healpix.core.base
Class BitManipulation

java.lang.Object
  healpix.core.base.BitManipulation

public class BitManipulation
extends Object

This module provides functions that permute bits of the binary representation of a number. Java bit manipulation class derived from Healpix fortran90 program.

Version:

$Id: BitManipulation.java,v 1.1.2.4 2010/02/22 14:55:50 healpix Exp $

Author:

Benjamin D. Wandelt October 1997, edited by E. Hivon, October 2001 to be 'F' compatible

magic1

public static long magic1

The magic1.

magic2

public static long magic2

The magic2.

BitManipulation

public BitManipulation()

default constructor

swapLSBMSB

public long swapLSBMSB(long i)

swaps low and high bits in the word i

Parameters:

i - integer input word

Returns:

int a word with odd and even bits interchanged

invswapLSBMSB

public long invswapLSBMSB(long i)

returns NOT i with even and odd bit positions interchanged

Parameters:

i - int input word

Returns:

int NOT (i with LSBMSB)

invLSB

public long invLSB(long i)

returns i with even bits (0,2,4,...) inverted

Parameters:

i - int input word

Returns:

int word with modified bits

invMSB

public long invMSB(long i)

returns i with odd bits (1,3,5,...) inverted

Parameters:

i - int input word

Returns:

int word with modified bits

MODULO

public double MODULO(double a,
                     double b)

simulates behaviour of fortran90 MODULO function

Parameters:

a - double

b - double

Returns:

double MODULO