Hi Alex, On Fri, 20 Nov 2009 11:51:57 -0800 (PST) Alex Raichev <tortoise.s...@gmail.com> wrote:
> Thanks, William. I'll check that out. > > Also, for those interested in the bug i reported, i'd like to rephrase > the description of my situation, because i stated it a little > confusingly above. Take two. I have a big symbolic expression E > involving lots of derivatives. I want to replace the derivatives with > other > symbolic expressions/numbers. Naturally, i'd like to perform the > substitution with a dictionary D whose keys are the derivatives and > whose values are the corresponding expressions/numbers. That is, i > want to build D and do E.subs(D). Unfortunately, building D fails in > Sage 4.2.1 when the keys are derivatives of trivariate (and possibly > n- variate with n>3) functions. (I guess Burcin is getting ready to > work his Sage-fu on this symbolics bug ;-) ) Your original example works for me, with the changes in #7490 applied: http://trac.sagemath.org/sage_trac/ticket/7490 This is only because that patch makes conversions to RIF not use sage.symbolic.expression_conversions module. The real problem that the hashes for the derivatives collide is still there. I can't believe I'm looking at these hashes for the third time. I finally took some time to think about this, and found an (almost) perfect hash function to replace my previous braindead implementation. I hope we won't run into this problem again. :) This is now #7508: http://trac.sagemath.org/sage_trac/ticket/7508 Thanks. Cheers, Burcin -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
