ucar.unidata.util
Class SpecialMathFunction

java.lang.Object
  extended by ucar.unidata.util.SpecialMathFunction

public final class SpecialMathFunction
extends Object

This class contains physical constants and special functions not found in the java.lang.Math class. Like the java.lang.Math class this class is final and cannot be subclassed. All physical constants are in cgs units.

NOTE: These special functions do not necessarily use the fastest or most accurate algorithms.

Author:
Leigh Brookshaw

Field Summary
static double AU
          Astronomical Unit (radius of the Earth's orbit).
static double AVOGADRO
          Avogadro Number.
static double BOLTZMAN
          Boltzman Constant.
static double ECHARGE
          Elementary Charge.
static double EMASS
          Electron Mass.
static double GASCONSTANT
          Gas Constant.
static double GRAV
          Gravitational Constant.
static double GRAVACC
          Gravitational Acceleration at the Earths surface.
static double LIGHTSPEED
          Speed of Light in a Vacuum.
static double PLANCK
          Planck constant.
static double PMASS
          Proton Mass.
static double SOLARFLUX
          Solar Flux.
static double SOLARLUM
          Solar Luminosity.
static double SOLARMASS
          Solar Mass.
static double SOLARRADIUS
          Solar Radius.
static double STEFANBOLTZ
          Stefan-Boltzman Constant.
 
Method Summary
static double acosh(double x)
           
static double asinh(double xx)
          Compute the hyperbolic arc sine
static double atanh(double x)
          Compute the hyperbolic arc tangent
static double chisq(double df, double x)
          Returns the area under the left hand tail (from 0 to x) of the Chi square probability density function with v degrees of freedom.
static double chisqc(double df, double x)
          Returns the area under the right hand tail (from x to infinity) of the Chi square probability density function with v degrees of freedom:
static double cosh(double x)
           
static double erf(double x)
           
static double erfc(double a)
           
static double fac(double x)
           
static int fac(int j)
          Compute the factorial of the argument
static double gamma(double x)
           
static double ibeta(double aa, double bb, double xx)
           
static double igam(double a, double x)
           
static double igamc(double a, double x)
           
static double j0(double x)
           
static double j1(double x)
           
static double jn(int n, double x)
           
static double log10(double x)
          Get the log base 10 of a number
static double log2(double x)
          Get the log base 2 of a number
static double normal(double a)
           
static double poisson(int k, double x)
          Returns the sum of the first k terms of the Poisson distribution.
static double poissonc(int k, double x)
          Returns the sum of the terms k+1 to infinity of the Poisson distribution.
static double sinh(double x)
           
static double tanh(double x)
           
static double y0(double x)
           
static double y1(double x)
           
static double yn(int n, double x)
           
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

BOLTZMAN

public static final double BOLTZMAN
Boltzman Constant. Units erg/deg(K)

See Also:
Constant Field Values

ECHARGE

public static final double ECHARGE
Elementary Charge. Units statcoulomb

See Also:
Constant Field Values

EMASS

public static final double EMASS
Electron Mass. Units g

See Also:
Constant Field Values

PMASS

public static final double PMASS
Proton Mass. Units g

See Also:
Constant Field Values

GRAV

public static final double GRAV
Gravitational Constant. Units dyne-cm^2/g^2

See Also:
Constant Field Values

PLANCK

public static final double PLANCK
Planck constant. Units erg-sec

See Also:
Constant Field Values

LIGHTSPEED

public static final double LIGHTSPEED
Speed of Light in a Vacuum. Units cm/sec

See Also:
Constant Field Values

STEFANBOLTZ

public static final double STEFANBOLTZ
Stefan-Boltzman Constant. Units erg/cm^2-sec-deg^4

See Also:
Constant Field Values

AVOGADRO

public static final double AVOGADRO
Avogadro Number. Units 1/mol

See Also:
Constant Field Values

GASCONSTANT

public static final double GASCONSTANT
Gas Constant. Units erg/deg-mol

See Also:
Constant Field Values

GRAVACC

public static final double GRAVACC
Gravitational Acceleration at the Earths surface. Units cm/sec^2

See Also:
Constant Field Values

SOLARMASS

public static final double SOLARMASS
Solar Mass. Units g

See Also:
Constant Field Values

SOLARRADIUS

public static final double SOLARRADIUS
Solar Radius. Units cm

See Also:
Constant Field Values

SOLARLUM

public static final double SOLARLUM
Solar Luminosity. Units erg/sec

See Also:
Constant Field Values

SOLARFLUX

public static final double SOLARFLUX
Solar Flux. Units erg/cm^2-sec

See Also:
Constant Field Values

AU

public static final double AU
Astronomical Unit (radius of the Earth's orbit). Units cm

See Also:
Constant Field Values
Method Detail

log10

public static double log10(double x)
                    throws ArithmeticException
Get the log base 10 of a number

Parameters:
x - a double value
Returns:
The log10 of x
Throws:
ArithmeticException - if (x < 0)

log2

public static double log2(double x)
                   throws ArithmeticException
Get the log base 2 of a number

Parameters:
x - a double value
Returns:
The log2 of x
Throws:
ArithmeticException - if (x < 0)

cosh

public static double cosh(double x)
                   throws ArithmeticException
Parameters:
x - a double value
Returns:
the hyperbolic cosine of the argument
Throws:
ArithmeticException

sinh

public static double sinh(double x)
                   throws ArithmeticException
Parameters:
x - a double value
Returns:
the hyperbolic sine of the argument
Throws:
ArithmeticException

tanh

public static double tanh(double x)
                   throws ArithmeticException
Parameters:
x - a double value
Returns:
the hyperbolic tangent of the argument
Throws:
ArithmeticException

acosh

public static double acosh(double x)
                    throws ArithmeticException
Parameters:
x - a double value
Returns:
the hyperbolic arc cosine of the argument
Throws:
ArithmeticException

asinh

public static double asinh(double xx)
                    throws ArithmeticException
Compute the hyperbolic arc sine

Parameters:
xx - a double value
Returns:
the hyperbolic arc sine of the argument
Throws:
ArithmeticException

atanh

public static double atanh(double x)
                    throws ArithmeticException
Compute the hyperbolic arc tangent

Parameters:
x - a double value
Returns:
the hyperbolic arc tangent of the argument
Throws:
ArithmeticException

j0

public static double j0(double x)
                 throws ArithmeticException
Parameters:
x - a double value
Returns:
the Bessel function of order 0 of the argument.
Throws:
ArithmeticException

j1

public static double j1(double x)
                 throws ArithmeticException
Parameters:
x - a double value
Returns:
the Bessel function of order 1 of the argument.
Throws:
ArithmeticException

jn

public static double jn(int n,
                        double x)
                 throws ArithmeticException
Parameters:
n - integer order
x - a double value
Returns:
the Bessel function of order n of the argument.
Throws:
ArithmeticException

y0

public static double y0(double x)
                 throws ArithmeticException
Parameters:
x - a double value
Returns:
the Bessel function of the second kind, of order 0 of the argument.
Throws:
ArithmeticException

y1

public static double y1(double x)
                 throws ArithmeticException
Parameters:
x - a double value
Returns:
the Bessel function of the second kind, of order 1 of the argument.
Throws:
ArithmeticException

yn

public static double yn(int n,
                        double x)
                 throws ArithmeticException
Parameters:
n - integer order
x - a double value
Returns:
the Bessel function of the second kind, of order n of the argument.
Throws:
ArithmeticException

fac

public static double fac(double x)
                  throws ArithmeticException
Parameters:
x - a double value
Returns:
the factorial of the argument
Throws:
ArithmeticException

fac

public static int fac(int j)
               throws ArithmeticException
Compute the factorial of the argument

Parameters:
j - an integer value
Returns:
the factorial of the argument
Throws:
ArithmeticException

gamma

public static double gamma(double x)
                    throws ArithmeticException
Parameters:
x - a double value
Returns:
the Gamma function of the value.

Converted to Java from
Cephes Math Library Release 2.2: July, 1992
Copyright 1984, 1987, 1989, 1992 by Stephen L. Moshier
Direct inquiries to 30 Frost Street, Cambridge, MA 02140

Throws:
ArithmeticException

igamc

public static double igamc(double a,
                           double x)
                    throws ArithmeticException
Parameters:
a - double value
x - double value
Returns:
the Complemented Incomplete Gamma function.

Converted to Java from
Cephes Math Library Release 2.2: July, 1992
Copyright 1984, 1987, 1989, 1992 by Stephen L. Moshier
Direct inquiries to 30 Frost Street, Cambridge, MA 02140

Throws:
ArithmeticException

igam

public static double igam(double a,
                          double x)
                   throws ArithmeticException
Parameters:
a - double value
x - double value
Returns:
the Incomplete Gamma function.

Converted to Java from
Cephes Math Library Release 2.2: July, 1992
Copyright 1984, 1987, 1989, 1992 by Stephen L. Moshier
Direct inquiries to 30 Frost Street, Cambridge, MA 02140

Throws:
ArithmeticException

chisq

public static double chisq(double df,
                           double x)
                    throws ArithmeticException
Returns the area under the left hand tail (from 0 to x) of the Chi square probability density function with v degrees of freedom.

Parameters:
df - degrees of freedom
x - double value
Returns:
the Chi-Square function.
Throws:
ArithmeticException

chisqc

public static double chisqc(double df,
                            double x)
                     throws ArithmeticException
Returns the area under the right hand tail (from x to infinity) of the Chi square probability density function with v degrees of freedom:

Parameters:
df - degrees of freedom
x - double value
Returns:
the Chi-Square function.

Throws:
ArithmeticException

poisson

public static double poisson(int k,
                             double x)
                      throws ArithmeticException
Returns the sum of the first k terms of the Poisson distribution.

Parameters:
k - number of terms
x - double value
Returns:
_more_
Throws:
ArithmeticException

poissonc

public static double poissonc(int k,
                              double x)
                       throws ArithmeticException
Returns the sum of the terms k+1 to infinity of the Poisson distribution.

Parameters:
k - start
x - double value
Returns:
_more_
Throws:
ArithmeticException

normal

public static double normal(double a)
                     throws ArithmeticException
Parameters:
a - double value
Returns:
The area under the Gaussian probability density function, integrated from minus infinity to x:
Throws:
ArithmeticException

erfc

public static double erfc(double a)
                   throws ArithmeticException
Parameters:
a - double value
Returns:
The complementary Error function

Converted to Java from
Cephes Math Library Release 2.2: July, 1992
Copyright 1984, 1987, 1989, 1992 by Stephen L. Moshier
Direct inquiries to 30 Frost Street, Cambridge, MA 02140

Throws:
ArithmeticException

erf

public static double erf(double x)
                  throws ArithmeticException
Parameters:
x - double value
Returns:
The Error function

Converted to Java from
Cephes Math Library Release 2.2: July, 1992
Copyright 1984, 1987, 1989, 1992 by Stephen L. Moshier
Direct inquiries to 30 Frost Street, Cambridge, MA 02140

Throws:
ArithmeticException

ibeta

public static double ibeta(double aa,
                           double bb,
                           double xx)
                    throws ArithmeticException
Parameters:
aa - double value
bb - double value
xx - double value
Returns:
The Incomplete Beta Function evaluated from zero to xx.

Converted to Java from
Cephes Math Library Release 2.3: July, 1995
Copyright 1984, 1995 by Stephen L. Moshier
Direct inquiries to 30 Frost Street, Cambridge, MA 02140

Throws:
ArithmeticException


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