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Ngspice-21 Documentation
Copyright (c) 2010, Paolo Nenzi, Holger Vogt
All rights reserved.


Foreword:
Spice's name was originally chosen at the University of California, Berkeley. 
As it is the basis of almost all circuit simulators, the major part of the 
analogue and mixed signals simulation's code is designed to fit with it. 
The *spices (generic name for its forks) are heterogeneous in many points due
to the work of researchers, electronic designers, software editors, etc.
The Ngspice team tries to collect work from the different sources and 
contribute new functionalities. Thus, the material we manipulate is 
heterogeneous in licenses. Keeping the licenses as is, is the way to live with
that diversity. For release 21 as well, we choose not to relicense.

Copyleft is a fundamental question in FOSS development. The choice of a 
copylefted contribution, or a non copylefted contribution is an important
choice that should be respected. Ngspice branch as a whole will not be covered
by a specific license. The Ngspice team wants to encourage contributions to 
ngspice. We let each new developper choose its position regarding copyleft, 
as we respect the position of the former developpers. In order to keep things 
clear ngspice team proposes to follow the following guidelines:

  Each piece of code should be kept under its original contributor's license. 
  As for any project, modifications made in sources covered by a less
  restrictive license can be covered by a more restrictive license, such as 
  GPL. We do not encourage it.

  If you feel to add code in a file under a different license than the rest of
  the file, please use comments to mark the boundaries of the modification, and
  edit the comments at the begining of the file with correct license and 
  copyright information.

  We encourage restrictive licenses to be chosen only for new functionalities, 
  written in distinct files, leading to distinct libraries that links depending 
  on a specific configure flag.

  We encourage non proliferation of licenses (e.g. choosing either GPL, LGPL or
  new BSD). 

This heterogenous license status makes it difficult to know which license 
applies. Please take care of knowing which license aplies to the code you are 
editing, or conveying and not to commit license infringements, especially to 
GPL and LGPL which are quite restrictive.

On 2007, July 17th spice 3f5 changed from its original license to the new BSD 
license. (http://embedded.eecs.berkeley.edu/pubs/downloads/spice/index.htm)

On 2008, December 1st, tclspice changes license from GPL to LGPLv2, in 
accordance with Multigig Ltd, the copyright holder.

The following table is just a reminder on license status, please don't rely
on it: 
          Author            License  Notes		
			
numparam  Georg Post        LGPL     Applies to the code in 
                                     frontend/numparam		
adms      Laurent Lemaitre  LGPL     Applies to scripts in the 
                                     spicelib/dev/adms
tclspice  Stefan Jones 	    LGPL     TCL integration 
cider     U. of California  Old BSD  Device level simulator
xspice    Georgia Tech.     Public D Mixed signals   
spice     U. of California  New BSD  Analog circuit simulation
			
 
---------------------------------- Cider -----------------------------------
  
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---------------------------------- Spice3f5 -------------------------------- 

Copyright (c) 1985-1991 The Regents of the University of California.
All rights reserved.

Permission is hereby granted, without written agreement and without license
or royalty fees, to use, copy, modify, and distribute this software and its
documentation for any purpose, provided that the above copyright notice and
the following two paragraphs appear in all copies of this software.

IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR
DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT
OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF
CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN
"AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATION TO PROVIDE
MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.


---------------------------------- XSPICE -------------------------------- 

XSPICE SOFTWARE USER'S MANUAL copyright

Copyright  1992 Georgia Tech Research Corporation All Rights Reserved. 
This material may be reproduced by or for the U.S. Government pursuant 
to the copyright license under the clause at DFARS 252.227-7013 (Oct. 1988)
