v4.1:: Added a function to test if a variable is integer.

git-svn-id: https://www.dynare.org/svn/dynare/trunk@2419 ac1d8469-bf42-47a9-8791-bf33cf982152

matlab/isint.m

+function [b,c,d] = isint(a)
+%  This function tests if the input argument is an integer.
+%
+%  INPUT 
+%    a    [double]   m*n matrix.
+%
+%  OUTPUT 
+%    b    [integer]  m*n matrix of 0 and 1. b(i,j)=1 if a(i,j) is an integer.    
+%    c    [integer]  p*1 vector of indices pointing to the integer elements of a.
+%    d    [integer]  q*1 vector of indices pointing to the non integer elements of a.
+%    
+%  SPECIAL REQUIREMENTS
+%    None.
+%    
+%  NOTES 
+%    p+q is equal to the product of m by n.
+    
+% Copyright (C) 2009 Dynare Team
+%
+% This file is part of Dynare.
+%
+% Dynare is free software: you can redistribute it and/or modify
+% it under the terms of the GNU General Public License as published by
+% the Free Software Foundation, either version 3 of the License, or
+% (at your option) any later version.
+%
+% Dynare is distributed in the hope that it will be useful,
+% but WITHOUT ANY WARRANTY; without even the implied warranty of
+% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+% GNU General Public License for more details.
+%
+% You should have received a copy of the GNU General Public License
+% along with Dynare.  If not, see <http://www.gnu.org/licenses/>.
+
+    [m,n] = size(a);
+    b = abs(fix(a)-a)<1e-15;
+    
+    if nargout>1
+        c = find(b==1);
+        d = find(b==0);
+    end
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