Added a routine to test if an array is a square matrix.

matlab/issquare.m

+function i = issquare(A)
+
+%@info:
+%! @deftypefn {Function File} {@var{i} =} issquare (@var{A})
+%! @anchor{issquare}
+%! @sp 1
+%! Returns 1 if @var{A} is a square matrix, 0 otherwise.
+%! @sp 2
+%! @strong{Inputs}
+%! @sp 1
+%! @table @ @var
+%! @item A
+%! Matrix.
+%! @end table
+%! @sp 1
+%! @strong{Outputs}
+%! @sp 1
+%! @table @ @var
+%! @item i
+%! Integer scalar (0 or 1).
+%! @end table
+%! @sp 2
+%! @strong{This function is called by:}
+%! @sp 2
+%! @strong{This function calls:}
+%! @sp 2
+%! @end deftypefn
+%@eod:
+
+% Copyright (C) 2012 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/>.
+
+d = size(A);
+i = (length(d)==2) && (d(1)==d(2));
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