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4477961: java.lang.Math.toDegrees(double) could be optimized
authorbpb
Mon, 22 Sep 2014 16:59:23 -0700
changeset 26727 b4e26e7f964e
parent 26726 16c5bcc0bed4
child 26728 d78714eb3f47
4477961: java.lang.Math.toDegrees(double) could be optimized Summary: Change toDegrees() and toRadians() to multiplication by a compile-time constant. Reviewed-by: mduigou, shade
jdk/src/java.base/share/classes/java/lang/Math.java file | annotate | diff | comparison | revisions
jdk/src/java.base/share/classes/java/lang/StrictMath.java file | annotate | diff | comparison | revisions 
--- a/jdk/src/java.base/share/classes/java/lang/Math.java	Thu Sep 18 11:34:14 2014 +0200
+++ b/jdk/src/java.base/share/classes/java/lang/Math.java	Mon Sep 22 16:59:23 2014 -0700
@@ -123,6 +123,18 @@
     public static final double PI = 3.14159265358979323846;
 
     /**
+     * Constant by which to multiply an angular value in degrees to obtain an
+     * angular value in radians.
+     */
+    private static final double DEGREES_TO_RADIANS = 0.017453292519943295;
+
+    /**
+     * Constant by which to multiply an angular value in radians to obtain an
+     * angular value in degrees.
+     */
+    private static final double RADIANS_TO_DEGREES = 57.29577951308232;
+
+    /**
      * Returns the trigonometric sine of an angle.  Special cases:
      * <ul><li>If the argument is NaN or an infinity, then the
      * result is NaN.
@@ -233,7 +245,7 @@
      * @since   1.2
      */
     public static double toRadians(double angdeg) {
-        return angdeg / 180.0 * PI;
+        return angdeg * DEGREES_TO_RADIANS;
     }
 
     /**
@@ -249,7 +261,7 @@
      * @since   1.2
      */
     public static double toDegrees(double angrad) {
-        return angrad * 180.0 / PI;
+        return angrad * RADIANS_TO_DEGREES;
     }
 
     /**
--- a/jdk/src/java.base/share/classes/java/lang/StrictMath.java	Thu Sep 18 11:34:14 2014 +0200
+++ b/jdk/src/java.base/share/classes/java/lang/StrictMath.java	Mon Sep 22 16:59:23 2014 -0700
@@ -98,6 +98,19 @@
     public static final double PI = 3.14159265358979323846;
 
     /**
+     * Constant by which to multiply an angular value in degrees to obtain an
+     * angular value in radians.
+     */
+    private static final double DEGREES_TO_RADIANS = 0.017453292519943295;
+
+    /**
+     * Constant by which to multiply an angular value in radians to obtain an
+     * angular value in degrees.
+     */
+
+    private static final double RADIANS_TO_DEGREES = 57.29577951308232;
+
+    /**
      * Returns the trigonometric sine of an angle. Special cases:
      * <ul><li>If the argument is NaN or an infinity, then the
      * result is NaN.
@@ -179,7 +192,7 @@
     public static strictfp double toRadians(double angdeg) {
         // Do not delegate to Math.toRadians(angdeg) because
         // this method has the strictfp modifier.
-        return angdeg / 180.0 * PI;
+        return angdeg * DEGREES_TO_RADIANS;
     }
 
     /**
@@ -196,7 +209,7 @@
     public static strictfp double toDegrees(double angrad) {
         // Do not delegate to Math.toDegrees(angrad) because
         // this method has the strictfp modifier.
-        return angrad * 180.0 / PI;
+        return angrad * RADIANS_TO_DEGREES;
     }
 
     /**
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