www.pudn.com > tftb2002toolbox.rar > lambdak.m

function y=lambdak(u,k);
%LAMBDAK Evaluate lambda function for Affine Wigner distribution.
%	Y=LAMBDAK(U,K) evaluates the parametrization lambda function
%	involved in the affine smoothed pseudo Bertrand distribution.
%	
%	 LAMBDAK(U,0) = -U/(exp(-U)-1) for K = 0
%	 LAMBDAK(U,1) = exp(1+U exp(-U)/(exp(-U)-1)) for K = 1
%	 LAMBDAK(U,K) = (K (exp(-U)-1)/(exp(-KU)-1))^(1/(K-1)) otherwise
%
%	U : real vector
%	Y : value of LAMBDAD at point(s) U
%
%	See also LAMBDAB, LAMBDAU, LAMBDAD.

%	P. Goncalves, October 95
%	Copyright (c) 1995 Rice University
%
%	------------------- CONFIDENTIAL PROGRAM -------------------- 
%	This program can not be used without the authorization of its
%	author(s). For any comment or bug report, please send e-mail to 
%	f.auger@ieee.org 

if (k~=0) & (k~=1)
  ind = find(u ~= 0) ;
  y = ones(size(u)) ;
  y(ind) = (k*(exp(-u(ind))-1)./(exp(-k*u(ind))-1)).^(1/(k-1)) ;
elseif k==0
  ind = find(u ~= 0) ;
  y = ones(size(u)) ;
  y(ind) = -u(ind)./(exp(-u(ind))-1) ;
elseif k==1
  ind = find(u ~= 0) ;
  y = ones(size(u)) ;
  y(ind) = exp(1+u(ind).*exp(-u(ind))./(exp(-u(ind))-1)) ;
end;