UNDPR

This function evaluates the discrete uniform probability density function.

Function Return Value

UNDPR — Function value, the probability that a random variable from a uniform distribution having scale parameter N will be equal to IX. (Output)

Required Arguments

IX — Argument for which the discrete uniform probability density function is to be evaluated. (Input)

N — Scale parameter. N must be greater than 0. (Input)

FORTRAN 90 Interface

Generic: UNDPR (IX, N)

Specific: The specific interface names are S_UNDPR and D_UNDPR.

FORTRAN 77 Interface

Single: UNDPR (IX, N)

Double: The double precision name is DUNDPR.

Description

The discrete uniform PDF is defined for positive integers x in the range 1, …, N, N > 0. It has the value , and y = 0, for x > N. Allowing the function to accept values of x resulting in y = 0, for x > N is provided as a convenience to the user. Values of x ≤ 0 are errors.

Example

In this example, we evaluate the discrete uniform probability density function at IX = 3, N = 5.

 

USE UMACH_INT

USE UNDPR_INT

IMPLICIT NONE

INTEGER NOUT, IX, N

REAL PR

CALL UMACH(2, NOUT)

IX = 3

N = 5

PR = UNDPR(IX, N)

WRITE (NOUT, 99999) IX, N, PR

99999 FORMAT (' UNDPR(', I2, ', ', I2, ') = ', F6.4)

END

Output

 

UNDPR( 3, 5) = 0.2000