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Posted to commits@harmony.apache.org by te...@apache.org on 2009/05/02 10:09:57 UTC
svn commit: r770909 [7/10] - in
/harmony/enhanced/classlib/trunk/modules/luni/src/main/java/java/lang: ./
ref/ reflect/
Modified: harmony/enhanced/classlib/trunk/modules/luni/src/main/java/java/lang/StrictMath.java
URL: http://svn.apache.org/viewvc/harmony/enhanced/classlib/trunk/modules/luni/src/main/java/java/lang/StrictMath.java?rev=770909&r1=770908&r2=770909&view=diff
==============================================================================
--- harmony/enhanced/classlib/trunk/modules/luni/src/main/java/java/lang/StrictMath.java (original)
+++ harmony/enhanced/classlib/trunk/modules/luni/src/main/java/java/lang/StrictMath.java Sat May 2 08:09:50 2009
@@ -20,19 +20,32 @@
import java.util.Random;
/**
- * Class StrictMath provides various numeric operations using the standards set
- * by the known "Freely Distributable Math Library" (fdlibm). The standard is
- * set by the January 4th, 1995 version of the library.
+ * Class StrictMath provides basic math constants and operations such as
+ * trigonometric functions, hyperbolic functions, exponential, logarithms, etc.
+ * <p>
+ * In contrast to class {@link Math}, the methods in this class return exactly
+ * the same results on all platforms. Algorithms based on these methods thus
+ * behave the same (e.g. regarding numerical convergence) on all platforms,
+ * complying with the slogan "write once, run everywhere". On the other side,
+ * the implementation of class StrictMath may be less efficient than that of
+ * class Math, as class StrictMath cannot utilize platform specific features
+ * such as an extended precision math co-processors.
+ * <p>
+ * The methods in this class are specified using the "Freely Distributable Math
+ * Library" (fdlibm), version 5.3.
+ * <p>
+ * <a href="http://www.netlib.org/fdlibm/">http://www.netlib.org/fdlibm/</a>
*/
public final class StrictMath {
/**
- * Standard math constant
+ * The double value closest to e, the base of the natural logarithm.
*/
public final static double E = Math.E;
/**
- * Standard math constant
+ * The double value closest to pi, the ratio of a circle's circumference to
+ * its diameter.
*/
public final static double PI = Math.PI;
@@ -45,235 +58,433 @@
}
/**
- * Answers the absolute value of the argument.
- *
- * @param d
- * the value to be converted
- * @return the argument if it is positive, otherwise the negation of the
- * argument.
- */
+ * Returns the absolute value of the argument.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code abs(-0.0) = +0.0}</li>
+ * <li>{@code abs(+infinity) = +infinity}</li>
+ * <li>{@code abs(-infinity) = +infinity}</li>
+ * <li>{@code abs(NaN) = NaN}</li>
+ * </ul>
+ *
+ * @param d
+ * the value whose absolute value has to be computed.
+ * @return the absolute value of the argument.
+ */
public static double abs(double d) {
long bits = Double.doubleToLongBits(d);
bits &= 0x7fffffffffffffffL;
return Double.longBitsToDouble(bits);
}
- /**
- * Answers the absolute value of the argument.
- *
- * @param f
- * the value to be converted
- * @return the argument if it is positive, otherwise the negation of the
- * argument.
- */
+ /**
+ * Returns the absolute value of the argument.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code abs(-0.0) = +0.0}</li>
+ * <li>{@code abs(+infinity) = +infinity}</li>
+ * <li>{@code abs(-infinity) = +infinity}</li>
+ * <li>{@code abs(NaN) = NaN}</li>
+ * </ul>
+ *
+ * @param f
+ * the value whose absolute value has to be computed.
+ * @return the argument if it is positive, otherwise the negation of the
+ * argument.
+ */
public static float abs(float f) {
int bits = Float.floatToIntBits(f);
bits &= 0x7fffffff;
return Float.intBitsToFloat(bits);
}
- /**
- * Answers the absolute value of the argument.
- *
- * @param i
- * the value to be converted
- * @return the argument if it is positive, otherwise the negation of the
- * argument.
- */
+ /**
+ * Returns the absolute value of the argument.
+ * <p>
+ * If the argument is {@code Integer.MIN_VALUE}, {@code Integer.MIN_VALUE}
+ * is returned.
+ *
+ * @param i
+ * the value whose absolute value has to be computed.
+ * @return the argument if it is positive, otherwise the negation of the
+ * argument.
+ */
public static int abs(int i) {
return i >= 0 ? i : -i;
}
- /**
- * Answers the absolute value of the argument.
- *
- * @param l
- * the value to be converted
- * @return the argument if it is positive, otherwise the negation of the
- * argument.
- */
+ /**
+ * Returns the absolute value of the argument.
+ * <p>
+ * If the argument is {@code Long.MIN_VALUE}, {@code Long.MIN_VALUE} is
+ * returned.
+ *
+ * @param l
+ * the value whose absolute value has to be computed.
+ * @return the argument if it is positive, otherwise the negation of the
+ * argument.
+ */
public static long abs(long l) {
return l >= 0 ? l : -l;
}
- /**
- * Answers the closest double approximation of the arc cosine of the
- * argument
- *
- * @param d
- * the value to compute acos of
- * @return the arc cosine of the argument.
- */
+ /**
+ * Returns the closest double approximation of the arc cosine of the
+ * argument within the range {@code [0..pi]}.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code acos((anything > 1) = NaN}</li>
+ * <li>{@code acos((anything < -1) = NaN}</li>
+ * <li>{@code acos(NaN) = NaN}</li>
+ * </ul>
+ *
+ * @param d
+ * the value to compute arc cosine of.
+ * @return the arc cosine of the argument.
+ */
public static native double acos(double d);
- /**
- * Answers the closest double approximation of the arc sine of the argument
- *
- * @param d
- * the value to compute asin of
- * @return the arc sine of the argument.
- */
+ /**
+ * Returns the closest double approximation of the arc sine of the argument
+ * within the range {@code [-pi/2..pi/2]}.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code asin((anything > 1)) = NaN}</li>
+ * <li>{@code asin((anything < -1)) = NaN}</li>
+ * <li>{@code asin(NaN) = NaN}</li>
+ * </ul>
+ *
+ * @param d
+ * the value whose arc sine has to be computed.
+ * @return the arc sine of the argument.
+ */
public static native double asin(double d);
- /**
- * Answers the closest double approximation of the arc tangent of the
- * argument
- *
- * @param d
- * the value to compute atan of
- * @return the arc tangent of the argument.
- */
+ /**
+ * Returns the closest double approximation of the arc tangent of the
+ * argument within the range {@code [-pi/2..pi/2]}.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code atan(+0.0) = +0.0}</li>
+ * <li>{@code atan(-0.0) = -0.0}</li>
+ * <li>{@code atan(+infinity) = +pi/2}</li>
+ * <li>{@code atan(-infinity) = -pi/2}</li>
+ * <li>{@code atan(NaN) = NaN}</li>
+ * </ul>
+ *
+ * @param d
+ * the value whose arc tangent has to be computed.
+ * @return the arc tangent of the argument.
+ */
public static native double atan(double d);
- /**
- * Answers the closest double approximation of the arc tangent of the result
- * of dividing the first argument by the second argument.
- *
- * @param d1
- * the numerator of the value to compute atan of
- * @param d2
- * the denominator of the value to compute atan of
- * @return the arc tangent of d1/d2.
- */
- public static native double atan2(double d1, double d2);
+ /**
+ * Returns the closest double approximation of the arc tangent of
+ * {@code y/x} within the range {@code [-pi..pi]}. This is the angle of the
+ * polar representation of the rectangular coordinates (x,y).
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code atan2((anything), NaN ) = NaN;}</li>
+ * <li>{@code atan2(NaN , (anything) ) = NaN;}</li>
+ * <li>{@code atan2(+0.0, +(anything but NaN)) = +0.0}</li>
+ * <li>{@code atan2(-0.0, +(anything but NaN)) = -0.0}</li>
+ * <li>{@code atan2(+0.0, -(anything but NaN)) = +pi}</li>
+ * <li>{@code atan2(-0.0, -(anything but NaN)) = -pi}</li>
+ * <li>{@code atan2(+(anything but 0 and NaN), 0) = +pi/2}</li>
+ * <li>{@code atan2(-(anything but 0 and NaN), 0) = -pi/2}</li>
+ * <li>{@code atan2(+(anything but infinity and NaN), +infinity)} {@code =}
+ * {@code +0.0}</li>
+ * <li>{@code atan2(-(anything but infinity and NaN), +infinity)} {@code =}
+ * {@code -0.0}</li>
+ * <li>{@code atan2(+(anything but infinity and NaN), -infinity) = +pi}</li>
+ * <li>{@code atan2(-(anything but infinity and NaN), -infinity) = -pi}</li>
+ * <li>{@code atan2(+infinity, +infinity ) = +pi/4}</li>
+ * <li>{@code atan2(-infinity, +infinity ) = -pi/4}</li>
+ * <li>{@code atan2(+infinity, -infinity ) = +3pi/4}</li>
+ * <li>{@code atan2(-infinity, -infinity ) = -3pi/4}</li>
+ * <li>{@code atan2(+infinity, (anything but,0, NaN, and infinity))}
+ * {@code =} {@code +pi/2}</li>
+ * <li>{@code atan2(-infinity, (anything but,0, NaN, and infinity))}
+ * {@code =} {@code -pi/2}</li>
+ * </ul>
+ *
+ * @param y
+ * the numerator of the value whose atan has to be computed.
+ * @param x
+ * the denominator of the value whose atan has to be computed.
+ * @return the arc tangent of {@code y/x}.
+ */
+ public static native double atan2(double y, double x);
- /**
- * Answers the closest double approximation of the cube root of the
- * argument.
- *
+ /**
+ * Returns the closest double approximation of the cube root of the
+ * argument.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code cbrt(+0.0) = +0.0}</li>
+ * <li>{@code cbrt(-0.0) = -0.0}</li>
+ * <li>{@code cbrt(+infinity) = +infinity}</li>
+ * <li>{@code cbrt(-infinity) = -infinity}</li>
+ * <li>{@code cbrt(NaN) = NaN}</li>
+ * </ul>
+ *
* @param d
- * the value to compute cube root of
+ * the value whose cube root has to be computed.
* @return the cube root of the argument.
*/
public static native double cbrt(double d);
- /**
- * Answers the double conversion of the most negative (i.e. closest to
- * negative infinity) integer value which is greater than the argument.
- *
- * @param d
- * the value to be converted
- * @return the ceiling of the argument.
- */
+ /**
+ * Returns the double conversion of the most negative (closest to negative
+ * infinity) integer value which is greater than the argument.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code ceil(+0.0) = +0.0}</li>
+ * <li>{@code ceil(-0.0) = -0.0}</li>
+ * <li>{@code ceil((anything in range (-1,0)) = -0.0}</li>
+ * <li>{@code ceil(+infinity) = +infinity}</li>
+ * <li>{@code ceil(-infinity) = -infinity}</li>
+ * <li>{@code ceil(NaN) = NaN}</li>
+ * </ul>
+ *
+ * @param d
+ * the value whose closest integer value has to be computed.
+ * @return the ceiling of the argument.
+ */
public static native double ceil(double d);
/**
- * Answers the closest double approximation of the hyperbolic cosine of the
+ * Returns the closest double approximation of the hyperbolic cosine of the
* argument.
- *
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code cosh(+infinity) = +infinity}</li>
+ * <li>{@code cosh(-infinity) = +infinity}</li>
+ * <li>{@code cosh(NaN) = NaN}</li>
+ * </ul>
+ *
* @param d
- * the value to compute hyperbolic cosine of
+ * the value whose hyperbolic cosine has to be computed.
* @return the hyperbolic cosine of the argument.
*/
public static native double cosh(double d);
- /**
- * Answers the closest double approximation of the cosine of the argument
- *
- * @param d
- * the value to compute cos of
- * @return the cosine of the argument.
- */
- public static native double cos(double d);
+ /**
+ * Returns the closest double approximation of the cosine of the argument.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code cos(+infinity) = NaN}</li>
+ * <li>{@code cos(-infinity) = NaN}</li>
+ * <li>{@code cos(NaN) = NaN}</li>
+ * </ul>
+ *
+ * @param d
+ * the angle whose cosine has to be computed, in radians.
+ * @return the cosine of the argument.
+ */
+ public static native double cos(double d);
- /**
- * Answers the closest double approximation of the raising "e" to the power
- * of the argument
- *
- * @param d
- * the value to compute the exponential of
- * @return the exponential of the argument.
- */
- public static native double exp(double d);
+ /**
+ * Returns the closest double approximation of the raising "e" to the power
+ * of the argument.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code exp(+infinity) = +infinity}</li>
+ * <li>{@code exp(-infinity) = +0.0}</li>
+ * <li>{@code exp(NaN) = NaN}</li>
+ * </ul>
+ *
+ * @param d
+ * the value whose exponential has to be computed.
+ * @return the exponential of the argument.
+ */
+ public static native double exp(double d);
/**
- * Answers the closest double approximation of <i>e</i><sup>d</sup> - 1.
- * If the argument is very close to 0, it is much more accurate to use
- * expm1(d)+1 than exp(d).
- *
+ * Returns the closest double approximation of <i>{@code e}</i><sup>
+ * {@code d}</sup>{@code - 1}. If the argument is very close to 0, it is
+ * much more accurate to use {@code expm1(d)+1} than {@code exp(d)} (due to
+ * cancellation of significant digits).
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code expm1(+0.0) = +0.0}</li>
+ * <li>{@code expm1(-0.0) = -0.0}</li>
+ * <li>{@code expm1(+infinity) = +infinity}</li>
+ * <li>{@code expm1(-infinity) = -1.0}</li>
+ * <li>{@code expm1(NaN) = NaN}</li>
+ * </ul>
+ *
* @param d
- * the value to compute the <i>e</i><sup>d</sup> - 1 of
- * @return the <i>e</i><sup>d</sup> - 1 value of the argument.
+ * the value to compute the <i>{@code e}</i><sup>{@code d}</sup>
+ * {@code - 1} of.
+ * @return the <i>{@code e}</i><sup>{@code d}</sup>{@code - 1} value
+ * of the argument.
*/
public static native double expm1(double d);
- /**
- * Answers the double conversion of the most positive (i.e. closest to
- * positive infinity) integer value which is less than the argument.
- *
- *
- * @param d
- * the value to be converted
- * @return the ceiling of the argument.
- */
- public static native double floor(double d);
+ /**
+ * Returns the double conversion of the most positive (closest to
+ * positive infinity) integer value which is less than the argument.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code floor(+0.0) = +0.0}</li>
+ * <li>{@code floor(-0.0) = -0.0}</li>
+ * <li>{@code floor(+infinity) = +infinity}</li>
+ * <li>{@code floor(-infinity) = -infinity}</li>
+ * <li>{@code floor(NaN) = NaN}</li>
+ * </ul>
+ *
+ * @param d the value whose closest integer value has to be computed.
+ * @return the floor of the argument.
+ */
+ public static native double floor(double d);
/**
- * Answers sqrt(<i>x</i><sup>2</sup>+<i>y</i><sup>2</sup>). The
- * final result is without medium underflow or overflow.
- *
+ * Returns {@code sqrt(}<i>{@code x}</i><sup>{@code 2}</sup>{@code +}
+ * <i> {@code y}</i><sup>{@code 2}</sup>{@code )}. The final result is
+ * without medium underflow or overflow.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code hypot(+infinity, (anything including NaN)) = +infinity}</li>
+ * <li>{@code hypot(-infinity, (anything including NaN)) = +infinity}</li>
+ * <li>{@code hypot((anything including NaN), +infinity) = +infinity}</li>
+ * <li>{@code hypot((anything including NaN), -infinity) = +infinity}</li>
+ * <li>{@code hypot(NaN, NaN) = NaN}</li>
+ * </ul>
+ *
* @param x
- * a double number
+ * a double number.
* @param y
- * a double number
- * @return the sqrt(<i>x</i><sup>2</sup>+<i>y</i><sup>2</sup>) value
- * of the arguments.
+ * a double number.
+ * @return the {@code sqrt(}<i>{@code x}</i><sup>{@code 2}</sup>{@code +}
+ * <i> {@code y}</i><sup>{@code 2}</sup>{@code )} value of the
+ * arguments.
*/
public static native double hypot(double x, double y);
- /**
- * Answers the remainder of dividing the first argument by the second using
- * the IEEE 754 rules.
- *
- * @param d1
- * the numerator of the operation
- * @param d2
- * the denominator of the operation
- * @return the result of d1/d2.
- */
- public static native double IEEEremainder(double d1, double d2);
+ /**
+ * Returns the remainder of dividing {@code x} by {@code y} using the IEEE
+ * 754 rules. The result is {@code x-round(x/p)*p} where {@code round(x/p)}
+ * is the nearest integer (rounded to even), but without numerical
+ * cancellation problems.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code IEEEremainder((anything), 0) = NaN}</li>
+ * <li>{@code IEEEremainder(+infinity, (anything)) = NaN}</li>
+ * <li>{@code IEEEremainder(-infinity, (anything)) = NaN}</li>
+ * <li>{@code IEEEremainder(NaN, (anything)) = NaN}</li>
+ * <li>{@code IEEEremainder((anything), NaN) = NaN}</li>
+ * <li>{@code IEEEremainder(x, +infinity) = x } where x is anything but
+ * +/-infinity</li>
+ * <li>{@code IEEEremainder(x, -infinity) = x } where x is anything but
+ * +/-infinity</li>
+ * </ul>
+ *
+ * @param x
+ * the numerator of the operation.
+ * @param y
+ * the denominator of the operation.
+ * @return the IEEE754 floating point reminder of of {@code x/y}.
+ */
+ public static native double IEEEremainder(double x, double y);
- /**
- * Answers the closest double approximation of the natural logarithm of the
- * argument
- *
- * @param d
- * the value to compute the log of
- * @return the natural logarithm of the argument.
- */
- public static native double log(double d);
+ /**
+ * Returns the closest double approximation of the natural logarithm of the
+ * argument.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code log(+0.0) = -infinity}</li>
+ * <li>{@code log(-0.0) = -infinity}</li>
+ * <li>{@code log((anything < 0) = NaN}</li>
+ * <li>{@code log(+infinity) = +infinity}</li>
+ * <li>{@code log(-infinity) = NaN}</li>
+ * <li>{@code log(NaN) = NaN}</li>
+ * </ul>
+ *
+ * @param d
+ * the value whose log has to be computed.
+ * @return the natural logarithm of the argument.
+ */
+ public static native double log(double d);
/**
- * Answers the logarithm of the argument and the base is 10.
- *
+ * Returns the closest double approximation of the base 10 logarithm of the
+ * argument.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code log10(+0.0) = -infinity}</li>
+ * <li>{@code log10(-0.0) = -infinity}</li>
+ * <li>{@code log10((anything < 0) = NaN}</li>
+ * <li>{@code log10(+infinity) = +infinity}</li>
+ * <li>{@code log10(-infinity) = NaN}</li>
+ * <li>{@code log10(NaN) = NaN}</li>
+ * </ul>
+ *
* @param d
- * the value to compute the base 10 log of
- * @return the base 10 logarithm of the argument.
+ * the value whose base 10 log has to be computed.
+ * @return the natural logarithm of the argument.
*/
public static native double log10(double d);
/**
- * Answers the closest double approximation of the natural logarithm of the
+ * Returns the closest double approximation of the natural logarithm of the
* sum of the argument and 1. If the argument is very close to 0, it is much
- * more accurate to use log1p(d) than log(1.0+d).
- *
+ * more accurate to use {@code log1p(d)} than {@code log(1.0+d)} (due to
+ * numerical cancellation).
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code log1p(+0.0) = +0.0}</li>
+ * <li>{@code log1p(-0.0) = -0.0}</li>
+ * <li>{@code log1p((anything < 1)) = NaN}</li>
+ * <li>{@code log1p(-1.0) = -infinity}</li>
+ * <li>{@code log1p(+infinity) = +infinity}</li>
+ * <li>{@code log1p(-infinity) = NaN}</li>
+ * <li>{@code log1p(NaN) = NaN}</li>
+ * </ul>
+ *
* @param d
- * the value to compute the ln(1+d) of
+ * the value to compute the {@code ln(1+d)} of.
* @return the natural logarithm of the sum of the argument and 1.
*/
public static native double log1p(double d);
- /**
- * Answers the most positive (i.e. closest to positive infinity) of the two
- * arguments.
- *
- * @param d1
- * the first argument to check
- * @param d2
- * the second argument
- * @return the larger of d1 and d2.
- */
+ /**
+ * Returns the most positive (closest to positive infinity) of the two
+ * arguments.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code max(NaN, (anything)) = NaN}</li>
+ * <li>{@code max((anything), NaN) = NaN}</li>
+ * <li>{@code max(+0.0, -0.0) = +0.0}</li>
+ * <li>{@code max(-0.0, +0.0) = +0.0}</li>
+ * </ul>
+ *
+ * @param d1
+ * the first argument.
+ * @param d2
+ * the second argument.
+ * @return the larger of {@code d1} and {@code d2}.
+ */
public static double max(double d1, double d2) {
if (d1 > d2)
return d1;
@@ -289,16 +500,24 @@
return d1;
}
- /**
- * Answers the most positive (i.e. closest to positive infinity) of the two
- * arguments.
- *
- * @param f1
- * the first argument to check
- * @param f2
- * the second argument
- * @return the larger of f1 and f2.
- */
+ /**
+ * Returns the most positive (closest to positive infinity) of the two
+ * arguments.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code max(NaN, (anything)) = NaN}</li>
+ * <li>{@code max((anything), NaN) = NaN}</li>
+ * <li>{@code max(+0.0, -0.0) = +0.0}</li>
+ * <li>{@code max(-0.0, +0.0) = +0.0}</li>
+ * </ul>
+ *
+ * @param f1
+ * the first argument.
+ * @param f2
+ * the second argument.
+ * @return the larger of {@code f1} and {@code f2}.
+ */
public static float max(float f1, float f2) {
if (f1 > f2)
return f1;
@@ -314,44 +533,52 @@
return f1;
}
- /**
- * Answers the most positive (i.e. closest to positive infinity) of the two
- * arguments.
- *
- * @param i1
- * the first argument to check
- * @param i2
- * the second argument
- * @return the larger of i1 and i2.
- */
+ /**
+ * Returns the most positive (closest to positive infinity) of the two
+ * arguments.
+ *
+ * @param i1
+ * the first argument.
+ * @param i2
+ * the second argument.
+ * @return the larger of {@code i1} and {@code i2}.
+ */
public static int max(int i1, int i2) {
return i1 > i2 ? i1 : i2;
}
- /**
- * Answers the most positive (i.e. closest to positive infinity) of the two
- * arguments.
- *
- * @param l1
- * the first argument to check
- * @param l2
- * the second argument
- * @return the larger of l1 and l2.
- */
+ /**
+ * Returns the most positive (closest to positive infinity) of the two
+ * arguments.
+ *
+ * @param l1
+ * the first argument.
+ * @param l2
+ * the second argument.
+ * @return the larger of {@code l1} and {@code l2}.
+ */
public static long max(long l1, long l2) {
return l1 > l2 ? l1 : l2;
}
- /**
- * Answers the most negative (i.e. closest to negative infinity) of the two
- * arguments.
- *
- * @param d1
- * the first argument to check
- * @param d2
- * the second argument
- * @return the smaller of d1 and d2.
- */
+ /**
+ * Returns the most negative (closest to negative infinity) of the two
+ * arguments.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code min(NaN, (anything)) = NaN}</li>
+ * <li>{@code min((anything), NaN) = NaN}</li>
+ * <li>{@code min(+0.0, -0.0) = -0.0}</li>
+ * <li>{@code min(-0.0, +0.0) = -0.0}</li>
+ * </ul>
+ *
+ * @param d1
+ * the first argument.
+ * @param d2
+ * the second argument.
+ * @return the smaller of {@code d1} and {@code d2}.
+ */
public static double min(double d1, double d2) {
if (d1 > d2)
return d2;
@@ -367,16 +594,24 @@
return d1;
}
- /**
- * Answers the most negative (i.e. closest to negative infinity) of the two
- * arguments.
- *
- * @param f1
- * the first argument to check
- * @param f2
- * the second argument
- * @return the smaller of f1 and f2.
- */
+ /**
+ * Returns the most negative (closest to negative infinity) of the two
+ * arguments.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code min(NaN, (anything)) = NaN}</li>
+ * <li>{@code min((anything), NaN) = NaN}</li>
+ * <li>{@code min(+0.0, -0.0) = -0.0}</li>
+ * <li>{@code min(-0.0, +0.0) = -0.0}</li>
+ * </ul>
+ *
+ * @param f1
+ * the first argument.
+ * @param f2
+ * the second argument.
+ * @return the smaller of {@code f1} and {@code f2}.
+ */
public static float min(float f1, float f2) {
if (f1 > f2)
return f2;
@@ -392,74 +627,124 @@
return f1;
}
- /**
- * Answers the most negative (i.e. closest to negative infinity) of the two
- * arguments.
- *
- * @param i1
- * the first argument to check
- * @param i2
- * the second argument
- * @return the smaller of i1 and i2.
- */
+ /**
+ * Returns the most negative (closest to negative infinity) of the two
+ * arguments.
+ *
+ * @param i1
+ * the first argument.
+ * @param i2
+ * the second argument.
+ * @return the smaller of {@code i1} and {@code i2}.
+ */
public static int min(int i1, int i2) {
return i1 < i2 ? i1 : i2;
}
- /**
- * Answers the most negative (i.e. closest to negative infinity) of the two
- * arguments.
- *
- * @param l1
- * the first argument to check
- * @param l2
- * the second argument
- * @return the smaller of l1 and l2.
- */
+ /**
+ * Returns the most negative (closest to negative infinity) of the two
+ * arguments.
+ *
+ * @param l1
+ * the first argument.
+ * @param l2
+ * the second argument.
+ * @return the smaller of {@code l1} and {@code l2}.
+ */
public static long min(long l1, long l2) {
return l1 < l2 ? l1 : l2;
}
- /**
- * Answers the closest double approximation of the result of raising the
- * first argument to the power of the second.
- *
- * @param d1
- * the base of the operation.
- * @param d2
- * the exponent of the operation.
- * @return d1 to the power of d2
- */
- public static native double pow(double d1, double d2);
+ /**
+ * Returns the closest double approximation of the result of raising
+ * {@code x} to the power of {@code y}.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code pow((anything), +0.0) = 1.0}</li>
+ * <li>{@code pow((anything), -0.0) = 1.0}</li>
+ * <li>{@code pow(x, 1.0) = x}</li>
+ * <li>{@code pow((anything), NaN) = NaN}</li>
+ * <li>{@code pow(NaN, (anything except 0)) = NaN}</li>
+ * <li>{@code pow(+/-(|x| > 1), +infinity) = +infinity}</li>
+ * <li>{@code pow(+/-(|x| > 1), -infinity) = +0.0}</li>
+ * <li>{@code pow(+/-(|x| < 1), +infinity) = +0.0}</li>
+ * <li>{@code pow(+/-(|x| < 1), -infinity) = +infinity}</li>
+ * <li>{@code pow(+/-1.0 , +infinity) = NaN}</li>
+ * <li>{@code pow(+/-1.0 , -infinity) = NaN}</li>
+ * <li>{@code pow(+0.0, (+anything except 0, NaN)) = +0.0}</li>
+ * <li>{@code pow(-0.0, (+anything except 0, NaN, odd integer)) = +0.0}</li>
+ * <li>{@code pow(+0.0, (-anything except 0, NaN)) = +infinity}</li>
+ * <li>{@code pow(-0.0, (-anything except 0, NAN, odd integer))} {@code =}
+ * {@code +infinity}</li>
+ * <li>{@code pow(-0.0, (odd integer)) = -pow( +0 , (odd integer) )}</li>
+ * <li>{@code pow(+infinity, (+anything except 0, NaN)) = +infinity}</li>
+ * <li>{@code pow(+infinity, (-anything except 0, NaN)) = +0.0}</li>
+ * <li>{@code pow(-infinity, (anything)) = -pow(0, (-anything))}</li>
+ * <li>{@code pow((-anything), (integer))} {@code =}
+ * {@code pow(-1,(integer))*pow(+anything,integer)}</li>
+ * <li>{@code pow((-anything except 0 and infinity), (non-integer))}
+ * {@code =} {@code NAN}</li>
+ * </ul>
+ *
+ * @param x
+ * the base of the operation.
+ * @param y
+ * the exponent of the operation.
+ * @return {@code x} to the power of {@code y}.
+ */
+ public static native double pow(double x, double y);
- /**
- * Returns a pseudo-random number between 0.0 and 1.0.
- *
- * @return a pseudo-random number
- */
- public static double random() {
+ /**
+ * Returns a pseudo-random number between 0.0 (inclusive) and 1.0
+ * (exclusive).
+ *
+ * @return a pseudo-random number.
+ */
+ public static double random() {
if (random == null)
random = new Random();
return random.nextDouble();
}
- /**
- * Answers the double conversion of the result of rounding the argument to
- * an integer.
- *
- * @param d
- * the value to be converted
- * @return the closest integer to the argument (as a double).
- */
- public static native double rint(double d);
+ /**
+ * Returns the double conversion of the result of rounding the argument to
+ * an integer. Tie breaks are rounded towards even.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code rint(+0.0) = +0.0}</li>
+ * <li>{@code rint(-0.0) = -0.0}</li>
+ * <li>{@code rint(+infinity) = +infinity}</li>
+ * <li>{@code rint(-infinity) = -infinity}</li>
+ * <li>{@code rint(NaN) = NaN}</li>
+ * </ul>
+ *
+ * @param d
+ * the value to be rounded.
+ * @return the closest integer to the argument (as a double).
+ */
+ public static native double rint(double d);
- /**
- * Answers the result of rounding the argument to an integer.
- *
- * @param d
- * the value to be converted
- * @return the closest integer to the argument.
- */
+ /**
+ * Returns the result of rounding the argument to an integer. The result is
+ * equivalent to {@code (long) Math.floor(d+0.5)}.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code round(+0.0) = +0.0}</li>
+ * <li>{@code round(-0.0) = +0.0}</li>
+ * <li>{@code round((anything > Long.MAX_VALUE) = Long.MAX_VALUE}</li>
+ * <li>{@code round((anything < Long.MIN_VALUE) = Long.MIN_VALUE}</li>
+ * <li>{@code round(+infinity) = Long.MAX_VALUE}</li>
+ * <li>{@code round(-infinity) = Long.MIN_VALUE}</li>
+ * <li>{@code round(NaN) = +0.0}</li>
+ * </ul>
+ *
+ * @param d
+ * the value to be rounded.
+ * @return the closest integer to the argument.
+ */
public static long round(double d) {
// check for NaN
if (d != d)
@@ -467,13 +752,25 @@
return (long) Math.floor(d + 0.5d);
}
- /**
- * Answers the result of rounding the argument to an integer.
- *
- * @param f
- * the value to be converted
- * @return the closest integer to the argument.
- */
+ /**
+ * Returns the result of rounding the argument to an integer. The result is
+ * equivalent to {@code (int) Math.floor(f+0.5)}.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code round(+0.0) = +0.0}</li>
+ * <li>{@code round(-0.0) = +0.0}</li>
+ * <li>{@code round((anything > Integer.MAX_VALUE) = Integer.MAX_VALUE}</li>
+ * <li>{@code round((anything < Integer.MIN_VALUE) = Integer.MIN_VALUE}</li>
+ * <li>{@code round(+infinity) = Integer.MAX_VALUE}</li>
+ * <li>{@code round(-infinity) = Integer.MIN_VALUE}</li>
+ * <li>{@code round(NaN) = +0.0}</li>
+ * </ul>
+ *
+ * @param f
+ * the value to be rounded.
+ * @return the closest integer to the argument.
+ */
public static int round(float f) {
// check for NaN
if (f != f)
@@ -482,12 +779,22 @@
}
/**
- * Answers the signum function of the argument. If the argument is less than
- * zero, it answers -1.0. If greater than zero, 1.0 is returned. It returns
- * zero if the argument is also zero.
- *
+ * Returns the signum function of the argument. If the argument is less than
+ * zero, it returns -1.0. If the argument is greater than zero, 1.0 is
+ * returned. If the argument is either positive or negative zero, the
+ * argument is returned as result.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code signum(+0.0) = +0.0}</li>
+ * <li>{@code signum(-0.0) = -0.0}</li>
+ * <li>{@code signum(+infinity) = +1.0}</li>
+ * <li>{@code signum(-infinity) = -1.0}</li>
+ * <li>{@code signum(NaN) = NaN}</li>
+ * </ul>
+ *
* @param d
- * the value to compute signum function of
+ * the value whose signum has to be computed.
* @return the value of the signum function.
*/
public static double signum(double d){
@@ -504,12 +811,22 @@
}
/**
- * Answers the signum function of the argument. If the argument is less than
- * zero, it answers -1.0. If greater than zero, 1.0 is returned. It returns
- * zero if the argument is also zero.
- *
+ * Returns the signum function of the argument. If the argument is less than
+ * zero, it returns -1.0. If the argument is greater than zero, 1.0 is
+ * returned. If the argument is either positive or negative zero, the
+ * argument is returned as result.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code signum(+0.0) = +0.0}</li>
+ * <li>{@code signum(-0.0) = -0.0}</li>
+ * <li>{@code signum(+infinity) = +1.0}</li>
+ * <li>{@code signum(-infinity) = -1.0}</li>
+ * <li>{@code signum(NaN) = NaN}</li>
+ * </ul>
+ *
* @param f
- * the value to compute signum function of
+ * the value whose signum has to be computed.
* @return the value of the signum function.
*/
public static float signum(float f){
@@ -526,82 +843,157 @@
}
/**
- * Answers the closest double approximation of the hyperbolic sine of the
- * argument.
- *
+ * Returns the closest double approximation of the hyperbolic sine of the
+ * argument.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code sinh(+0.0) = +0.0}</li>
+ * <li>{@code sinh(-0.0) = -0.0}</li>
+ * <li>{@code sinh(+infinity) = +infinity}</li>
+ * <li>{@code sinh(-infinity) = -infinity}</li>
+ * <li>{@code sinh(NaN) = NaN}</li>
+ * </ul>
+ *
* @param d
- * the value to compute hyperbolic sine of
+ * the value whose hyperbolic sine has to be computed.
* @return the hyperbolic sine of the argument.
*/
public static native double sinh(double d);
- /**
- * Answers the closest double approximation of the sine of the argument
- *
- * @param d
- * the value to compute sin of
- * @return the sine of the argument.
- */
- public static native double sin(double d);
+ /**
+ * Returns the closest double approximation of the sine of the argument.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code sin(+0.0) = +0.0}</li>
+ * <li>{@code sin(-0.0) = -0.0}</li>
+ * <li>{@code sin(+infinity) = NaN}</li>
+ * <li>{@code sin(-infinity) = NaN}</li>
+ * <li>{@code sin(NaN) = NaN}</li>
+ * </ul>
+ *
+ * @param d
+ * the angle whose sin has to be computed, in radians.
+ * @return the sine of the argument.
+ */
+ public static native double sin(double d);
- /**
- * Answers the closest double approximation of the square root of the
- * argument
- *
- * @param d
- * the value to compute sqrt of
- * @return the square root of the argument.
- */
- public static native double sqrt(double d);
+ /**
+ * Returns the closest double approximation of the square root of the
+ * argument.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code sqrt(+0.0) = +0.0}</li>
+ * <li>{@code sqrt(-0.0) = -0.0}</li>
+ * <li>{@code sqrt( (anything < 0) ) = NaN}</li>
+ * <li>{@code sqrt(+infinity) = +infinity}</li>
+ * <li>{@code sqrt(NaN) = NaN}</li>
+ * </ul>
+ *
+ * @param d
+ * the value whose square root has to be computed.
+ * @return the square root of the argument.
+ */
+ public static native double sqrt(double d);
- /**
- * Answers the closest double approximation of the tangent of the argument
- *
- * @param d
- * the value to compute tan of
- * @return the tangent of the argument.
- */
- public static native double tan(double d);
+ /**
+ * Returns the closest double approximation of the tangent of the argument.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code tan(+0.0) = +0.0}</li>
+ * <li>{@code tan(-0.0) = -0.0}</li>
+ * <li>{@code tan(+infinity) = NaN}</li>
+ * <li>{@code tan(-infinity) = NaN}</li>
+ * <li>{@code tan(NaN) = NaN}</li>
+ * </ul>
+ *
+ * @param d
+ * the angle whose tangens has to be computed, in radians.
+ * @return the tangent of the argument.
+ */
+ public static native double tan(double d);
/**
- * Answers the closest double approximation of the hyperbolic tangent of the
- * argument. The absolute value is always less than 1.
- *
+ * Returns the closest double approximation of the hyperbolic tangent of the
+ * argument. The absolute value is always less than 1.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code tanh(+0.0) = +0.0}</li>
+ * <li>{@code tanh(-0.0) = -0.0}</li>
+ * <li>{@code tanh(+infinity) = +1.0}</li>
+ * <li>{@code tanh(-infinity) = -1.0}</li>
+ * <li>{@code tanh(NaN) = NaN}</li>
+ * </ul>
+ *
* @param d
- * the value to compute hyperbolic tangent of
- * @return the hyperbolic tangent of the argument.
+ * the value whose hyperbolic tangent has to be computed.
+ * @return the hyperbolic tangent of the argument
*/
public static native double tanh(double d);
- /**
- * Returns the measure in degrees of the supplied radian angle
- *
- * @param angrad
- * an angle in radians
- * @return the degree measure of the angle.
- */
+ /**
+ * Returns the measure in degrees of the supplied radian angle. The result
+ * is {@code angrad * 180 / pi}.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code toDegrees(+0.0) = +0.0}</li>
+ * <li>{@code toDegrees(-0.0) = -0.0}</li>
+ * <li>{@code toDegrees(+infinity) = +infinity}</li>
+ * <li>{@code toDegrees(-infinity) = -infinity}</li>
+ * <li>{@code toDegrees(NaN) = NaN}</li>
+ * </ul>
+ *
+ * @param angrad
+ * an angle in radians.
+ * @return the degree measure of the angle.
+ */
public static double toDegrees(double angrad) {
return angrad * 180d / PI;
}
- /**
- * Returns the measure in radians of the supplied degree angle
- *
- * @param angdeg
- * an angle in degrees
- * @return the radian measure of the angle.
- */
+ /**
+ * Returns the measure in radians of the supplied degree angle. The result
+ * is {@code angdeg / 180 * pi}.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code toRadians(+0.0) = +0.0}</li>
+ * <li>{@code toRadians(-0.0) = -0.0}</li>
+ * <li>{@code toRadians(+infinity) = +infinity}</li>
+ * <li>{@code toRadians(-infinity) = -infinity}</li>
+ * <li>{@code toRadians(NaN) = NaN}</li>
+ * </ul>
+ *
+ * @param angdeg
+ * an angle in degrees.
+ * @return the radian measure of the angle.
+ */
public static double toRadians(double angdeg) {
return angdeg / 180d * PI;
}
/**
- * Answers the argument's ulp. The size of a ulp of a double value is the
- * positive distance between this value and the double value next larger
- * in magnitude. For non-NaN x, ulp(-x) == ulp(x).
- *
+ * Returns the argument's ulp (unit in the last place). The size of a ulp of
+ * a double value is the positive distance between this value and the double
+ * value next larger in magnitude. For non-NaN {@code x},
+ * {@code ulp(-x) == ulp(x)}.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code ulp(+0.0) = Double.MIN_VALUE}</li>
+ * <li>{@code ulp(-0.0) = Double.MIN_VALUE}</li>
+ * <li>{@code ulp(+infintiy) = infinity}</li>
+ * <li>{@code ulp(-infintiy) = infinity}</li>
+ * <li>{@code ulp(NaN) = NaN}</li>
+ * </ul>
+ *
* @param d
- * the floating-point value to compute ulp of
+ * the floating-point value to compute ulp of.
* @return the size of a ulp of the argument.
*/
public static double ulp(double d) {
@@ -616,12 +1008,22 @@
}
/**
- * Answers the argument's ulp. The size of a ulp of a float value is the
- * positive distance between this value and the float value next larger
- * in magnitude. For non-NaN x, ulp(-x) == ulp(x).
- *
+ * Returns the argument's ulp (unit in the last place). The size of a ulp of
+ * a float value is the positive distance between this value and the float
+ * value next larger in magnitude. For non-NaN {@code x},
+ * {@code ulp(-x) == ulp(x)}.
+ * <p>
+ * Special cases:
+ * <ul>
+ * <li>{@code ulp(+0.0) = Float.MIN_VALUE}</li>
+ * <li>{@code ulp(-0.0) = Float.MIN_VALUE}</li>
+ * <li>{@code ulp(+infintiy) = infinity}</li>
+ * <li>{@code ulp(-infintiy) = infinity}</li>
+ * <li>{@code ulp(NaN) = NaN}</li>
+ * </ul>
+ *
* @param f
- * the floating-point value to compute ulp of
+ * the floating-point value to compute ulp of.
* @return the size of a ulp of the argument.
*/
public static float ulp(float f) {