﻿Supra 30.0

© 2010-2026 Pedro Mourão Soares Correia

Supra is a chess engine registered with the U.S. Copyright Office (version 17.0) in the name of Pedro Mourão Soares Correia (copyright valid internationally) and distributed under the GNU GPL license (version 3), which allows everyone a versatile use, provided that this use follows the terms of the same license, which is itself based on copyright law. Please see the following FAQs (GNU and OSI).

Acknowledgement:
The multiprocessing (Lazy SMP), the quiescence search, the mop-up, the hash table, the text opening book and the extension to 40 search levels of Supra 30.0 were implemented with the help of Claude, an artificial intelligence by Anthropic. [optional line]

Important note:

Although the GPL is a very versatile license for the users of the program, the copyright is always safeguarded, as these questions and answers from the FAQs make clear:

(Open Source FAQ)

Can I strip out the copyrights on Open Source code and put in my own?

Definitely not! This is not even about Open Source, really: in general, you should not remove a valid copyright notice, no matter what the license specifies. Copyright notices are statutory notices; they are also a source of information about the provenance of source code, and if that information is stripped out, downstream recipients of copies have no easy way to rediscover it.

(GNU Project FAQ)

I want to get credit for my work. I want people to know what I wrote. Can I still get credit if I use the GPL? (#IWantCredit)

You can certainly get credit for the work. Part of releasing a program under the GPL is writing a copyright notice in your own name (assuming you are the copyright holder). The GPL requires all copies to carry an appropriate copyright notice.

My note:

When you change the code of Supra, or of another derivative, you automatically become the author of that change to the original code or derivative. But that does not give you the right to ignore the origin of the original code you used to make your change.

In my opinion, the following changes are not enough to claim copyright:

· Changing variable names.

· Changing function names or prototypes.

· Changing internal parameters (such as the piece values), because these parameters can already be changed in the program's control panel through the GUI. (Of course, adding new parameters is a real change, even if a small one.)

In my opinion, a code change that gives copyright must go beyond simply renaming variables or functions and/or changing internal settings (such as the piece values): it must include a change, however small, to the algorithms or to the internal processes of the program.

So, if you change the code, please add a new line to the copyright information without deleting the previous ones.

See the example in the Stockfish code:

/*
  Stockfish, a UCI chess playing engine derived from Glaurung 2.1
  Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
  Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad

  Stockfish 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 3 of the License, or
  (at your option) any later version.

  Stockfish 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. If not, see <http://www.gnu.org/licenses/>.
*/
