Author: erans
Date: Sat Aug 4 23:11:45 2012
New Revision: 1369506
URL: http://svn.apache.org/viewvc?rev=1369506&view=rev
Log:
MATH-740
Grabbing a few percents performance for "log".
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=1369506&r1=1369505&r2=1369506&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
Sat Aug 4 23:11:45 2012
@@ -1145,7 +1145,7 @@ public class FastMath {
/* Normalize the subnormal number. */
bits <<= 1;
while ( (bits & 0x0010000000000000L) == 0) {
- exp--;
+ --exp;
bits <<= 1;
}
}
@@ -1165,8 +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 */
@@ -1178,8 +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;
@@ -1199,7 +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);
@@ -1210,7 +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;
@@ -1224,14 +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 */
@@ -1243,8 +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;
