function yr = trank(y);
% yr = trank(y);
% yr is the rank transformation of y
%
% Part of the Sensitivity Analysis Toolbox for DYNARE
%
% Written by Marco Ratto, 2006
% Joint Research Centre, The European Commission,
% (http://eemc.jrc.ec.europa.eu/),
% marco.ratto@jrc.it 
%
% Disclaimer: This software is not subject to copyright protection and is in the public domain. 
% It is an experimental system. The Joint Research Centre of European Commission 
% assumes no responsibility whatsoever for its use by other parties
% and makes no guarantees, expressed or implied, about its quality, reliability, or any other
% characteristic. We would appreciate acknowledgement if the software is used.
% Reference:
% M. Ratto, Global Sensitivity Analysis for Macroeconomic models, MIMEO, 2006.
%

[nr, nc] = size(y);
for j=1:nc,
  [dum, is]=sort(y(:,j));
  yr(is,j)=[1:nr]'./nr;
end