You are viewing a plain text version of this content. The canonical link for it is here.
Posted to commits@commons.apache.org by lu...@apache.org on 2012/08/09 09:54:06 UTC
svn commit: r1371073 -
/commons/proper/math/trunk/src/main/java/org/apache/commons/math3/util/FastMath.java
Author: luc
Date: Thu Aug 9 07:54:06 2012
New Revision: 1371073
URL: http://svn.apache.org/viewvc?rev=1371073&view=rev
Log:
partially reverted commit 1370951 as it trashed earlier correction in FastMath
Modified:
commons/proper/math/trunk/src/main/java/org/apache/commons/math3/util/FastMath.java
Modified: commons/proper/math/trunk/src/main/java/org/apache/commons/math3/util/FastMath.java
URL: http://svn.apache.org/viewvc/commons/proper/math/trunk/src/main/java/org/apache/commons/math3/util/FastMath.java?rev=1371073&r1=1371072&r2=1371073&view=diff
==============================================================================
--- commons/proper/math/trunk/src/main/java/org/apache/commons/math3/util/FastMath.java (original)
+++ commons/proper/math/trunk/src/main/java/org/apache/commons/math3/util/FastMath.java Thu Aug 9 07:54:06 2012
@@ -18,9 +18,6 @@ package org.apache.commons.math3.util;
import java.io.PrintStream;
-import org.apache.commons.math3.exception.NotPositiveException;
-import org.apache.commons.math3.exception.util.LocalizedFormats;
-
/**
* Faster, more accurate, portable alternative to {@link Math} and
* {@link StrictMath} for large scale computation.
@@ -1148,7 +1145,7 @@ public class FastMath {
/* Normalize the subnormal number. */
bits <<= 1;
while ( (bits & 0x0010000000000000L) == 0) {
- exp--;
+ --exp;
bits <<= 1;
}
}
@@ -1168,8 +1165,9 @@ public class FastMath {
xa = aa;
xb = ab;
- double ya = LN_QUICK_COEF[LN_QUICK_COEF.length-1][0];
- double yb = LN_QUICK_COEF[LN_QUICK_COEF.length-1][1];
+ final double[] lnCoef_last = LN_QUICK_COEF[LN_QUICK_COEF.length - 1];
+ double ya = lnCoef_last[0];
+ double yb = lnCoef_last[1];
for (int i = LN_QUICK_COEF.length - 2; i >= 0; i--) {
/* Multiply a = y * x */
@@ -1181,8 +1179,9 @@ public class FastMath {
yb = aa - ya + ab;
/* Add a = y + lnQuickCoef */
- aa = ya + LN_QUICK_COEF[i][0];
- ab = yb + LN_QUICK_COEF[i][1];
+ final double[] lnCoef_i = LN_QUICK_COEF[i];
+ aa = ya + lnCoef_i[0];
+ ab = yb + lnCoef_i[1];
/* Split y = a */
tmp = aa * HEX_40000000;
ya = aa + tmp - tmp;
@@ -1202,7 +1201,7 @@ public class FastMath {
}
// lnm is a log of a number in the range of 1.0 - 2.0, so 0 <= lnm < ln(2)
- double lnm[] = lnMant.LN_MANT[(int)((bits & 0x000ffc0000000000L) >> 42)];
+ final double[] lnm = lnMant.LN_MANT[(int)((bits & 0x000ffc0000000000L) >> 42)];
/*
double epsilon = x / Double.longBitsToDouble(bits & 0xfffffc0000000000L);
@@ -1213,7 +1212,7 @@ public class FastMath {
// y is the most significant 10 bits of the mantissa
//double y = Double.longBitsToDouble(bits & 0xfffffc0000000000L);
//double epsilon = (x - y) / y;
- double epsilon = (bits & 0x3ffffffffffL) / (TWO_POWER_52 + (bits & 0x000ffc0000000000L));
+ final double epsilon = (bits & 0x3ffffffffffL) / (TWO_POWER_52 + (bits & 0x000ffc0000000000L));
double lnza = 0.0;
double lnzb = 0.0;
@@ -1227,14 +1226,15 @@ public class FastMath {
double xb = ab;
/* Need a more accurate epsilon, so adjust the division. */
- double numer = bits & 0x3ffffffffffL;
- double denom = TWO_POWER_52 + (bits & 0x000ffc0000000000L);
+ final double numer = bits & 0x3ffffffffffL;
+ final double denom = TWO_POWER_52 + (bits & 0x000ffc0000000000L);
aa = numer - xa*denom - xb * denom;
xb += aa / denom;
/* Remez polynomial evaluation */
- double ya = LN_HI_PREC_COEF[LN_HI_PREC_COEF.length-1][0];
- double yb = LN_HI_PREC_COEF[LN_HI_PREC_COEF.length-1][1];
+ final double[] lnCoef_last = LN_HI_PREC_COEF[LN_HI_PREC_COEF.length-1];
+ double ya = lnCoef_last[0];
+ double yb = lnCoef_last[1];
for (int i = LN_HI_PREC_COEF.length - 2; i >= 0; i--) {
/* Multiply a = y * x */
@@ -1246,8 +1246,9 @@ public class FastMath {
yb = aa - ya + ab;
/* Add a = y + lnHiPrecCoef */
- aa = ya + LN_HI_PREC_COEF[i][0];
- ab = yb + LN_HI_PREC_COEF[i][1];
+ final double[] lnCoef_i = LN_HI_PREC_COEF[i];
+ aa = ya + lnCoef_i[0];
+ ab = yb + lnCoef_i[1];
/* Split y = a */
tmp = aa * HEX_40000000;
ya = aa + tmp - tmp;
@@ -1581,34 +1582,6 @@ public class FastMath {
/**
- * Raise a double to an int power.
- *
- * @param d Number to raise.
- * @param e Exponent.
- * @return d<sup>e</sup>
- */
- public static double pow(double d, int e) {
- if (e == 0) {
- return 1.0;
- } else if (e < 0) {
- e = -e;
- d = 1.0 / d;
- }
-
- double result = 1;
- double d2p = d;
- while (e != 0) {
- if ((e & 0x1) != 0) {
- result *= d2p;
- }
- d2p *= d2p;
- e = e >> 1;
- }
-
- return result;
- }
-
- /**
* Computes sin(x) - x, where |x| < 1/16.
* Use a Remez polynomial approximation.
* @param x a number smaller than 1/16