Re: Status for GSoC project : Improve logm,sqrtm and funm

[Mudit Sharma]

Hi,

The state of the art work done on matrix exponential is by

Prof. N.J. Higham from the U of Manchester. Last year Marco and I

assembled m-file codes for some matrix functions including expm.

Here's the code : https://github.com/RickOne16/matrix/blob/master/expm_new.m

Some work on matrix functions remains after which Octave will be

loaded with the best algorithms on matrix functions.

1) calling external code from oct-files is a part of octave. Sometimes it becomes

    important if there are a large number of loops or other time consuming parts.

    You can visit this for more info :
http://www.gnu.org/software/octave/doc/v4.0.1/Calling-External-Code-from-Oct_002dFiles.html

It says it's a bit difficult with Fortran.

See Also : http://www.gnu.org/software/octave/doc/v4.0.1/External-Code-Interface.html

2) A test example which is a benchmark for expm is this:
http://blogs.mathworks.com/cleve/2012/07/23/a-balancing-act-for-the-matrix-exponential/#7401fe8a-5a7d-40df-92d7-1ae34f45adf2

3) The ease of writing code is the best when done as m-files.

 C/C++ impart speed when the m-files need a large time.

Thus one can utilize octave to it's full potential with C/C++ and M-files.

 Yes, C/C++ and M-files are preferred than Fortran.

Bests,

Mudit