Magma vs GMP

Torbjorn Granlund tg at
Fri Dec 2 12:37:57 CET 2005

Magma uses GMP, but now they are bragging that they are "faster than
GMP".  Have they stopped using GMP?  No, they have merely improved the
FFT code in GMP.

What they are doing, is taking advantage of the work of the GMP
developers, while refusing to contribute back.  Instead, they are
trying to hurt GMP's reputation by claiming it is inferior to their
bignum code.

It is a little like if somebody puts a brick on top of a building
built by others, and then bragging they've built a bigger building.

Their behaviour is morally rotten, in my opinion.  But I cannot do
anything about their moral.  But I'd like to scrutinize their LGPL

Therefore I'd like to ask the GMP users for help trying to find out if
their improved FFT code is independent work, or if they have started
with GMP code.  If the latter is the case, and they are failing to
inform their users of that they can get sources for that module, they
would be in breach of the LGPL.

My questions to you are:

1. Do you have a recent copy of Magma?
2. Did you get information about that you can get sources for
   parts of it?
3. Have you tried asking them for sources?
4. What did you get?

5. If you didn't get information about that parts of Magma is Free
   Software, could you please check the following for us:

  A. Is the Magma binary linked such that you can relink it with a
     newer version of GMP?  (LPGL requirement.)

  B. Now, assuming they adhere to the LPGL, and if you're in a country
     that doesn't outlaw it, please disassemble Magma to locate their
     FFT code.  Looking for symbols like fft, dft, ntt, transform,
     trans, forward, forw might speed up this work.  Please don't send
     this disassembled code to anyone, but try to evaluate if its
     structure looks similar to the structure of the code in
     mpn/generic/mul_fft.c.  Please inform us about your findings.

You're welcome to contact me privately for discussions about this,
both via email and via phone at +46 8 429 9490.

Please note that I am not assuming Magma is in breach of the LGPL.
But I intend to carefully scrutinize their compliance.

Torbjörn Granlund
GNU project volunteer

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