Re: Improving sqrtm

[Nicholas Jankowski]

On Tue, Feb 16, 2016 at 11:45 AM, Mudit Sharma <address@hidden> wrote:

Indeed that would be against the spirit of open-source.

I provided the sqrtm link so as to make it some informative for the readers/maintainers.

Infact the improved sqrtm will be based on Higham's latest work on sqrtm which

dates back to 1999 (www.maths.manchester.ac.uk/~higham/narep/narep336.ps.gz)
and Matlab still uses work previous than the latest algorithm proposed in 1999.

Higham's work on sqrtm in 1999 will be the basis for the improved sqrtm  and not on Matlab's

work.

Bests,

Mudit

On Tue, Feb 16, 2016 at 9:31 PM, John W. Eaton <address@hidden> wrote:

On 02/16/2016 03:10 AM, Mudit Sharma wrote:

All,
I'm improving sqrtm in Octave and want to align it with
the sqrtm from Matlab which has 3 output arguments,
whereas the existing sqrtm.cc from octave has 2 .

Here's the link for sqrtm from Matlab:
https://github.com/RickOne16/sqrtm/blob/master/sqrtm.m

and this is octave's sqrtm:
https://github.com/RickOne16/sqrtm/blob/master/sqrtm.cc

How do I change the octave's sqrtm code to align it with that
from Matlab which has 3 output arguments?

One thing you can't do is use the code you've linked to as a basis for your changes.  That code clearly has a MathWorks copyright notice on it.  So now I'm not likely to accept any changes from you related to this function.

If you want to contribute to the development of Octave it is critical that the work you do is your own, or that it is based on free software.

jwe

Generally speaking, we should be able to pull most necessary information from public-facing help files, Matlab's public documentation, or user reports of behavior. The concern is copyright. Math is public domain. Software algorithms can be copyrighted. Copyright involves legal concerns. Even using copyrighted code as a reference before writing your own can be problematic. John's concern is valid, as he has to maintain integrity of the codebase.

Nick J.