2
* logarithm of {@code pArg}.
*/
public static double log2(final double pArg) {
return Math.log(pArg) / LN_2;
}
/**
* Returns the base <i>N</i> logarithm of a double value, for a given base
* <i>N</i>.
*
* @param pArg a number greater than 0.0.
* @param pBase a number greater than 0.0.
*
* @return the value log<SUB>pBase</SUB> {@code pArg}, the base
* {@code pBase} logarithm of {@code pArg}.
*/
public static double log(final double pArg, final double pBase) {
return Math.log(pArg) / Math.log(pBase);
}
/**
* A replacement for {@code Math.abs}, that never returns negative values.
* {@code Math.abs(long)} does this for {@code Long.MIN_VALUE}.
*
* @see Math#abs(long)
* @see Long#MIN_VALUE
*
* @param pNumber a number
* @return the absolute value of {@code pNumber}
*
* @throws ArithmeticException if {@code pNumber == Long.MIN_VALUE}
*/
public static long abs(final long pNumber) {
if (pNumber == Long.MIN_VALUE) {
throw new ArithmeticException("long overflow: 9223372036854775808");
}
return (pNumber < 0) ? -pNumber : pNumber;
}
/**
* A replacement for {@code Math.abs}, that never returns negative values.
* {@code Math.abs(int)} does this for {@code Integer.MIN_VALUE}.
*
* @see Math#abs(int)
* @see Integer#MIN_VALUE
*
* @param pNumber a number
* @return the absolute value of {@code pNumber}
*
* @throws ArithmeticException if {@code pNumber == Integer.MIN_VALUE}
*/
public static int abs(final int pNumber) {
if (pNumber == Integer.MIN_VALUE) {
throw new ArithmeticException("int overflow: 2147483648");
}
return (pNumber < 0) ? -pNumber : pNumber;
}
}