---

C Library Functions  - logsf (3)

---

NAME

logsf(3f) - [M_datapac:SPARSITY] compute the logistic sparsity function

CONTENTS

Synopsis
Description
Input Arguments
Output Arguments
Examples
Author
Maintainer
License
References

SYNOPSIS

SUBROUTINE LOGSF(P,Sf)

       REAL(kind=wp),intent(in)  :: P
       REAL(kind=wp),intent(out) :: Sf

DESCRIPTION

LOGSF(3f) computes the sparsity function value for 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))

Note that the sparsity function of a distribution is the derivative of the percent point function, and also is the reciprocal of the probability density function (but in units of P rather than X).

INPUT ARGUMENTS

P	The value at which the sparsity function is to be evaluated. P should be between 0.0 and 1.0, exclusively.

OUTPUT ARGUMENTS

SF	The sparsity function value.

EXAMPLES

Sample program:

   program demo_logsf
   use M_datapac, only : logsf
   implicit none
   ! call logsf(x,y)
   end program demo_logsf

Results:

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o	Filliben, Simple and Robust Linear Estimation of the Location Parameter of a Symmetric Distribution (Unpublished PH.D. Dissertation, Princeton University), 1969, pages 21-44, 229-231.
o	Filliben, ’The Percent Point Function’, (Unpublished Manuscript), 1970, pages 28-31.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

logsf (3)

July 22, 2023

Generated by manServer 1.08 from a0dcdd02-4c01-49a3-8004-05aede2ebf1b using man macros.