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A Clone of Maxima's repo
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nusum leaves unsimplified product 2*3 #1579

Closed rtoy closed 2 days ago

rtoy commented 2 days ago

Imported from SourceForge on 2024-07-04 20:16:18 Created by macrakis on 2005-12-13 19:14:13 Original: https://sourceforge.net/p/maxima/bugs/837

nusum(n^2*2^n,n,1,k) => 2*(k^2-2*k+3)*2^k-2*3

Note the unsimplified (-2*3)

Maxima 5.9.2 Using Lisp GNU Common Lisp (GCL) GCL 2.6.7 (aka GCL)

rtoy commented 2 days ago

Imported from SourceForge on 2024-07-04 20:16:19 Created by robert_dodier on 2005-12-19 15:35:04 Original: https://sourceforge.net/p/maxima/bugs/837/#70bd

Logged In: YES user_id=501686

As nusum is superseded by the more recent and extensive Zeilberger package (share/contrib/Zeilberger), I am inclined to close this report as "won't fix". GosperSum doesn't have this bug:

load ("Zeilberger/LOADZeilberger.mac");

GosperSum (n^2*2^n, n, 1, k); => ((k+1)^2-4*(k+1)+6)*2^(k+1)-6

best, Robert Dodier

rtoy commented 2 days ago

Imported from SourceForge on 2024-07-04 20:16:23 Created by robert_dodier on 2006-08-15 02:49:30 Original: https://sourceforge.net/p/maxima/bugs/837/#49a7

rtoy commented 2 days ago

Imported from SourceForge on 2024-07-04 20:16:26 Created by macrakis on 2006-08-15 14:06:10 Original: https://sourceforge.net/p/maxima/bugs/837/#2ea0

Logged In: YES user_id=588346

I traced nusum to make sure this is a nusum and not an underlying Maxima problem -- normally Maxima code can't return unsimplified expressions. It is indeed a nusum problem: it is calling factor on an integer as part of the result. So I agree with Robert that it can be "don't fix".

rtoy commented 2 days ago

Imported from SourceForge on 2024-07-04 20:16:30 Created by andrejv on 2008-04-27 09:51:03 Original: https://sourceforge.net/p/maxima/bugs/837/#0e4e