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rtoy / maxima

A Clone of Maxima's repo
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limit x->inf sin(100/x)*x very slow #4101

Open rtoy opened 2 months ago

rtoy commented 2 months ago

Imported from SourceForge on 2024-07-09 16:33:43 Created by macrakis on 2006-04-03 22:44:38 Original: https://sourceforge.net/p/maxima/bugs/895

limit(sin(a/x)*x,x,inf),a=100 takes about 90 seconds on a 1Ghz machine, whereas for a=5 it takes 0.1 seconds, and for unbound a, it takes 0.4 sec.

I am guessing that limit calls trigexpand or some such, leading to completely unnecessary blowup in the intermediate results.

rtoy commented 2 months ago

Imported from SourceForge on 2024-07-09 16:33:43 Created by rtoy on 2006-04-06 12:51:54 Original: https://sourceforge.net/p/maxima/bugs/895/#953f

Logged In: YES user_id=28849

One workaround is to set trigexpandtimes:false. Then it's very fast.

rtoy commented 2 months ago

Imported from SourceForge on 2024-07-09 16:33:47 Created by robert_dodier on 2006-04-09 20:40:11 Original: https://sourceforge.net/p/maxima/bugs/895/#3396