one should not be using sagecell.sagemath.org server for teaching, it's not scaling well (compared to cocalc.com, say) under load.
unleashing undergraduates to compute on it surely gets things very slow there On 28 November 2023 15:45:33 GMT, Eric Gourgoulhon <egourgoul...@gmail.com> wrote: >Hi, > >I've also noticed two days ago that https://sagecell.sagemath.org/ is very >slow (actually does not terminate) even on elementary operations. >Maybe there is a problem with the server at the moment... > >Eric. > >Le mardi 28 novembre 2023 à 16:36:30 UTC+1, Fernando Q. Gouvea a écrit : > >> Yesterday I was demonstrating to my calculus class Sage's ability to >> implement the method of Lagrange multipliers. I used a standard example, >> putting the following code into SageMath Cell: >> >> var('x,y,l') >> f(x,y)=10*x^(1/3)*y^(2/3) >> g(x,y)=5*x-6*y >> fx=diff(f,x) >> fy=diff(f,y) >> gx=diff(g,x) >> gy=diff(g,y) >> solve((fx(x,y)==l*gx(x,y),fy(x,y)==l*gy(x,y),g(x,y)==120),(x,y,l)) >> >> That works beautifully. Then I decided to show off Sage's powers by >> making a little change: >> >> var('x,y,l') >> f(x,y)=10*x^(1/3)*y^(2/3) >> g(x,y)=5*x^2+6*y >> fx=diff(f,x) >> fy=diff(f,y) >> gx=diff(g,x) >> gy=diff(g,y) >> solve((fx(x,y)==l*gx(x,y),fy(x,y)==l*gy(x,y),g(x,y)==120),(x,y,l)) >> >> SageCell now gives me a spinning symbol ("I'm working") for a while, >> then seems to exit without any result. On my local installation (Sage >> 9.2 on Windows) it returns an empty list, []. >> >> What is curious is that the constraint equation 5x^2 + 6y=120 is easily >> solved for y... >> >> Questions: >> >> 1) Shouldn't SageCell output an empty list here? >> >> 2) Is this a known limitation of "solve"? >> >> Fernando >> >> PS: It seems that if I add "algorithm='sympy'" then solutions are found. >> >> -- >> ================================================================== >> Fernando Q. Gouvea >> Carter Professor of Mathematics >> Colby College >> Mayflower Hill 5836 >> Waterville, ME 04901 >> fqgo...@colby.edu http://www.colby.edu/~fqgouvea >> >> >> >> > >-- >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/8f554c04-42d9-4765-bd3a-a82bd2758bddn%40googlegroups.com. -- 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/FA17F134-394F-46B4-814B-0A75072F01F3%40gmail.com.
