com.imsl.math

Class IEEE

java.lang.Object

com.imsl.math.IEEE

public class IEEE
extends Object

Pure Java implementation of the IEEE 754 functions as specified in IEEE Standard for Binary Floating-Point Arithmetic, ANSI/IEEE Standard 754-1985 (IEEE, New York).

This Java code is based on C code in the package fdlibm, which can be obtained from www.netlib.org. The original fdlibm C code contains the following notice.

Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
Developed at SunSoft, a Sun Microsystems, Inc. business. Permission to use, copy, modify, and distribute this software is freely granted, provided that this notice is preserved.

Author:

Sun Microsystems (original C code in fdlibm), John F. Brophy (translated from C to Java)

Method Summary

Modifier and Type	Method and Description
static double	copysign(double x, double y) Returns a value with the magnitude of x and with the sign bit of y.
static boolean	finite(double x) Finite number test on an argument of type double.
static int	ilogb(double x) Return the binary exponent of non-zero x.
static boolean	isNaN(double x) NaN test on an argument of type double.
static double	nextAfter(double x, double y) Returns the next machine floating-point number next to x in the direction toward y.
static double	scalbn(double x, int n) Returns \(x\,2^n\) computed by exponent manipulation rather than by actually performing an exponentiation or a multiplication.
static boolean	unordered(double x, double y) Unordered test on a pair of doubles.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

copysign

public static double copysign(double x,
                              double y)

Returns a value with the magnitude of x and with the sign bit of y. If y is NaN then |x| is returned.

Parameters:

x - a double from which the magnitude will be gleaned

y - a double from which the sign will be gleaned

Returns:

a double value with magnitude x and sign of y

finite

public static boolean finite(double x)

Finite number test on an argument of type double.

Parameters:

x - the double which is to be tested

Returns:

true if x is a finite number, false if x is a NaN or an infinity

isNaN

public static boolean isNaN(double x)

NaN test on an argument of type double.

Parameters:

x - the double which is to be tested

Returns:

true if x is a NaN, false otherwise

unordered

public static boolean unordered(double x,
                                double y)

Unordered test on a pair of doubles. Tests whether either of a pair of doubles is a NaN.

Parameters:

x - a double

y - a double

Returns:

true if either x or y is a NaN, false otherwise

nextAfter

public static double nextAfter(double x,
                               double y)

Returns the next machine floating-point number next to x in the direction toward y.

Parameters:

x - a double

y - a double

Returns:

a double which represents the value which is closest to x in the interval bounded by x and y

scalbn

public static double scalbn(double x,
                            int n)

Returns \(x\,2^n\) computed by exponent manipulation rather than by actually performing an exponentiation or a multiplication.

Parameters:

x - a double

n - an int representing the power to which 2 is raised

Returns:

a double representing \(x\,2^n\).

ilogb

public static int ilogb(double x)

Return the binary exponent of non-zero x.

Parameters:

x - a double

Returns:

an int representing the binary exponent of x. Special cases ilogb(0) = -Integer.MAX_VALUE and \({\rm {ilogb}} (\infty) = {\rm {ilogb}} (-\infty) = {\rm {ilogb}} (NaN) = {\rm {Integer.MAX\_VALUE}}\).

See Also:

Integer.MAX_VALUE