From c8875fb97fc03779a5bba09872227b1d08e5d52a Mon Sep 17 00:00:00 2001 From: tromey Date: Sat, 16 Jul 2005 00:30:23 +0000 Subject: Initial revision git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@102074 138bc75d-0d04-0410-961f-82ee72b054a4 --- libjava/classpath/java/lang/Math.java | 650 ++++++++++++++++++++++++++++++++++ 1 file changed, 650 insertions(+) create mode 100644 libjava/classpath/java/lang/Math.java (limited to 'libjava/classpath/java/lang/Math.java') diff --git a/libjava/classpath/java/lang/Math.java b/libjava/classpath/java/lang/Math.java new file mode 100644 index 00000000000..08081e2523a --- /dev/null +++ b/libjava/classpath/java/lang/Math.java @@ -0,0 +1,650 @@ +/* java.lang.Math -- common mathematical functions, native allowed + Copyright (C) 1998, 2001, 2002, 2003 Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +General Public License for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + + +package java.lang; + +import gnu.classpath.Configuration; + +import java.util.Random; + +/** + * Helper class containing useful mathematical functions and constants. + *

+ * + * Note that angles are specified in radians. Conversion functions are + * provided for your convenience. + * + * @author Paul Fisher + * @author John Keiser + * @author Eric Blake (ebb9@email.byu.edu) + * @since 1.0 + */ +public final class Math +{ + /** + * Math is non-instantiable + */ + private Math() + { + } + + static + { + if (Configuration.INIT_LOAD_LIBRARY) + { + System.loadLibrary("javalang"); + } + } + + /** + * A random number generator, initialized on first use. + */ + private static Random rand; + + /** + * The most accurate approximation to the mathematical constant e: + * 2.718281828459045. Used in natural log and exp. + * + * @see #log(double) + * @see #exp(double) + */ + public static final double E = 2.718281828459045; + + /** + * The most accurate approximation to the mathematical constant pi: + * 3.141592653589793. This is the ratio of a circle's diameter + * to its circumference. + */ + public static final double PI = 3.141592653589793; + + /** + * Take the absolute value of the argument. + * (Absolute value means make it positive.) + *

+ * + * Note that the the largest negative value (Integer.MIN_VALUE) cannot + * be made positive. In this case, because of the rules of negation in + * a computer, MIN_VALUE is what will be returned. + * This is a negative value. You have been warned. + * + * @param i the number to take the absolute value of + * @return the absolute value + * @see Integer#MIN_VALUE + */ + public static int abs(int i) + { + return (i < 0) ? -i : i; + } + + /** + * Take the absolute value of the argument. + * (Absolute value means make it positive.) + *

+ * + * Note that the the largest negative value (Long.MIN_VALUE) cannot + * be made positive. In this case, because of the rules of negation in + * a computer, MIN_VALUE is what will be returned. + * This is a negative value. You have been warned. + * + * @param l the number to take the absolute value of + * @return the absolute value + * @see Long#MIN_VALUE + */ + public static long abs(long l) + { + return (l < 0) ? -l : l; + } + + /** + * Take the absolute value of the argument. + * (Absolute value means make it positive.) + *

+ * + * This is equivalent, but faster than, calling + * Float.intBitsToFloat(0x7fffffff & Float.floatToIntBits(a)). + * + * @param f the number to take the absolute value of + * @return the absolute value + */ + public static float abs(float f) + { + return (f <= 0) ? 0 - f : f; + } + + /** + * Take the absolute value of the argument. + * (Absolute value means make it positive.) + * + * This is equivalent, but faster than, calling + * Double.longBitsToDouble(Double.doubleToLongBits(a) + * << 1) >>> 1);. + * + * @param d the number to take the absolute value of + * @return the absolute value + */ + public static double abs(double d) + { + return (d <= 0) ? 0 - d : d; + } + + /** + * Return whichever argument is smaller. + * + * @param a the first number + * @param b a second number + * @return the smaller of the two numbers + */ + public static int min(int a, int b) + { + return (a < b) ? a : b; + } + + /** + * Return whichever argument is smaller. + * + * @param a the first number + * @param b a second number + * @return the smaller of the two numbers + */ + public static long min(long a, long b) + { + return (a < b) ? a : b; + } + + /** + * Return whichever argument is smaller. If either argument is NaN, the + * result is NaN, and when comparing 0 and -0, -0 is always smaller. + * + * @param a the first number + * @param b a second number + * @return the smaller of the two numbers + */ + public static float min(float a, float b) + { + // this check for NaN, from JLS 15.21.1, saves a method call + if (a != a) + return a; + // no need to check if b is NaN; < will work correctly + // recall that -0.0 == 0.0, but [+-]0.0 - [+-]0.0 behaves special + if (a == 0 && b == 0) + return -(-a - b); + return (a < b) ? a : b; + } + + /** + * Return whichever argument is smaller. If either argument is NaN, the + * result is NaN, and when comparing 0 and -0, -0 is always smaller. + * + * @param a the first number + * @param b a second number + * @return the smaller of the two numbers + */ + public static double min(double a, double b) + { + // this check for NaN, from JLS 15.21.1, saves a method call + if (a != a) + return a; + // no need to check if b is NaN; < will work correctly + // recall that -0.0 == 0.0, but [+-]0.0 - [+-]0.0 behaves special + if (a == 0 && b == 0) + return -(-a - b); + return (a < b) ? a : b; + } + + /** + * Return whichever argument is larger. + * + * @param a the first number + * @param b a second number + * @return the larger of the two numbers + */ + public static int max(int a, int b) + { + return (a > b) ? a : b; + } + + /** + * Return whichever argument is larger. + * + * @param a the first number + * @param b a second number + * @return the larger of the two numbers + */ + public static long max(long a, long b) + { + return (a > b) ? a : b; + } + + /** + * Return whichever argument is larger. If either argument is NaN, the + * result is NaN, and when comparing 0 and -0, 0 is always larger. + * + * @param a the first number + * @param b a second number + * @return the larger of the two numbers + */ + public static float max(float a, float b) + { + // this check for NaN, from JLS 15.21.1, saves a method call + if (a != a) + return a; + // no need to check if b is NaN; > will work correctly + // recall that -0.0 == 0.0, but [+-]0.0 - [+-]0.0 behaves special + if (a == 0 && b == 0) + return a - -b; + return (a > b) ? a : b; + } + + /** + * Return whichever argument is larger. If either argument is NaN, the + * result is NaN, and when comparing 0 and -0, 0 is always larger. + * + * @param a the first number + * @param b a second number + * @return the larger of the two numbers + */ + public static double max(double a, double b) + { + // this check for NaN, from JLS 15.21.1, saves a method call + if (a != a) + return a; + // no need to check if b is NaN; > will work correctly + // recall that -0.0 == 0.0, but [+-]0.0 - [+-]0.0 behaves special + if (a == 0 && b == 0) + return a - -b; + return (a > b) ? a : b; + } + + /** + * The trigonometric function sin. The sine of NaN or infinity is + * NaN, and the sine of 0 retains its sign. This is accurate within 1 ulp, + * and is semi-monotonic. + * + * @param a the angle (in radians) + * @return sin(a) + */ + public static native double sin(double a); + + /** + * The trigonometric function cos. The cosine of NaN or infinity is + * NaN. This is accurate within 1 ulp, and is semi-monotonic. + * + * @param a the angle (in radians) + * @return cos(a) + */ + public static native double cos(double a); + + /** + * The trigonometric function tan. The tangent of NaN or infinity + * is NaN, and the tangent of 0 retains its sign. This is accurate within 1 + * ulp, and is semi-monotonic. + * + * @param a the angle (in radians) + * @return tan(a) + */ + public static native double tan(double a); + + /** + * The trigonometric function arcsin. The range of angles returned + * is -pi/2 to pi/2 radians (-90 to 90 degrees). If the argument is NaN or + * its absolute value is beyond 1, the result is NaN; and the arcsine of + * 0 retains its sign. This is accurate within 1 ulp, and is semi-monotonic. + * + * @param a the sin to turn back into an angle + * @return arcsin(a) + */ + public static native double asin(double a); + + /** + * The trigonometric function arccos. The range of angles returned + * is 0 to pi radians (0 to 180 degrees). If the argument is NaN or + * its absolute value is beyond 1, the result is NaN. This is accurate + * within 1 ulp, and is semi-monotonic. + * + * @param a the cos to turn back into an angle + * @return arccos(a) + */ + public static native double acos(double a); + + /** + * The trigonometric function arcsin. The range of angles returned + * is -pi/2 to pi/2 radians (-90 to 90 degrees). If the argument is NaN, the + * result is NaN; and the arctangent of 0 retains its sign. This is accurate + * within 1 ulp, and is semi-monotonic. + * + * @param a the tan to turn back into an angle + * @return arcsin(a) + * @see #atan2(double, double) + */ + public static native double atan(double a); + + /** + * A special version of the trigonometric function arctan, for + * converting rectangular coordinates (x, y) to polar + * (r, theta). This computes the arctangent of x/y in the range + * of -pi to pi radians (-180 to 180 degrees). Special cases:

This is accurate within 2 ulps, and is semi-monotonic. To get r, + * use sqrt(x*x+y*y). + * + * @param y the y position + * @param x the x position + * @return theta in the conversion of (x, y) to (r, theta) + * @see #atan(double) + */ + public static native double atan2(double y, double x); + + /** + * Take ea. The opposite of log(). If the + * argument is NaN, the result is NaN; if the argument is positive infinity, + * the result is positive infinity; and if the argument is negative + * infinity, the result is positive zero. This is accurate within 1 ulp, + * and is semi-monotonic. + * + * @param a the number to raise to the power + * @return the number raised to the power of e + * @see #log(double) + * @see #pow(double, double) + */ + public static native double exp(double a); + + /** + * Take ln(a) (the natural log). The opposite of exp(). If the + * argument is NaN or negative, the result is NaN; if the argument is + * positive infinity, the result is positive infinity; and if the argument + * is either zero, the result is negative infinity. This is accurate within + * 1 ulp, and is semi-monotonic. + * + *

Note that the way to get logb(a) is to do this: + * ln(a) / ln(b). + * + * @param a the number to take the natural log of + * @return the natural log of a + * @see #exp(double) + */ + public static native double log(double a); + + /** + * Take a square root. If the argument is NaN or negative, the result is + * NaN; if the argument is positive infinity, the result is positive + * infinity; and if the result is either zero, the result is the same. + * This is accurate within the limits of doubles. + * + *

For other roots, use pow(a, 1 / rootNumber). + * + * @param a the numeric argument + * @return the square root of the argument + * @see #pow(double, double) + */ + public static native double sqrt(double a); + + /** + * Raise a number to a power. Special cases:

(In the foregoing descriptions, a floating-point value is + * considered to be an integer if and only if it is a fixed point of the + * method {@link #ceil(double)} or, equivalently, a fixed point of the + * method {@link #floor(double)}. A value is a fixed point of a one-argument + * method if and only if the result of applying the method to the value is + * equal to the value.) This is accurate within 1 ulp, and is semi-monotonic. + * + * @param a the number to raise + * @param b the power to raise it to + * @return ab + */ + public static native double pow(double a, double b); + + /** + * Get the IEEE 754 floating point remainder on two numbers. This is the + * value of x - y * n, where n is the closest + * double to x / y (ties go to the even n); for a zero + * remainder, the sign is that of x. If either argument is NaN, + * the first argument is infinite, or the second argument is zero, the result + * is NaN; if x is finite but y is infinite, the result is x. This is + * accurate within the limits of doubles. + * + * @param x the dividend (the top half) + * @param y the divisor (the bottom half) + * @return the IEEE 754-defined floating point remainder of x/y + * @see #rint(double) + */ + public static native double IEEEremainder(double x, double y); + + /** + * Take the nearest integer that is that is greater than or equal to the + * argument. If the argument is NaN, infinite, or zero, the result is the + * same; if the argument is between -1 and 0, the result is negative zero. + * Note that Math.ceil(x) == -Math.floor(-x). + * + * @param a the value to act upon + * @return the nearest integer >= a + */ + public static native double ceil(double a); + + /** + * Take the nearest integer that is that is less than or equal to the + * argument. If the argument is NaN, infinite, or zero, the result is the + * same. Note that Math.ceil(x) == -Math.floor(-x). + * + * @param a the value to act upon + * @return the nearest integer <= a + */ + public static native double floor(double a); + + /** + * Take the nearest integer to the argument. If it is exactly between + * two integers, the even integer is taken. If the argument is NaN, + * infinite, or zero, the result is the same. + * + * @param a the value to act upon + * @return the nearest integer to a + */ + public static native double rint(double a); + + /** + * Take the nearest integer to the argument. This is equivalent to + * (int) Math.floor(a + 0.5f). If the argument is NaN, the result + * is 0; otherwise if the argument is outside the range of int, the result + * will be Integer.MIN_VALUE or Integer.MAX_VALUE, as appropriate. + * + * @param a the argument to round + * @return the nearest integer to the argument + * @see Integer#MIN_VALUE + * @see Integer#MAX_VALUE + */ + public static int round(float a) + { + // this check for NaN, from JLS 15.21.1, saves a method call + if (a != a) + return 0; + return (int) floor(a + 0.5f); + } + + /** + * Take the nearest long to the argument. This is equivalent to + * (long) Math.floor(a + 0.5). If the argument is NaN, the + * result is 0; otherwise if the argument is outside the range of long, the + * result will be Long.MIN_VALUE or Long.MAX_VALUE, as appropriate. + * + * @param a the argument to round + * @return the nearest long to the argument + * @see Long#MIN_VALUE + * @see Long#MAX_VALUE + */ + public static long round(double a) + { + // this check for NaN, from JLS 15.21.1, saves a method call + if (a != a) + return 0; + return (long) floor(a + 0.5d); + } + + /** + * Get a random number. This behaves like Random.nextDouble(), seeded by + * System.currentTimeMillis() when first called. In other words, the number + * is from a pseudorandom sequence, and lies in the range [+0.0, 1.0). + * This random sequence is only used by this method, and is threadsafe, + * although you may want your own random number generator if it is shared + * among threads. + * + * @return a random number + * @see Random#nextDouble() + * @see System#currentTimeMillis() + */ + public static synchronized double random() + { + if (rand == null) + rand = new Random(); + return rand.nextDouble(); + } + + /** + * Convert from degrees to radians. The formula for this is + * radians = degrees * (pi/180); however it is not always exact given the + * limitations of floating point numbers. + * + * @param degrees an angle in degrees + * @return the angle in radians + * @since 1.2 + */ + public static double toRadians(double degrees) + { + return (degrees * PI) / 180; + } + + /** + * Convert from radians to degrees. The formula for this is + * degrees = radians * (180/pi); however it is not always exact given the + * limitations of floating point numbers. + * + * @param rads an angle in radians + * @return the angle in degrees + * @since 1.2 + */ + public static double toDegrees(double rads) + { + return (rads * 180) / PI; + } +} -- cgit v1.2.1