This is now https://trac.sagemath.org/ticket/28586
It would be great not to have to do git bisect on this, anyone can point out to a suspect ticket? Thanks! On Thu, Oct 10, 2019 at 12:06 AM Robert Samal <robert.sa...@gmail.com> wrote: > Indeed it works in Sage 8.4. > Thanks! > > On Wednesday, October 9, 2019 at 8:34:41 AM UTC-7, Dima Pasechnik wrote: >> >> This got broken in Sage 8.5. >> (still works in 8.4) >> >> >> >> On Wed, Oct 9, 2019 at 6:09 AM David Joyner <wdjo...@gmail.com> wrote: >> >>> >>> >>> On Wed, Oct 9, 2019 at 1:33 AM Robert Samal <rober...@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-s...@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-s...@googlegroups.com. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/sage-support/CAEQuuAWQYKhtkVme8wHkJTj38QkmfnSJf3_Lhtqj9PxJmq8HcQ%40mail.gmail.com >>> <https://groups.google.com/d/msgid/sage-support/CAEQuuAWQYKhtkVme8wHkJTj38QkmfnSJf3_Lhtqj9PxJmq8HcQ%40mail.gmail.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/5ce4410e-1ee7-4ebd-a5a6-903e893c1b77%40googlegroups.com > <https://groups.google.com/d/msgid/sage-support/5ce4410e-1ee7-4ebd-a5a6-903e893c1b77%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/CAAWYfq3Vx0K5YT_WM_M280f1%2B_5uQp0vuPYrHGaVdncR1vC2Aw%40mail.gmail.com.
