On 7/22/06, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
Hello,

Following this week discussion about copyright issues in math code, I think two
more Mantissa classes should not be included as is to commons-math code. I
really did write them myself but took inspiration from existing code, not only
texbooks. The first class is the Gragg-Bulirsch-Stoer integrator which was
inspired from an implementation by Hairer and Wanner. The second class is the
highest level part of the Levenberg-Marquardt implementation which was inspired
from NETLIB code (is this acceptable for commons-math ?).

If it is translation of code, vs. independent implementation of the
same algorithm, we should avoid that, unless the implementation is
licensed under an ASL-compatible license or we get the authors to
agree to relicense it.  NETLIB does not appear to have a standard
license, so this would have to be researched for the individual
modules that you drew your implementation from.  Clean room
implementations of the algorithms directly are preferred, but if you
are willing to do the legwork to research the license terms of the
NETLIB code and/or get the necessary permission from the authors, we
can use the "inspired" code, including appropriate attributions.

The lowest level part,
on the other hand, which is the QR decomposition with columns reordering, is an
orginal implementation following a french textbook from the 80's.

For these two classes, I will see if I can provide completely original
implementations. I hope no other classes present the same problem, I will check
each one.

sorry for the inconvenience

No problem and thanks for the dilligence on this.

Phil

Luc

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