Re: the current implementation of logm & funm for GSoC

[PhilipNienhuis]

Abd El Rahman Nour wrote
> Hi,
> 
> I’m currently planning to write a proposal to work on the improvement of
> logm, sqrtm, and funm for google summer of code. 
> I have one problem tho, there’s a lack of details about the currently
> existing implementations of these algorithms. 
> 
> For sqrtm(), there’s a reference for a paper (written in 1999) and I’m
> assuming that the current implementation follows the algorithm in that
> paper. 
> There was a more recent paper published (in 2013) by the same
> researcher(s) that contains some improvement on the previous paper, and
> it’s the currently implemented algorithm in MATLAB’s sqrtm() function, as
> stated in the documentation on their website. 
> 
> For logm and funm tho, octave doesn’t mention anything in the
> documentation, but the papers history is the same here (existing old
> paper, with a new and updated paper proposing improvements, written by the
> same person (also the same one that wrote the sqrtm papers)) 
> 
> I’m really excited to work on the project, and I’ve skimmed through both
> the old paper and the new paper for sqrtm 
> And I skimmed through the old logm and the 3 new papers (yes, there are 3,
> but there’s only 1 main paper) and I wanna read them thoroughly, but I
> just don’t know what the current implementation is, and thus idk if those
> new papers are implemented or not (because there was an attempt on this
> same project idea back in 2015, after those papers were published) 
> 
> Please can anyone help clarify. 
> 
> In short, my question is, what paper was followed for the implementation
> of logm & funm ?
> (Note: just giving the name of an algorithm mentioned isn’t enough, old &
> new papers follow the same algorithm with the same name, just with some
> modification for optimization reasons, so saying “The implementation
> utilizes a Padé approximant and the identity” is of no use to me. 
>  

See this thread for some more info:
http://octave.1599824.n4.nabble.com/GSOC-2017-Idea-Improve-logm-sqrtm-funm-td4682267.html

Philip




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