Re: [ublas] Question/request for matrix powers and other stuff

Subject: Re: [ublas] Question/request for matrix powers and other stuff
From: Paul C. Leopardi (paul.leopardi_at_[hidden])
Date: 2008-10-21 19:20:38

On Fri, 26 Sep 2008, Daryle Walker wrote:
> 2.	Is there a matrix type with Boolean elements?  I worked around
> that my making my own GF(2) representation type and using it with the
> uBLAS class templates.  Is using a type that doesn't represent real
> or complex numbers supported?  I wonder if there could be such GF(2)
> vector and matrix types, maybe the elements can be compacted into
> single bits.
>
> (I'm developing a type that implement linear transformations of
> binary objects as matrices, so repeated applications of a particular
> transformation would be implemented as a power.  I originally tried
> to develop my own compact-bit vector and matrix class templates, but
> thought it was too much to test it and my main code, so I made a [non-
> compact] GF(2) class and wrapped uBLAS around that.)
Daryle,
I've recently attended Sage Days 10 - http://wiki.sagemath.org/days10 . 
Perhaps you woule be interested in the talk given by Martin Albrect 
on "Matrix Multiplication over GF(2) in the M4RI Library":  
http://www.informatik.uni-bremen.de/%7Emalb/talks/20081010%20-%20M4RI%20-%20Nancy.pdf
The multiplication uses Gray codes and table lookup.
Best, Paul