NOTICE — Third-Party Copyrights and Licenses
=============================================

neospice is licensed under the MIT License (see LICENSE). However, portions of
the core simulation engine in src/core/ and the device model code in
src/devices/ are derived from or translated from third-party sources that
retain their own copyright notices and license terms. These are documented
below.


1. University of California, Berkeley — SPICE3 / SPICE2 — Core Engine
---------------------------------------------------------------------

Portions of the core simulation engine in src/core/ are translated from UC
Berkeley SPICE3F5 and derive from the earlier SPICE2G6 (1983) Fortran and the
original SPICE / SPICE2 work. This includes the DC operating point, DC sweep,
transient analysis (the MODE / INITF state machine and LTE timestep control),
AC analysis, noise analysis, transfer function, pole-zero, sensitivity, and the
Newton-Raphson convergence aids (e.g. derived from dctran.c, niiter.c, and the
MODE bit definitions in cktdefs.h).

The behavioral-source DDT history and zero-Jacobian behavior in
src/devices/asrc/expression_ast.cpp follow ngspice's parser/PTddt and PTF_DDT
implementation (ptfuncs.c and inpptree.c). The original parse-tree functions
are attributed to Wayne A. Christopher, U. C. Berkeley CAD Group (1987),
and maintained by the ngspice contributors.

  Copyright 1990 Regents of the University of California.
  All rights reserved.

  Distributed under the permissive BSD-style "Berkeley Spice3" license.

ngspice (maintained SPICE3F5 descendant):

  The maintained SPICE3F5 descendant ngspice is used as the reference
  implementation for neospice. Credit to Paolo Nenzi, Holger Vogt,
  Dietmar Warning, and the ngspice maintainers.

Historical references:

  L. W. Nagel and D. O. Pederson, "SPICE," Memorandum No. ERL-M382,
  UC Berkeley, April 1973.

  L. W. Nagel, "SPICE2: A Computer Program to Simulate Semiconductor
  Circuits," Memorandum No. ERL-M520, UC Berkeley, May 1975.

  SPICE2G6 (1983) and SPICE3F5 (UC Berkeley).


2. Sparse Solver Stack — Sparse 1.3, SuiteSparse AMD / BTF
-----------------------------------------------------------

The sparse solver stack (src/core/neo_solver.cpp, amd.cpp, btf.cpp,
matching.cpp) traces to the following sources.

  The NeoSolver sparse-LU factorization is "Sparse 1.3-compatible." Credit to
  Kenneth S. Kundert and Alberto Sangiovanni-Vincentelli, "Sparse 1.3"
  (UC Berkeley), the sparse-matrix package used by SPICE3.

  The ordering in amd.cpp performs minimum-degree elimination on an explicit
  graph. Its dense-vertex threshold follows the default SuiteSparse AMD
  heuristic. Preserve credit to Timothy A. Davis, Patrick Amestoy, and Iain
  Duff (SuiteSparse AMD, BSD-3-Clause). The implementation does not reproduce
  AMD's quotient-graph algorithm or promise an identical permutation.

  The BTF / maximum-transversal logic in btf.cpp and matching.cpp likewise
  traces to Timothy A. Davis's SuiteSparse BTF (BSD-3-Clause licensed).


3. University of California, Berkeley — SPICE3 / BSIM
------------------------------------------------------

The following device models contain code derived from UC Berkeley's SPICE3
simulator and BSIM compact model implementations. Original copyright notices
are preserved in each source file.

  Copyright 1990-2010 Regents of the University of California.
  All rights reserved.

  Devices: bjt, dio, jfet, ltra, mes, mos1, mos3, mos9, vbic,
           bsim3 (v3.3.0), bsim3v32 (v3.2.4), bsim4v7 (v4.7.0), bsimsoi

  Authors include: Thomas L. Quarles, Min-Chie Jeng, Weidong Liu,
  Xuemei Xi, Mansun Chan, Mohan Dunga, Ali Niknejad, Chenming Hu,
  Wenwei Yang, Darsen Lu, Samuel Fung, Dennis Sinitsky, Stephen Tang,
  Pin Su, Hui Wan, Wei Jin, Chung-Hsun Lin, Tanvir Morshed,
  Jaijeet S. Roychowdhury.

  The BSIM4 model is subject to additional terms of use from the
  UC Berkeley BSIM Research Group (see below).

BSIM4 Terms of Use (UC Berkeley BSIM Research Group):

  Software is distributed as is, completely without warranty or service
  support. The University of California and its employees are not liable
  for the condition or performance of the software.

  The University of California grants the users the right to modify, copy,
  and redistribute the software and documentation, subject to the following
  restrictions:

  1. The users agree not to charge for the University of California code
     itself but may charge for additions, extensions, or support.

  2. In any product based on the software, the users agree to acknowledge
     the UC Berkeley BSIM Research Group that developed the software. This
     acknowledgment shall appear in the product documentation.

  3. The users agree to obey all U.S. Government restrictions governing
     redistribution or export of the software.

  4. The users agree to reproduce any copyright notice which appears on
     the software on any copy or modification of such made available
     to others.


4. Sydney University — JFET Modifications
------------------------------------------

  Copyright (c) 1989 Anthony E. Parker, David J. Skellern
  Laboratory for Communication Science Engineering
  Sydney University Department of Electrical Engineering, Australia

  Device: jfet (modifications to the UC Berkeley JFET model)


5. Macquarie University — Parker-Skellern JFET2 Model
------------------------------------------------------

  Copyright 1994 Macquarie University, Sydney Australia.
  Author: Anthony E. Parker

  Device: jfet2 (PS model additions to the UC Berkeley JFET model)


6. Hiroshima University & STARC — HiSIM2
-----------------------------------------

  HiSIM (Hiroshima University STARC IGFET Model)
  Copyright (C) 2012 Hiroshima University &
  Semiconductor Technology Academic Research Center (STARC)

  MODEL NAME: HiSIM (VERSION 2, SUBVERSION 7, REVISION 0)
  Device: hisim2

  Software is distributed as is, completely without warranty or service
  support. Hiroshima University and STARC own the copyright and grant users
  a perpetual, irrevocable, worldwide, non-exclusive, royalty-free license
  with respect to the software, subject to the following restrictions:

  1. The users agree not to charge for Hiroshima University and STARC code
     itself but may charge for additions, extensions, or support.

  2. In any product based on the software, the users agree to acknowledge
     Hiroshima University and STARC that developed the software. This
     acknowledgment shall appear in the product documentation.

  3. The users agree to reproduce any copyright notice which appears on the
     software on any copy or modification of such made available to others.


7. Hiroshima University & STARC — HiSIM_HV
-------------------------------------------

  HiSIM (Hiroshima University STARC IGFET Model)
  Copyright (C) 2014 Hiroshima University &
  Semiconductor Technology Academic Research Center (STARC)

  MODEL NAME: HiSIM_HV (VERSION 2, SUBVERSION 2, REVISION 0)
  Device: hisimhv

  The source code and all copyrights, trade secrets or other intellectual
  property rights are owned by Hiroshima University and STARC. License terms
  are identical to HiSIM2 above.

  Signed: Toshimasa Asahara, Mitiko Miura-Mattausch (Hiroshima University),
  Katsuhiro Shimohigashi (STARC) — June 2008, revised October 2011.


8. MacSpice3f4 — HFET Models
-----------------------------

  Imported from MacSpice3f4 — Antony Wilson
  Modified: Paolo Nenzi

  Devices: hfet1 (Curtice Cubic), hfet2 (Chalmers)


9. VBIC Model — Additional Credits
-----------------------------------

  Model Author: 1995 Colin McAndrew, Motorola
  Spice3 Implementation: 2003 Dietmar Warning, DAnalyse GmbH

  Device: vbic (within the UC Berkeley copyright framework)


10. ngspice Community Contributors
----------------------------------

  Several device models include modifications by:
  - Paolo Nenzi (2002-2003)
  - Dietmar Warning (2003-2012)
  - Alan Gillespie ("AlansFixes", 2000)

  These modifications were made within the UC Berkeley SPICE3 license
  framework.
