This function evaluates the lognormal probability density function.
Function Return Value
ALNPR — Function value, the value of the probability density function. (Output)
Required Arguments
X — Argument for which the lognormal probability density function is to be evaluated. (Input)
AMU — Location parameter of the lognormal probability function. (Input)
SIGMA — Shape
parameter of the lognormal probability function. SIGMA must be greater
than 0. (Input)
FORTRAN 90 Interface
Generic: ALNPR (X, AMU, SIGMA)
Specific: The specific interface names are S_ALNPR and D_ALNPR.
FORTRAN 77 Interface
Single: ALNPR (X, AMU, SIGMA)
Double: The double precision name is DLNPR.
Description
The function ALNPR evaluates the lognormal probability density function, defined as
.
Example
In this example, we evaluate the probability function at X = 1.0, AMU = 0.0, SIGMA = 0.5.
USE
UMACH_INT
USE
ALNPR_INT
IMPLICIT NONE
INTEGER NOUT
REAL X, AMU, SIGMA, PR
CALL UMACH(2, NOUT)
X = 1.0
AMU = 0.0
SIGMA = 0.5
PR = ALNPR(X, AMU, SIGMA)
WRITE (NOUT, 99999) X, AMU, SIGMA, PR
99999 FORMAT (' ALNPR(', F6.2, ', ', F4.2, ', ', F4.2, ') = ', F6.4)
END
Output
ALNPR( 1.00, 0.00, 0.50) = 0.7979
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