BUGS

-- 
-- BUGS
-- 
-- Copyright (C) 2003, 2004, 2005 Stefan Jahn <stefan@lkcc.org>
-- 
-- This 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.
-- 
-- This software 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 package; see the file COPYING.  If not, write to
-- the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
-- Boston, MA 02110-1301, USA.  
--

This file is intended to collect all known bugs (fixed or unfixed) in
this package.  We will consider fixing these sooner or later.  Please
send Qucs bug reports to <qucs-bugs@lists.sourceforge.net>.

Bug:         B0001
From:	     Stefan Jahn <stefan@lkcc.org>
State:       fixed (2004-10-19/stefan)
Date:	     2004-09-01
Description: Parallel coupled microstrip models do not work.  In fact the
	     characteristic impedances for even and odd mode are wrong.
Fix:	     Found the appropriate publication by Kirschning.

Bug:         B0002
From:	     Stefan Jahn <stefan@lkcc.org>
State:       fixed (2005-05-12/stefan)
Date:	     2005-03-01
Description: Depending on the netlist input order it may occur that a DC
	     analysis converges or does not converge (under-determined
	     equation system?).
Fix:	     The example netlists I had for this case are almost
	     rank-deficient MNA matrices.  Thus another, numerically more
	     stable, matrix decomposition algorithm has been implemented:
	     the QR decomposition using Householder transformations.  The
	     solution algorithm can now be chosen.  The new algorithm is
	     now able to solve the test-cases - LU decomposition was not.

Bug:         B0003
From:	     Stefan Jahn <stefan@lkcc.org>
State:       fixed (2005-03-08/stefan)
Date:	     2005-03-01
Description: Noise correlation matrices of microstrip components can't be
	     calculated assuming a simple attenuation because of the
	     transition time effects.
Fix:	     The calculation is performed using Bosma's theorem.

Bug:         B0004
From:	     Stefan Jahn <stefan@lkcc.org>
State:       fixed (2005-03-08/stefan)
Date:	     2005-03-01
Description: AC output resistance of the BJT model is much too high.
Fix:         Use conservative small signal equivalent circuit description
	     instead of the 'NEWSGP' which works nice for DC calculation
	     anyway.

Bug:         B0005
From:	     Stefan Jahn <stefan@lkcc.org>
State:       unfixed
Date:	     2007-12-30
Description: Empty subcircuit definitions in conjunction with duplicate
	     nodes in the nodelist (shorted nodes) cause the simulator
	     to withdraw the netlist.