On Jun 21, 4:45 am, Craig McQueen <googlegro...@craig.mcqueen.id.au> wrote: > I've seen some recent discussion about Matrices of e.g. > sympy.polys.domains. I'm very interested, because I'd like to be able > to add, multiply and (most usefully to me) invert matrices of Galois > (finite) fields with modulo 2. > > This relates to a question I asked on StackOverflow, originally about > numpy:http://stackoverflow.com/questions/5578172/can-i-use-my-own-python-cl... > > Originally I planned to do a Galois class myself, and hoped to use it > in numpy or some generic matrix library; but I see sympy provides > sympy.polys.domains.FF so I can do GF2 = sympy.polys.domains.FF(2). > Now all I need is a matrix class that can use elements of that type, > including doing matrix inversion. > > I saw some posts started by Sherjil Ozair discussing possibilities. > What's the current status? Is there some code somewhere that can be > downloaded and tried?
Hello Craig, As you know correctly, part of my project involves making Sympy matrices work for any odd python class. The class will need to have a few things implemented in it, like __add__, __mul__. No, it has not been done as yet. I'm still on phase 1 of my project which is writing sparse matrix algorithms for sympy's symbolic matrices. In a few days however, I'd be releasing two new Matrix class, based on the List of List and the Dict of Keys representations. You would find the work in progress code here [1]. There are two classes, the LILMatrix and the DOKMatrix, which can take in elements of any type. I will be adding a commit shortly which will allow you to set the 'type' of the matrix. So, you will be able to get a matrix with elements of GaloisField. But, according to my understanding and what a mentor has told me, regular algorithms do not apply to matrices over finite field. As yet, algorithms in the Matrix class, and in my DOKMatrix and LILmatrix class, assume (implictly) that the elements belong to the characteristic 0 fields. So, currently sympy doesn't solve matrices over finite fields or is expected to do anytime soon. Matrices over arbitrary dtypes is still possible, and the code will be finished by the end of this month. Still, its worth a shot. If you could post example code, as to what you want to be done, and what you expect the results to be, I'll see if the current algorithms work can be modified to work on it or not. Regards, Sherjil Ozair [1] https://github.com/sherjilozair/sympy/tree/lilmatrix -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to sympy@googlegroups.com. To unsubscribe from this group, send email to sympy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.
