--- /dev/null
+## Copyright (C) 2006,2007,2008 Carlo de Falco, Culpo Massimiliano
+##
+## This file is part of:
+## OCS - A Circuit Simulator for Octave
+##
+## OCS 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.
+##
+## This program 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 this program (see the file LICENSE); if not,
+## see <http://www.gnu.org/licenses/>.
+##
+## author: Carlo de Falco <cdf _AT_ users.sourceforge.net>
+## author culpo@math.uni-wuppertal.de
+
+## -*- texinfo -*-
+##
+## @deftypefn{Function File} @
+## {[@var{a},@var{b},@var{c}]=}Mcurrentsources(@var{string},@var{parameters},@
+## @var{parameternames},@var{extvar},@var{intvar},@var{t})
+##
+## SBN file implementing models for current sources.
+##
+## @var{string} is used to select among models. Parameters are listed
+## as inner items. Possible models are:
+##
+## @enumerate
+## @item @var{string} = "DC" (Static indipendent current source)
+## @itemize @minus
+## @item I -> Current source value
+## @end itemize
+## @item @var{string} = "VCCS" (Voltage controlled current source)
+## @itemize @minus
+## @item K -> Control parameter
+## @end itemize
+## @item @var{string} = "sinwave" (Sinusoidal indipendent current
+## source)
+## @itemize @minus
+## @item shift -> mean value of sinusoidal input
+## @item Ampl -> amplitude of sinusoidal wave
+## @item f -> frequency of sinusoidal wave
+## @item delay -> delay of sinusoidal wave
+## @end itemize
+## @item @var{string} = "VCPS" (Voltage controlled power source)
+## @itemize @minus
+## @item K -> Control parameter
+## @end itemize
+## @end enumerate
+##
+## See the @cite{IFF file format specifications} for details about
+## the output structures.
+##
+## @seealso{prs_iff,asm_initialize_system,asm_build_system}
+## @end deftypefn
+
+function [a,b,c] = Mcurrentsources (string,parameters,parameternames,extvar,intvar,t)
+
+ switch string
+ ## LCR part
+ case "DC"
+ for ii=1:length(parameternames)
+ eval([parameternames{ii} "=" num2str(parameters(ii)) ";"])
+ endfor
+
+ a = zeros(2);
+ b = a;
+ c = [I -I]';
+ break
+
+ case "VCCS"
+ ## Voltage controlled current source
+ K = 1;
+ for ii=1:length(parameternames)
+ eval([parameternames{ii} "=" num2str(parameters(ii)) ";"])
+ endfor
+
+ a = zeros(4);
+ b = [0 0 K -K;\
+ 0 0 -K K;\
+ 0 0 0 0;\
+ 0 0 0 0];
+ c = zeros(4,1);
+ ## NLC part
+ case "sinwave"
+ for ii=1:length(parameternames)
+ eval([parameternames{ii} "=" num2str(parameters(ii)) ";"])
+ endfor
+
+ I = shift+Ampl * sin(2*pi*(t+delay)*f );
+ a = zeros(2);
+ b = a;
+ c = [I -I]';
+ break
+
+ case "VCPS"
+ ## Voltage controlled power source
+ K = 1;
+ for ii=1:length(parameternames)
+ eval([parameternames{ii} "=" num2str(parameters(ii)) ";"])
+ endfor
+
+ dv = extvar(3) - extvar(4);
+ I = K*(dv^2);
+ dIdv = 2*K*dv;
+
+ a = zeros(4);
+ b = [0 0 dIdv -dIdv;\
+ 0 0 -dIdv dIdv;\
+ 0 0 0 0;\
+ 0 0 0 0];
+ c = [I -I 0 0];
+
+ otherwise
+ error (["unknown section:" string])
+ endswitch
+
+endfunction