On Wed, Oct 9, 2019 at 1:33 AM Robert Samal <robert.sa...@gmail.com> wrote:
> Sorry, F=GF(3), I made my original example shorter and didn't read it > properly. > > So the full problematic code is > > B=matrix(GF(3), 2,2,[1,0,1,0], sparse=True) > v=vector(GF(3), [1,1]) > B.solve_right(v) > > Yes. I can confirm it works with "sparse=True" removed *or* if GF(3) is replaced by ZZ. So there's an easy workaround but maybe the docs or the code has a bug? Thanks for reporting. Thanks, > > Robert > > > On Tuesday, October 8, 2019 at 5:17:59 PM UTC-7, Robert Samal wrote: >> >> I am trying to solve a rather large linear systems of equations of GF(3). >> As the matrices are sparse, I thought that adding "sparse=True" to the >> constructor of the matrix could be of help. However, I ran to a strange >> error message. >> >> B=matrix(GF(3), 2,2,[1,0,1,0], sparse=True) >> v=vector(F, [1,1]) >> B.solve_right(v) >> >> The above code yields the following >> >> TypeError: Cannot convert sage.matrix.matrix_modn_sparse.Matrix_modn_sparse >> to sage.matrix.matrix_integer_sparse.Matrix_integer_sparse >> >> >> I am hesitant to paste the whole error message here, but it ends with >> reference to file >> SageMath/local/lib/python2.7/site-packages/sage/matrix/matrix_modn_sparse.pyx >> in >> sage.matrix.matrix_modn_sparse.Matrix_modn_sparse._solve_matrix_linbox >> (build/cythonized/sage/matrix/matrix_modn_sparse.cpp:11633). >> >> I am using Sage 8.9, but the same issue was on 8.7 as well. >> >> Few other observations: >> -- works as expected for dense matrices -- or for sparse ones over integers >> -- the same issue occurs whether y is a vector or a matrix >> -- It behaves the same for systems with no solution. >> >> Is there some hidden limitation of sparse matrices over finite fields? >> I.e., is it a bug or feature? :-) >> I tried to RTFM, but couldn't find this discussed. The page for sparse >> matrices over >> finite fields does not exactly promise the solve method, but it does not >> mention it >> would not work either. Is it possible to achieve what I want by other means >> (in Sage). >> >> Thanks. >> >> >> >> >> -- > You received this message because you are subscribed to the Google Groups > "sage-support" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sage-support+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sage-support/6ac68e19-7c5a-4be1-ba10-1bac22cddc62%40googlegroups.com > <https://groups.google.com/d/msgid/sage-support/6ac68e19-7c5a-4be1-ba10-1bac22cddc62%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-support/CAEQuuAWQYKhtkVme8wHkJTj38QkmfnSJf3_Lhtqj9PxJmq8HcQ%40mail.gmail.com.
