RALPR

This function evaluates the Rayleigh probability density function.

Function Return Value

RALPR — Function value, the value of the probability density function. (Output)

Required Arguments

X — Argument for which the Rayleigh probability density function is to be evaluated. (Input)

ALPHA — Scale parameter of the Rayleigh probability function. (Input)

FORTRAN 90 Interface

Generic: RALPR (X, ALPHA)

Specific: The specific interface names are S_RALPR and D_RALPR.

FORTRAN 77 Interface

Single: RALPR (X, ALPHA)

Double: The double precision name is DRALPR.

Description

The function RALPR evaluates the Rayleigh probability density function, which is a special case of the Weibull probability density function where GAMMA is equal to 2.0, and is defined as

 

Example

In this example, we evaluate the Rayleigh probability density function at X = 0.25, ALPHA = 0.5.

 

USE UMACH_INT

USE RALPR_INT

IMPLICIT NONE

INTEGER NOUT

REAL X, ALPHA, PR

CALL UMACH(2, NOUT)

X = 0.25

ALPHA = 0.5

PR = RALPR(X, ALPHA)

WRITE (NOUT, 99999) X, ALPHA, PR

99999 FORMAT (' RALPR(', F4.2, ', ', F4.2, ') = ', F6.4)

END

Output

 

RALPR(0.25, 0.50) = 0.8825