healpix.essentials
Class HealpixUtils

java.lang.Object
  extended by healpix.essentials.HealpixUtils

public class HealpixUtils
extends Object

Collection of utility functions.

Author:
Martin Reinecke
Copyright:
2011 Max-Planck-Society

Constructor Summary
HealpixUtils()
           
 
Method Summary
static boolean approx(double a, double b, double epsilon)
           
static boolean approx(float a, float b, float epsilon)
           
static void check(boolean cond, String errtxt)
          Evaluates cond; if it is false, throws an Exception containing errtxt.
static double cosdist_zphi(double z1, double phi1, double z2, double phi2)
          Computes the cosine of the angular distance between two z, phi positions on the unit sphere.
static double cosdist_zphi(Zphi zp1, Zphi zp2)
          Computes the cosine of the angular distance between two z, phi positions on the unit sphere.
static double fmodulo(double v1, double v2)
          Returns the remainder of the division v1/v2.
static int ilog2(long arg)
          Integer base 2 logarithm.
static int isqrt(long arg)
          Integer square root.
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

HealpixUtils

public HealpixUtils()
Method Detail

check

public static void check(boolean cond,
                         String errtxt)
                  throws Exception
Evaluates cond; if it is false, throws an Exception containing errtxt.

Throws:
Exception

ilog2

public static int ilog2(long arg)
Integer base 2 logarithm.

Parameters:
arg -
Returns:
the largest integer n that fulfills 2^n<=arg.

isqrt

public static int isqrt(long arg)
Integer square root.

Parameters:
arg -
Returns:
the integer n which fulfills n^2<=arg<(n+1)^2

cosdist_zphi

public static double cosdist_zphi(double z1,
                                  double phi1,
                                  double z2,
                                  double phi2)
Computes the cosine of the angular distance between two z, phi positions on the unit sphere.


cosdist_zphi

public static double cosdist_zphi(Zphi zp1,
                                  Zphi zp2)
Computes the cosine of the angular distance between two z, phi positions on the unit sphere.


fmodulo

public static double fmodulo(double v1,
                             double v2)
Returns the remainder of the division v1/v2. The result is non-negative.

Parameters:
v1 - dividend; can be positive or negative
v2 - divisor; must be positive
Returns:
remainder of the division; positive and smaller than v2

approx

public static boolean approx(float a,
                             float b,
                             float epsilon)

approx

public static boolean approx(double a,
                             double b,
                             double epsilon)

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