function pdf = logistic_my_pdf ( x, a, b )

%*****************************************************************************80
%
%% logistic_my_pdf() evaluates the Logistic PDF.
%
%  Discussion:
%
%    Had to insert the idiotic "_my" in the name because Octave has a
%    similarly named function in its automatically installed package.
%
%    PDF(X)(A,B) = EXP ( ( A - X ) / B ) /
%      ( B * ( 1 + EXP ( ( A - X ) / B ) )^2 )
%
%    The Logistic PDF is also known as the Sech-Squared PDF.
%
%  Licensing:
%
%    This code is distributed under the MIT license.
%
%  Modified:
%
%    11 August 2022
%
%  Author:
%
%    John Burkardt
%
%  Input:
%
%    real X, the argument of the PDF.
%
%    real A, B, the parameters of the PDF.
%    0.0 < B.
%
%  Output:
%
%    real PDF, the value of the PDF.
%
  pdf = exp ( ( a - x ) / b ) ./ ( b * ( 1.0 + exp ( ( a - x ) / b ) ).^2 );

  return
end
