--- /dev/null
+function [resu, rcond] = inv(df);
+
+ %# function [x, rcond] = inv(df)
+ %# Overloaded function computing the inverse of a dataframe. To
+ %# succeed, the dataframe must be convertible to an square array. Row
+ %# and column meta-information are exchanged.
+
+ %% Copyright (C) 2009-2012 Pascal Dupuis <Pascal.Dupuis@uclouvain.be>
+ %%
+ %% This file is part of Octave.
+ %%
+ %% Octave 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 2, or (at your option) any later version.
+ %%
+ %% Octave 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 Octave; see the file COPYING. If not,
+ %% write to the Free Software Foundation, 51 Franklin Street -
+ %% Fifth Floor, Boston, MA 02110-1301, USA.
+
+ %#
+ %# $Id: inv.m 9585 2012-02-05 15:32:46Z cdemills $
+ %#
+
+ if (length(df._cnt) > 2 || (df._cnt(1) != df._cnt(2))),
+ error("Dataframe is not square");
+ endif
+
+ %# quick and dirty conversion
+ [dummy, rcond] = inv(horzcat(df._data{:}));
+
+ resu = df_allmeta(df);
+
+ [resu._name{2}, resu._name{1}] = deal(resu._name{1}, resu._name{2});
+ [resu._over{2}, resu._over{1}] = deal(resu._over{1}, resu._over{2});
+ if (isempty(resu._name{2})),
+ resu._name{2} = cellstr(repmat('_', resu._cnt(2), 1));
+ resu._over{2} = ones(1, resu._cnt(2));
+ endif
+ for indi = resu._cnt(1):-1:1,
+ resu._data{indi} = dummy(:, indi);
+ endfor
+ resu._type(:) = class(dummy);
+
+endfunction