--- /dev/null
+## Copyright (C) 2006,2007,2008,2011 Carlo de Falco
+##
+## 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>
+
+## -*- texinfo -*-
+##
+## @deftypefn{Function File} {[@var{out}] =} tst_daspk @
+## (@var{cirstruct},@var{x},@var{t},@var{tol},@var{maxit},@
+## @var{pltvars},@var{verbosity},@var{daskopts},@var{dae_fun});
+##
+## Perform a transient simulation of the system described by
+## @var{cirstruct} over the time interval @var{t} using @code{daspk}.
+##
+## The initial value for the state vector is computed by solving a
+## steady state problem at @var{t}(1), with starting guess @var{x}.
+##
+## @var{tol} and @var{maxit} are parameters passed to
+## @code{nls_newton_raphson}.
+##
+## The output @var{out} will contain the value of the state vector
+## at each point of @var{t}.
+##
+## Extra options for @code{daspk} can be passed as name/value pairs in
+## the cellarray @var{daskopts}.
+##
+## The optional parameter @var{verbosity} controls the amount of
+## output produced:
+##
+## @itemize @minus
+## @item if verbosity(1) != 0, information on the progress
+## of the algorithm are output at runtime
+## @item if verbosity(2) != 0, the plot of the variables whose names
+## are listed in @var{pltvars} is
+## produced after the computation
+## @end itemize
+##
+## For special purposes one may need to pass modified jacobian and
+## residual functions. This can be done via the cell array of function
+## handles @var{dae_fun}.
+##
+## Such functions should have the same input and output
+## parameter list as the default sub-functions
+## TSTBWEFUNJAC0,TSTBWEFUNRES0, TSTBWEFUNJAC,TSTBWEFUNRES.
+##
+## @seealso{tst_backward_euler,tst_odepkg,tst_theta_method,nls_newton_raphson,daspk}
+##
+## @end deftypefn
+
+function [out] = tst_daspk (outstruct, x, t, tol, maxit, pltvars, verbosity, daspkopts, dae_fun)
+
+ ## FIXME: add input check!
+ if ((nargin < 6) || (nargin > 9))
+ error ("tst_daspk: wrong number of input parameters.");
+ endif
+
+ if (! exist ("verbosity"))
+ verbosity = [0, 0];
+ elseif (length (verbosity) < 2)
+ verbosity(2) = 0;
+ endif
+
+ if (verbosity(1))
+ fprintf (1, "initial value:\n");
+ endif
+
+ daspk_options ("print initial condition info",1);
+ daspk_options ("maximum order",2);
+ daspk_options ("initial step size",t(2)-t(1));
+ daspk_options ("relative tolerance",1e-3);
+
+ if (nargin > 8)
+ for ii = 1:2:length (daspkopts)
+ daspk_options (daspkopts{ii}, daspkopts{ii+1});
+ endfor
+ endif
+
+
+ [A0, B, C] = asm_initialize_system (outstruct, x);
+
+ if (nargin > 9)
+ JAC = @(x) dae_fun{1} (outstruct, x, t(1), B);
+ RES = @(x) dae_fun{2} (outstruct, x, t(1), B, C);
+ [x, ii, resnrm] = nls_newton_raphson (x, RES, JAC, tol, maxit, verbosity);
+ else
+ [out(:,1), ii] = nls_stationary (outstruct, x, tol, maxit);
+ endif
+
+ if (nargin > 9)
+ JAC = @(x) dae_fun{3} (outstruct, x, t(1), B);
+ RES = @(x) dae_fun{4} (outstruct, x, t(1), B, C);
+ else
+ JAC = @(x,xdot,t,c) TSTDASPKFUNJAC (outstruct, x, xdot, A0, B, t, c);
+ RES = @(x,xdot,t) TSTDASPKFUNRES (outstruct, x, xdot, A0, B, C, t);
+ endif
+
+ [out, xdot, istate, msg] = daspk ({RES,JAC}, out(:,1), zeros (size (x)), t);
+
+ out = out.';
+ if (verbosity(2))
+ utl_plot_by_name (t, out, outstruct, pltvars)
+ endif
+
+endfunction
+
+## Jacobian for transient problem
+function lhs = TSTDASPKFUNJAC (outstruct, x, xdot, A0, B, t, c)
+
+ [A1, Jac, res] = asm_build_system (outstruct, x, t);
+ lhs = (c*(A0+A1) + B + Jac);
+
+endfunction
+
+## Residual for transient problem
+function rhs = TSTDASPKFUNRES (outstruct, x, xdot, A0, B, C, t)
+
+ [A1, Jac, res] = asm_build_system (outstruct, x, t);
+ rhs = (A0+A1)*xdot + B*x + C + res;
+
+endfunction
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