C Library Functions  - logran (3)

NAME

logran(3f) - [M_datapac:RANDOM] generate logistic random numbers

CONTENTS

Synopsis
Description
Input Arguments
Output Arguments
Examples
Author
Maintainer
License
References

SYNOPSIS

SUBROUTINE LOGRAN(N,Iseed,X)

       INTEGER,intent(in)        :: N
       INTEGER,intent(inout)     :: Iseed
       REAL(kind=wp),intent(out) :: X(:)

DESCRIPTION

LOGRAN(3f) generates a random sample of size N from the logistic distribution with mean = 0 and standard deviation = pi/sqrt(3).

This distribution is defined for all X and has the probability density function

       f(X) = exp(X)/(1+exp(X))

INPUT ARGUMENTS

N The desired integer number of random numbers to be generated.

ISEED An integer seed value. Should be set to a non-negative value to start a new sequence of values. Will be set to -1 on return to indicate the next call should continue the current random sequence walk.

OUTPUT ARGUMENTS

X A vector (of dimension at least N) into which the generated random sample of size N from the logistic distribution will be placed.

EXAMPLES

Sample program:

   program demo_logran
   use m_datapac, only : logran, plott, label, plotxt, sort
   implicit none
   integer,parameter :: n=4000
   integer           :: iseed
   real              :: x(n)
      call label(’logran’)
      iseed=12345
      call logran(N,Iseed,X)
      call plotxt(x,n)
      call sort(x,n,x) ! sort to show distribution
      call plotxt(x,n)
   end program demo_logran

Results:

    THE FOLLOWING IS A PLOT OF X(I) (VERTICALLY) VERSUS I (HORIZONTALLY
                      I-----------I-----------I-----------I-----------I
     0.1011046E+02 -   X
     0.9310020E+01 I
     0.8509579E+01 I                   X
     0.7709137E+01 I                          X
     0.6908696E+01 I                                    X
     0.6108254E+01 I           X      X X          X      X  XXX
     0.5307813E+01 -   X        X X X XX X        X X         X X    X
     0.4507371E+01 I    X X  X      X XXX    XXXX XXX  X X X XX X  X X
     0.3706930E+01 I  XXXXXXXXXXXXX XX XX XXX XXXXXXXXXXXXXXXXX X XXXXX
     0.2906488E+01 I  XXXXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXXXXXXXX
     0.2106047E+01 I  XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
     0.1305605E+01 I  XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
     0.5051632E+00 -  XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
    -0.2952785E+00 I  XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
    -0.1095719E+01 I  XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
    -0.1896161E+01 I  XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
    -0.2696603E+01 I  XXXXXXXXXXXXXXXXXXXXXXXXX XXXX XXXXXXXXXXXXXXXXXX
    -0.3497045E+01 I  XX XXXX XXXXX XXXXXXXX  XX XXXX XXXX XXXXXXXXXXXX
    -0.4297486E+01 -  XXX XXXXXXX XX X XXX  XXX XXXX XXXXX   X X XXXX
    -0.5097927E+01 I       XX X     X X XXX XX X    XXXX       X   XXX
    -0.5898369E+01 I        X          X   X  XX XXX  X          X
    -0.6698811E+01 I               X
    -0.7499252E+01 I                       X
    -0.8299694E+01 I
    -0.9100137E+01 -                                          X
                      I-----------I-----------I-----------I-----------I
               0.1000E+01  0.1001E+04  0.2000E+04  0.3000E+04  0.4000E+04

THE FOLLOWING IS A PLOT OF X(I) (VERTICALLY) VERSUS I (HORIZONTALLY I-----------I-----------I-----------I-----------I 0.1011046E+02 - X 0.9310020E+01 I 0.8509579E+01 I X 0.7709137E+01 I X 0.6908696E+01 I X 0.6108254E+01 I X 0.5307813E+01 - X 0.4507371E+01 I XX 0.3706930E+01 I XX 0.2906488E+01 I XXX 0.2106047E+01 I XXXXX 0.1305605E+01 I XXXXXXXX 0.5051632E+00 - XXXXXXXXX -0.2952785E+00 I XXXXXXXXXX -0.1095719E+01 I XXXXXXXX -0.1896161E+01 I XXXXXX -0.2696603E+01 I XXX -0.3497045E+01 I XX -0.4297486E+01 - XX -0.5097927E+01 I X -0.5898369E+01 I X -0.6698811E+01 I X -0.7499252E+01 I X -0.8299694E+01 I -0.9100137E+01 - X I-----------I-----------I-----------I-----------I 0.1000E+01 0.1001E+04 0.2000E+04 0.3000E+04 0.4000E+04

AUTHOR

The original DATAPAC library was written by James Filliben of the Statistical Engineering Division, National Institute of Standards and Technology.

MAINTAINER

John Urban, 2022.05.31

LICENSE

CC0-1.0

REFERENCES

o Tocher, The Art of Simulation, 1963, pages 14-15.
o Hammersley and Handscomb, Monte Carlo Methods, 1964, page 36.
o Filliben, Simple and Robust Linear Estimation of the Location Parameter of a Symmetric Distribution (Unpublished PH.D. Dissertation, Princeton University), 1969, page 230.
o Filliben, ’The Percent Point Function’, (Unpublished Manuscript), 1970, pages 28-31.
o Johnson and Kotz, Continuous Univariate Distributions--2, 1970, pages 1-21.


Nemo Release 3.1 logran (3) July 22, 2023
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