GAMPR
This function evaluates the gamma probability density function.
Function Return Value
GAMPR — Function value, the value of the probability density function. (Output)
Required Arguments
X — Argument for which the gamma probability density function is to be evaluated. (Input)
A — The shape parameter of the gamma distribution. (Input)
This parameter must be positive.
FORTRAN 90 Interface
Generic: GAMPR (X, A)
Specific: The specific interface names are S_GAMPR and D_GAMPR.
FORTRAN 77 Interface
Single: GAMPR (X, A)
Double: The double precision name is DGAMPR.
Description
The function GAMPR evaluates the gamma probability density function, defined as
Example
In this example, we evaluate the probability function at X = 4.0, A = 5.0.
USE UMACH_INT
USE GAMPR_INT
IMPLICIT NONE
INTEGER NOUT
REAL X, A, PR
CALL UMACH(2, NOUT)
X = 4.0
A = 5.0
PR = GAMPR(X, A)
WRITE (NOUT, 99999) X, A, PR
99999 FORMAT (' GAMPR(', F4.2, ', ', F4.2, ') = ', F6.4)
END
Output
GAMPR(4.00, 5.00) = 0.1954
