Author: erans
Date: Fri Jul 27 14:56:10 2012
New Revision: 1366400
URL: http://svn.apache.org/viewvc?rev=1366400&view=rev
Log:
MATH-762
Created an inner class to collect statements that were duplicated.
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=1366400&r1=1366399&r2=1366400&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
Fri Jul 27 14:56:10 2012
@@ -2127,9 +2127,10 @@ public class FastMath {
}
/**
- * Sine function.
- * @param x a number
- * @return sin(x)
+ * Sine function.
+ *
+ * @param x Argument.
+ * @return sin(x)
*/
public static double sin(double x) {
boolean negative = false;
@@ -2168,42 +2169,10 @@ public class FastMath {
xa = reduceResults[1];
xb = reduceResults[2];
} else if (xa > 1.5707963267948966) {
- /* Inline the Cody/Waite reduction for performance */
-
- // Estimate k
- //k = (int)(xa / 1.5707963267948966);
- int k = (int)(xa * 0.6366197723675814);
-
- // Compute remainder
- double remA;
- double remB;
- while (true) {
- double a = -k * 1.570796251296997;
- remA = xa + a;
- remB = -(remA - xa - a);
-
- a = -k * 7.549789948768648E-8;
- double b = remA;
- remA = a + b;
- remB += -(remA - b - a);
-
- a = -k * 6.123233995736766E-17;
- b = remA;
- remA = a + b;
- remB += -(remA - b - a);
-
- if (remA > 0.0) {
- break;
- }
-
- // Remainder is negative, so decrement k and try again.
- // This should only happen if the input is very close
- // to an even multiple of pi/2
- k--;
- }
- quadrant = k & 3;
- xa = remA;
- xb = remB;
+ final CodyWaite cw = new CodyWaite(xa, xb);
+ quadrant = cw.getK() & 3;
+ xa = cw.getRemA();
+ xb = cw.getRemB();
}
if (negative) {
@@ -2225,9 +2194,10 @@ public class FastMath {
}
/**
- * Cosine function
- * @param x a number
- * @return cos(x)
+ * Cosine function.
+ *
+ * @param x Argument.
+ * @return cos(x)
*/
public static double cos(double x) {
int quadrant = 0;
@@ -2254,42 +2224,10 @@ public class FastMath {
xa = reduceResults[1];
xb = reduceResults[2];
} else if (xa > 1.5707963267948966) {
- /* Inline the Cody/Waite reduction for performance */
-
- // Estimate k
- //k = (int)(xa / 1.5707963267948966);
- int k = (int)(xa * 0.6366197723675814);
-
- // Compute remainder
- double remA;
- double remB;
- while (true) {
- double a = -k * 1.570796251296997;
- remA = xa + a;
- remB = -(remA - xa - a);
-
- a = -k * 7.549789948768648E-8;
- double b = remA;
- remA = a + b;
- remB += -(remA - b - a);
-
- a = -k * 6.123233995736766E-17;
- b = remA;
- remA = a + b;
- remB += -(remA - b - a);
-
- if (remA > 0.0) {
- break;
- }
-
- // Remainder is negative, so decrement k and try again.
- // This should only happen if the input is very close
- // to an even multiple of pi/2
- k--;
- }
- quadrant = k & 3;
- xa = remA;
- xb = remB;
+ final CodyWaite cw = new CodyWaite(xa, xb);
+ quadrant = cw.getK() & 3;
+ xa = cw.getRemA();
+ xb = cw.getRemB();
}
//if (negative)
@@ -2310,9 +2248,10 @@ public class FastMath {
}
/**
- * Tangent function
- * @param x a number
- * @return tan(x)
+ * Tangent function.
+ *
+ * @param x Argument.
+ * @return tan(x)
*/
public static double tan(double x) {
boolean negative = false;
@@ -2350,46 +2289,14 @@ public class FastMath {
xa = reduceResults[1];
xb = reduceResults[2];
} else if (xa > 1.5707963267948966) {
- /* Inline the Cody/Waite reduction for performance */
-
- // Estimate k
- //k = (int)(xa / 1.5707963267948966);
- int k = (int)(xa * 0.6366197723675814);
-
- // Compute remainder
- double remA;
- double remB;
- while (true) {
- double a = -k * 1.570796251296997;
- remA = xa + a;
- remB = -(remA - xa - a);
-
- a = -k * 7.549789948768648E-8;
- double b = remA;
- remA = a + b;
- remB += -(remA - b - a);
-
- a = -k * 6.123233995736766E-17;
- b = remA;
- remA = a + b;
- remB += -(remA - b - a);
-
- if (remA > 0.0) {
- break;
- }
-
- // Remainder is negative, so decrement k and try again.
- // This should only happen if the input is very close
- // to an even multiple of pi/2
- k--;
- }
- quadrant = k & 3;
- xa = remA;
- xb = remB;
+ final CodyWaite cw = new CodyWaite(xa, xb);
+ quadrant = cw.getK() & 3;
+ xa = cw.getRemA();
+ xb = cw.getRemB();
}
if (xa > 1.5) {
- // Accurracy suffers between 1.5 and PI/2
+ // Accuracy suffers between 1.5 and PI/2
final double pi2a = 1.5707963267948966;
final double pi2b = 6.123233995736766E-17;
@@ -3795,4 +3702,76 @@ public class FastMath {
}
}
}
+
+ /** Enclose the Cody/Waite reduction (used in "sin", "cos" and "tan"). */
+ private static class CodyWaite {
+ /** k */
+ private final int finalK;
+ /** remA */
+ private final double finalRemA;
+ /** remB */
+ private final double finalRemB;
+
+ /**
+ * @param xa Argument.
+ * @param xb Argument.
+ */
+ CodyWaite(double xa,
+ double xb) {
+ // Estimate k.
+ //k = (int)(xa / 1.5707963267948966);
+ int k = (int)(xa * 0.6366197723675814);
+
+ // Compute remainder.
+ double remA;
+ double remB;
+ while (true) {
+ double a = -k * 1.570796251296997;
+ remA = xa + a;
+ remB = -(remA - xa - a);
+
+ a = -k * 7.549789948768648E-8;
+ double b = remA;
+ remA = a + b;
+ remB += -(remA - b - a);
+
+ a = -k * 6.123233995736766E-17;
+ b = remA;
+ remA = a + b;
+ remB += -(remA - b - a);
+
+ if (remA > 0) {
+ break;
+ }
+
+ // Remainder is negative, so decrement k and try again.
+ // This should only happen if the input is very close
+ // to an even multiple of pi/2.
+ --k;
+ }
+
+ this.finalK = k;
+ this.finalRemA = remA;
+ this.finalRemB = remB;
+ }
+
+ /**
+ * @return k
+ */
+ int getK() {
+ return finalK;
+ }
+ /**
+ * @return remA
+ */
+ double getRemA() {
+ return finalRemA;
+ }
+ /**
+ * @return remB
+ */
+ double getRemB() {
+ return finalRemB;
+ }
+ }
}
