MATH-689

Implemented "copySign" for integral types. Removed redundant "indicator"
functions.
Moved "indicator" tests (for floating point arguments) to "FastMathTest",
as the corresponding "copySign" methods are in "FastMath".


git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1206274 13f79535-47bb-0310-9956-ffa450edef68

src/main/java/org/apache/commons/math/complex/Complex.java

@@ -921,7 +921,7 @@ public class Complex implements FieldElement<Complex>, Serializable  {
      * where <ul>
      * <li>{@code |a| = }{@link Math#abs}(a)</li>
      * <li>{@code |a + bi| = }{@link Complex#abs}(a + bi)</li>
-     * <li>{@code sign(b) =  }{@link MathUtils#indicator}(b)
+     * <li>{@code sign(b) =  }{@link FastMath#copySign(double,double) copySign(1d, b)}
      * </ul>
      * <br/>
      * Returns {@link Complex#NaN} if either real or imaginary part of the
@@ -957,7 +957,7 @@ public class Complex implements FieldElement<Complex>, Serializable  {
             return createComplex(t, imaginary / (2.0 * t));
         } else {
             return createComplex(FastMath.abs(imaginary) / (2.0 * t),
-                                 MathUtils.indicator(imaginary) * t);
+                                 FastMath.copySign(1d, imaginary) * t);
         }
     }
 

src/main/java/org/apache/commons/math/util/MathUtils.java

@@ -82,77 +82,6 @@ public final class MathUtils {
         return Arrays.hashCode(value);
     }
 
-    /**
-     * 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 sign of x
-     */
-    public static byte indicator(final byte x) {
-        return (x >= ZB) ? PB : NB;
-    }
-
-    /**
-     * For a double precision value x, this method returns +1.0 if x >= 0 and
-     * -1.0 if x < 0. Returns {@code NaN} if {@code x} is
-     * {@code NaN}.
-     *
-     * @param x the value, a double
-     * @return +1.0 or -1.0, depending on the sign of x
-     */
-    public static double indicator(final double x) {
-        if (Double.isNaN(x)) {
-            return Double.NaN;
-        }
-        return (x >= 0.0) ? 1.0 : -1.0;
-    }
-
-    /**
-     * For a float value x, this method returns +1.0F if x >= 0 and -1.0F if x <
-     * 0. Returns {@code NaN} if {@code x} is {@code NaN}.
-     *
-     * @param x the value, a float
-     * @return +1.0F or -1.0F, depending on the sign of x
-     */
-    public static float indicator(final float x) {
-        if (Float.isNaN(x)) {
-            return Float.NaN;
-        }
-        return (x >= 0.0F) ? 1.0F : -1.0F;
-    }
-
-    /**
-     * 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 sign of x
-     */
-    public static int indicator(final int x) {
-        return (x >= 0) ? 1 : -1;
-    }
-
-    /**
-     * 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 sign of x
-     */
-    public static long indicator(final long x) {
-        return (x >= 0L) ? 1L : -1L;
-    }
-
-    /**
-     * 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 sign of x
-     */
-    public static short indicator(final short x) {
-        return (x >= ZS) ? PS : NS;
-    }
-
     /**
      * Normalize an angle in a 2&pi wide interval around a center value.
      * <p>This method has three main uses:</p>
@@ -235,6 +164,72 @@ public final class MathUtils {
         }
     }
 
+    /**
+     * Returns the first argument with the sign of the second argument.
+     *
+     * @param magnitude Magnitude of the returned value.
+     * @param sign Sign of the returned value.
+     * @return a value with magnitude equal to {@code magnitude} and with the
+     * same sign as the {@code sign} argument.
+     * @throws MathArithmeticException if {@code magnitude == Short.MIN_VALUE}
+     * and {@code sign >= 0}.
+     */
+    public static short copySign(short magnitude, short sign) {
+        if ((magnitude >= 0 && sign >= 0) ||
+            (magnitude < 0 && sign < 0)) { // Sign is OK.
+            return magnitude;
+        } else if (sign >= 0 &&
+                   magnitude == Short.MIN_VALUE) {
+            throw new MathArithmeticException(LocalizedFormats.OVERFLOW);
+        } else {
+            return (short) -magnitude; // Flip sign.
+        }
+    }
+
+    /**
+     * Returns the first argument with the sign of the second argument.
+     *
+     * @param magnitude Magnitude of the returned value.
+     * @param sign Sign of the returned value.
+     * @return a value with magnitude equal to {@code magnitude} and with the
+     * same sign as the {@code sign} argument.
+     * @throws MathArithmeticException if {@code magnitude == Integer.MIN_VALUE}
+     * and {@code sign >= 0}.
+     */
+    public static int copySign(int magnitude, int sign) {
+        if ((magnitude >= 0 && sign >= 0) ||
+            (magnitude < 0 && sign < 0)) { // Sign is OK.
+            return magnitude;
+        } else if (sign >= 0 &&
+                   magnitude == Integer.MIN_VALUE) {
+            throw new MathArithmeticException(LocalizedFormats.OVERFLOW);
+        } else {
+            return (int) -magnitude; // Flip sign.
+        }
+    }
+
+    /**
+     * Returns the first argument with the sign of the second argument.
+     *
+     * @param magnitude Magnitude of the returned value.
+     * @param sign Sign of the returned value.
+     * @return a value with magnitude equal to {@code magnitude} and with the
+     * same sign as the {@code sign} argument.
+     * @throws MathArithmeticException if {@code magnitude == Long.MIN_VALUE}
+     * and {@code sign >= 0}.
+     */
+    public static long copySign(long magnitude, long sign) {
+        if ((magnitude >= 0 && sign >= 0) ||
+            (magnitude < 0 && sign < 0)) { // Sign is OK.
+            return magnitude;
+        } else if (sign >= 0 &&
+                   magnitude == Long.MIN_VALUE) {
+            throw new MathArithmeticException(LocalizedFormats.OVERFLOW);
+        } else {
+            return (long) -magnitude; // Flip sign.
+        }
+    }
+
     /**
      * Returns the <a href="http://mathworld.wolfram.com/Sign.html"> sign</a>
      * for int value {@code x}.

src/test/java/org/apache/commons/math/util/FastMathTest.java

@@ -1089,4 +1089,20 @@ public class FastMathTest {
         Assert.assertEquals(0, FastMath.log(0, 10), 0);
         Assert.assertEquals(Double.NEGATIVE_INFINITY, FastMath.log(10, 0), 0);
     }
+
+    @Test
+    public void testIndicatorDouble() {
+        double delta = 0.0;
+        Assert.assertEquals(1.0, FastMath.copySign(1d, 2.0), delta);
+        Assert.assertEquals(1.0, FastMath.copySign(1d, 0.0), delta);
+        Assert.assertEquals(-1.0, FastMath.copySign(1d, -2.0), delta);
+    }
+
+    @Test
+    public void testIndicatorFloat() {
+        float delta = 0.0F;
+        Assert.assertEquals(1.0F, FastMath.copySign(1d, 2.0F), delta);
+        Assert.assertEquals(1.0F, FastMath.copySign(1d, 0.0F), delta);
+        Assert.assertEquals(-1.0F, FastMath.copySign(1d, -2.0F), delta);
+    }
 }

src/test/java/org/apache/commons/math/util/MathUtilsTest.java

@@ -102,47 +102,30 @@ public final class MathUtilsTest {
 
     @Test
     public void testIndicatorByte() {
-        Assert.assertEquals((byte)1, MathUtils.indicator((byte)2));
+        Assert.assertEquals((byte)1, MathUtils.copySign((byte)1, (byte)2));
-        Assert.assertEquals((byte)1, MathUtils.indicator((byte)0));
+        Assert.assertEquals((byte)1, MathUtils.copySign((byte)1, (byte)0));
-        Assert.assertEquals((byte)(-1), MathUtils.indicator((byte)(-2)));
+        Assert.assertEquals((byte)(-1), MathUtils.copySign((byte)1, (byte)(-2)));
-    }
-
-    @Test
-    public void testIndicatorDouble() {
-        double delta = 0.0;
-        Assert.assertEquals(1.0, MathUtils.indicator(2.0), delta);
-        Assert.assertEquals(1.0, MathUtils.indicator(0.0), delta);
-        Assert.assertEquals(-1.0, MathUtils.indicator(-2.0), delta);
-        Assert.assertTrue(Double.isNaN(MathUtils.indicator(Double.NaN)));
-    }
-
-    @Test
-    public void testIndicatorFloat() {
-        float delta = 0.0F;
-        Assert.assertEquals(1.0F, MathUtils.indicator(2.0F), delta);
-        Assert.assertEquals(1.0F, MathUtils.indicator(0.0F), delta);
-        Assert.assertEquals(-1.0F, MathUtils.indicator(-2.0F), delta);
     }
 
     @Test
     public void testIndicatorInt() {
-        Assert.assertEquals(1, MathUtils.indicator((2)));
+        Assert.assertEquals(1, MathUtils.copySign(1, 2));
-        Assert.assertEquals(1, MathUtils.indicator((0)));
+        Assert.assertEquals(1, MathUtils.copySign(1, 0));
-        Assert.assertEquals((-1), MathUtils.indicator((-2)));
+        Assert.assertEquals((-1), MathUtils.copySign(1, -2));
     }
 
     @Test
     public void testIndicatorLong() {
-        Assert.assertEquals(1L, MathUtils.indicator(2L));
+        Assert.assertEquals(1L, MathUtils.copySign(1L, 2L));
-        Assert.assertEquals(1L, MathUtils.indicator(0L));
+        Assert.assertEquals(1L, MathUtils.copySign(1L, 0L));
-        Assert.assertEquals(-1L, MathUtils.indicator(-2L));
+        Assert.assertEquals(-1L, MathUtils.copySign(1L, -2L));
     }
 
     @Test
     public void testIndicatorShort() {
-        Assert.assertEquals((short)1, MathUtils.indicator((short)2));
+        Assert.assertEquals((short)1, MathUtils.copySign((short)1, (short)2));
-        Assert.assertEquals((short)1, MathUtils.indicator((short)0));
+        Assert.assertEquals((short)1, MathUtils.copySign((short)1, (short)0));
-        Assert.assertEquals((short)(-1), MathUtils.indicator((short)(-2)));
+        Assert.assertEquals((short)(-1), MathUtils.copySign((short)1, (short)(-2)));
     }
 
     @Test