--- /dev/null
+## Copyright (C) 2009, 2010, 2011 Lukas F. Reichlin
+##
+## This file is part of LTI Syncope.
+##
+## LTI Syncope 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.
+##
+## LTI Syncope 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 LTI Syncope. If not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{sys} =} mconnect (@var{sys}, @var{m})
+## @deftypefnx {Function File} {@var{sys} =} mconnect (@var{sys}, @var{m}, @var{inputs}, @var{outputs})
+## Arbitrary interconnections between the inputs and outputs of an LTI model.
+##
+## @strong{Inputs}
+## @table @var
+## @item sys
+## LTI system.
+## @item m
+## Connection matrix. Each row belongs to an input and each column represents an output.
+## @item inputs
+## Vector of indices of those inputs which are retained. If not specified, all inputs are kept.
+## @item outputs
+## Vector of indices of those outputs which are retained. If not specified, all outputs are kept.
+## @end table
+##
+## @strong{Outputs}
+## @table @var
+## @item sys
+## Interconnected system.
+## @end table
+##
+## @strong{Example}
+## @example
+## @group
+## Solve the system equations of
+## y(t) = G e(t)
+## e(t) = u(t) + M y(t)
+## in order to build
+## y(t) = H u(t)
+## The matrix M for a (p-by-m) system G
+## has m rows and p columns (m-by-p).
+##
+## Example for a 3x2 system:
+## u1 = -1*y1 + 5*y2 + 0*y3
+## u2 = pi*y1 + 0*y2 - 7*y3
+##
+## | -1 5 0 |
+## M = | pi 0 7 |
+## @end group
+## @end example
+## @end deftypefn
+
+## Author: Lukas Reichlin <lukas.reichlin@gmail.com>
+## Created: October 2009
+## Version: 0.2
+
+function sys = mconnect (sys, M, in_idx, out_idx = ":")
+
+ if (nargin < 2 || nargin > 4)
+ print_usage ();
+ endif
+
+ [p, m] = size (sys);
+ [mrows, mcols] = size (M);
+
+ if (p != mcols || m != mrows)
+ error ("mconnect: second argument must be a (%dx%d) matrix", m, p);
+ endif
+
+ if (! is_real_matrix (M))
+ error ("mconnect: second argument must be a matrix with real coefficients");
+ endif
+
+ sys = __sys_connect__ (sys, M);
+
+ if (nargin > 2)
+ sys = __sys_prune__ (sys, out_idx, in_idx);
+ endif
+
+endfunction
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