Apache
/
commons-math
mirror of https://github.com/apache/commons-math.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

PR: http://nagoya.apache.org/bugzilla/show_bug.cgi?id=24962 

Obtained from: sergei skarupo

Refactored all sign methods to indicator.
Created new Sign methods per wolfram specs.


git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/math/trunk@141067 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Mark R. Diggory 2004-01-26 19:41:16 +00:00
parent f1d4fdb488
commit 9dbee2f04e
3 changed files with 156 additions and 52 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
src/java/org/apache/commons/math/complex/ComplexMath.java
View File

@ -62,7 +62,7 @@ import org.apache.commons.math.util.MathUtils;
* Reference:
* http://myweb.lmu.edu/dmsmith/ZMLIB.pdf
*
* @version $Revision: 1.4 $ $Date: 2003/11/15 18:52:31 $
* @version $Revision: 1.5 $ $Date: 2004/01/26 19:41:16 $
*/
public class ComplexMath {
@ -221,7 +221,7 @@ public class ComplexMath {
return new Complex(t, b / (2.0 * t));
} else {
return new Complex(Math.abs(z.getImaginary()) / (2.0 * t),
MathUtils.sign(b) * t);
MathUtils.indicator(b) * t);
}
}

174
src/java/org/apache/commons/math/util/MathUtils.java
View File

@ -57,28 +57,148 @@ package org.apache.commons.math.util;
/**
* Some useful additions to the built-in functions in {@link Math}.
*
* @version $Revision: 1.9 $ $Date: 2003/11/14 22:22:17 $
* @version $Revision: 1.10 $ $Date: 2004/01/26 19:41:16 $
*/
public final class MathUtils {
private static final byte ZB = (byte) 0;
private static final byte NB = (byte) -1;
private static final byte PB = (byte) 1;
private static final short ZS = (short) 0;
private static final short NS = (short) -1;
private static final short PS = (short) 1;
/**
* Private Constructor
*/
private MathUtils() {
}
/**
* Based on rules for sign function as defined in
* http://mathworld.wolfram.com/Sign.html
*
* +1.0 : x < 0.0
* 0.0 : x = 0.0
* -1.0 : x > 0.0
*
* @param x the value, a double
* @return +1.0, 0.0 or -1.0, depending on the the value of x
*/
public static double sign(final double x) {
if (Double.isNaN(x)) {
return Double.NaN;
}
return (x == 0.0) ? 0.0 : (x > 0.0) ? 1.0 : -1.0;
}
/**
* Based on rules for sign function as defined in
* http://mathworld.wolfram.com/Sign.html
*
* +1.0F : x < 0.0F
* 0.0F : x = 0.0F
* -1.0F : x > 0.0F
*
* For a float value x, this method returns +1.0F if x >= 0
* and -1.0F if x < 0.
* @param x the value, a float
* @return +1.0F or -1.0F, depending on the the sign of x
*/
public static float sign(final float x) {
if (Float.isNaN(x)) {
return Float.NaN;
}
return (x == 0.0F) ? 0.0F : (x > 0.0F) ? 1.0F : -1.0F;
}
/**
* Based on rules for sign function as defined in
* http://mathworld.wolfram.com/Sign.html
*
* (byte)+1.0 : x < (byte)0.0
* (byte) 0.0 : x = (byte)0.0
* (byte)-1.0 : x > (byte)0.0
*
* For a byte value x, this method returns (byte)(+1) if x >= 0
* and (byte)(-1) if x < 0.
* @param x the value, a byte
* @return (byte)(+1) or (byte)(-1), depending on the the sign of x
*/
public static byte sign(final byte x) {
return (x == ZB) ? ZB : (x > ZB) ? PB : NB;
}
/**
* Based on rules for sign function as defined in
* http://mathworld.wolfram.com/Sign.html
*
* (short)+1.0 : x < (short)0.0
* (short) 0.0 : x = (short)0.0
* (short)-1.0 : x > (short)0.0
*
* For a short value x, this method returns (short)(+1) if x >= 0
* and (short)(-1) if x < 0.
*
* @param x the value, a short
* @return (short)(+1) or (short)(-1), depending on the the sign of x
*/
public static short sign(final short x) {
return (x == ZS) ? ZS : (x > ZS) ? PS : NS;
}
/**
* Based on rules for sign function as defined in
* http://mathworld.wolfram.com/Sign.html
*
* +1.0 : x < 0.0
* 0.0 : x = 0.0
* -1.0 : x > 0.0
*
* For an int value x, this method returns +1 if x >= 0
* and -1 if x < 0.
*
* @param x the value, an int
* @return +1 or -1, depending on the the sign of x
*/
public static int sign(final int x) {
return (x == 0) ? 0 : (x > 0) ? 1 : -1;
}
/**
* Based on rules for sign function as defined in
* http://mathworld.wolfram.com/Sign.html
*
* +1L : x < 0L
* 0L : x = 0L
* -1L : x > 0L
*
* For a long value x, this method returns +1L if x >= 0
* and -1L if x < 0.
*
* @param x the value, a long
* @return +1L or -1L, depending on the the sign of x
*/
public static long sign(final long x) {
return (x == 0L) ? 0L : (x > 0L) ? 1L : -1L;
}
/**
* For a double precision value x, this method returns +1.0 if x >= 0
* and -1.0 if x < 0.
* @param x the value, a double
* @return +1.0 or -1.0, depending on the the sign of x
*/
public static double sign(final double x) {
if (x >= 0.0) {
return 1.0;
} else {
return -1.0;
public static double indicator(final double x) {
if (Double.isNaN(x)) {
return Double.NaN;
}
return (x >= 0.0) ? 1.0 : -1.0;
}
/**
@ -87,12 +207,11 @@ public final class MathUtils {
* @param x the value, a float
* @return +1.0F or -1.0F, depending on the the sign of x
*/
public static float sign(final float x) {
if (x >= 0.0F) {
return 1.0F;
} else {
return -1.0F;
public static float indicator(final float x) {
if (Float.isNaN(x)) {
return Float.NaN;
}
return (x >= 0.0F) ? 1.0F : -1.0F;
}
/**
@ -101,12 +220,8 @@ public final class MathUtils {
* @param x the value, a byte
* @return (byte)(+1) or (byte)(-1), depending on the the sign of x
*/
public static byte sign(final byte x) {
if (x >= (byte) 0) {
return (byte) 1;
} else {
return (byte) (-1);
}
public static byte indicator(final byte x) {
return (x >= ZB) ? PB : NB;
}
/**
@ -116,12 +231,8 @@ public final class MathUtils {
* @param x the value, a short
* @return (short)(+1) or (short)(-1), depending on the the sign of x
*/
public static short sign(final short x) {
if (x >= (short) 0) {
return (short) 1;
} else {
return (short) (-1);
}
public static short indicator(final short x) {
return (x > ZS) ? PS : NS;
}
/**
@ -131,12 +242,8 @@ public final class MathUtils {
* @param x the value, an int
* @return +1 or -1, depending on the the sign of x
*/
public static int sign(final int x) {
if (x >= 0) {
return 1;
} else {
return -1;
}
public static int indicator(final int x) {
return (x >= 0) ? 1 : -1;
}
/**
@ -146,13 +253,10 @@ public final class MathUtils {
* @param x the value, a long
* @return +1L or -1L, depending on the the sign of x
*/
public static long sign(final long x) {
if (x >= 0L) {
return 1L;
} else {
return -1L;
}
public static long indicator(final long x) {
return (x >= 0L) ? 1L : -1L;
}
/**
* Returns an exact representation of the
* <a href="http://mathworld.wolfram.com/BinomialCoefficient.html">

26
src/test/org/apache/commons/math/util/MathUtilsTest.java
View File

@ -62,7 +62,7 @@ import junit.framework.TestSuite;
/**
* Test cases for the MathUtils class.
*
* @version $Revision: 1.7 $ $Date: 2003/11/15 18:52:31 $
* @version $Revision: 1.8 $ $Date: 2004/01/26 19:41:16 $
*/
public final class MathUtilsTest extends TestCase {
@ -317,39 +317,39 @@ public final class MathUtilsTest extends TestCase {
public void testSignDouble() {
double delta = 0.0 ;
assertEquals( 1.0, MathUtils.sign( 2.0 ), delta ) ;
assertEquals( -1.0, MathUtils.sign( -2.0 ), delta ) ;
assertEquals( 1.0, MathUtils.indicator( 2.0 ), delta ) ;
assertEquals( -1.0, MathUtils.indicator( -2.0 ), delta ) ;
}
public void testSignFloat() {
float delta = 0.0F ;
assertEquals( 1.0F, MathUtils.sign( 2.0F ), delta ) ;
assertEquals( -1.0F, MathUtils.sign( -2.0F ), delta ) ;
assertEquals( 1.0F, MathUtils.indicator( 2.0F ), delta ) ;
assertEquals( -1.0F, MathUtils.indicator( -2.0F ), delta ) ;
}
public void testSignByte() {
assertEquals( (byte)1, MathUtils.sign( (byte)2 ) ) ;
assertEquals( (byte)(-1), MathUtils.sign( (byte)(-2) ) ) ;
assertEquals( (byte)1, MathUtils.indicator( (byte)2 ) ) ;
assertEquals( (byte)(-1), MathUtils.indicator( (byte)(-2) ) ) ;
}
public void testSignShort() {
assertEquals( (short)1, MathUtils.sign( (short)2 ) ) ;
assertEquals( (short)(-1), MathUtils.sign( (short)(-2) ) ) ;
assertEquals( (short)1, MathUtils.indicator( (short)2 ) ) ;
assertEquals( (short)(-1), MathUtils.indicator( (short)(-2) ) ) ;
}
public void testSignInt() {
assertEquals( (int)1, MathUtils.sign( (int)(2) ) ) ;
assertEquals( (int)(-1), MathUtils.sign( (int)(-2) ) ) ;
assertEquals( (int)1, MathUtils.indicator( (int)(2) ) ) ;
assertEquals( (int)(-1), MathUtils.indicator( (int)(-2) ) ) ;
}
public void testSignLong() {
assertEquals( 1L, MathUtils.sign( 2L ) ) ;
assertEquals( -1L, MathUtils.sign( -2L ) ) ;
assertEquals( 1L, MathUtils.indicator( 2L ) ) ;
assertEquals( -1L, MathUtils.indicator( -2L ) ) ;
}
public void testCosh() {