[GAP Forum] GAP to MATLAB?

[Hulpke,Alexander]

Dear Forum, Dear Joey,

at the risk of stretching everybodies patience with useless remarks:

> Dear GAP forum,
> 
> Does anybody know of a way to efficiently get matrices (say with cyclotomic entries) from GAP to MATLAB? For instance, is there a package to export matrices as .mat files? 

I think, unless someone has a function to write MATLAB’s binary format (and even then) the size of the objects will be problematic.

What about only transferring two generators, and information on how to build the rest? That is, if you have two (or whatever number) of matrices A and B that generate M12, do the following:

Write A and B to the Matlab file

run through the elements of M12 , preferrably using a permutation representation

Factor every element into the generators A and B, using `Factorization` — for M12 this will be a jiffy.

add code to the matlab file that builds a list/tensor/thingy by forming the corresponding words. (This is building on the assumption that with optimized code matrix multiplication will actually be faster than printing/reading).

(In fact one could even re-use partial words, as done with straight line programs).

Feel free to contact me directly, if you want to do so, but don’t know how to do this on the GAP side.

All the best,

  Alexander Hulpke

-- Colorado State University, Department of Mathematics,
Weber Building, 1874 Campus Delivery, Fort Collins, CO 80523-1874, USA
email: hulpke at colostate.edu, http://www.math.colostate.edu/~hulpke