On Apr 4, 2011, at 11:30 PM, Brian Granger wrote: > Hi, > >> Could you give an example of how you construct large sparse matrices. >> What sort of constructors would you like to see in the class ? > > Our big sparse matrices are formed out of tensor products of 2x2 > matrices, such as Pauli and Hadamard matrices. But these tensor > products have *many* identity matrices as well, which makes them > sparse. Here is our matrix tensor product code: > > https://github.com/sympy/sympy/blob/master/sympy/physics/quantum/matrixutils.py#L232 > > > Here is some specific examples: > > In [1]: from sympy.physics.quantum import * > > In [2]: from sympy.physics.quantum.gate import * > > In [3]: g = X(2) > > In [4]: represent(g, nqubits=4) > > You could also look at what happens when you increase nqubits and also look > at: > > g = Y(2) > g = H(2) > > 2 could also be any number < nqubits > > In many ways one of the most useful things we could have would be a > sparse tensor product. > >> Are there any special class of sparse matrices that you guys use >> often, like tridiagonal matrix or permutation matrix ? > > Nope, in practice we get matrices that look quite different and have > different sparsities. > >>>> I should also mention that we are >> pretty much only interested in matrix-vector multiplies, matrix- >> scalar >> mult. and matrix addition. > >> Arent you also interested in solving A * x = B, or matrix-matrix >> mult ? > > Nope for this particular application, we don't need linear solves or > matrix-matrix mul.
So what do you do with the matrices? Aaron Meurer > > Cheers, > > Brian > >> Thank you for your help, >> Sherjil Ozair >> >> -- >> 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. >> >> > > > > -- > Brian E. Granger > Cal Poly State University, San Luis Obispo > bgran...@calpoly.edu and elliso...@gmail.com > > -- > 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. > -- 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.
