Try making x0 sparse before multiplying; when you multiply sparse by dense by default Sage turns the spare object into a dense one rather than the dense into sparse. David
On Thu, Jun 26, 2025 at 9:24 PM Ricardo Fodra <ricardo.fo...@gmail.com> wrote: > Why am I running out of memory when I multiply a sparse matrix and a > vector: > > sage: A > 71604 x 143208 sparse matrix over Real Field with 53 bits of precision > (use the '.str()' method to see the entries) > sage: A.density() > 95465/3418088544 > sage: x0 > 143208 x 1 dense matrix over Real Field with 53 bits of precision (use the > '.str()' method to see the entries) > sage: x1 = A * x0 > (after a while... out of memory) > > -- > You received this message because you are subscribed to the Google Groups > "sage-devel" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sage-devel+unsubscr...@googlegroups.com. > To view this discussion visit > https://groups.google.com/d/msgid/sage-devel/05a8147d-1b2f-411b-a06e-24dfc9d7ad71n%40googlegroups.com > <https://groups.google.com/d/msgid/sage-devel/05a8147d-1b2f-411b-a06e-24dfc9d7ad71n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To view this discussion visit https://groups.google.com/d/msgid/sage-devel/CAChs6_nqzkrF6y0zK5rLRdXuh%3Db5T%3DNih-UzsA0nujpN3205bA%40mail.gmail.com.
