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ratsubst,fullratsubst does not work correctly applied to sum #3867

Open rtoy opened 4 months ago

rtoy commented 4 months ago

Imported from SourceForge on 2024-07-08 20:11:55 Created by zmth on 2015-09-25 21:49:35 Original: https://sourceforge.net/p/maxima/bugs/3029

wxMaxima version: 13.4.0 Maxima version: 5.31.1 Maxima build date: 2013-09-24 09:49:12 Host type: i686-pc-mingw32 Lisp implementation type: GNU Common Lisp (GCL) Lisp implementation version: GCL 2.6.8

(assume(positive,true),assume_pos_pred:true,showtime:true,ratprint:false,load("lrats"),simpsum:true,load(simplify_sum));

:::text
(t:(-1)^(k+m)*sum(sum(binomial(k+m,j)*(1+(-1)^(p-2*j+m))*%i^(p-2*j)*binomial(m,p-2*j),j,max(ceiling((p-m)/2),0)
,min(k,p/2))  *x[1]^(2*k+m-p)*x[2]^p,p,0,2*k+m)
,t1:lratsubst(p=mod(m,2)+2*s,t),ldisp([t ]),ldisp(["t1  ",t1]))

t1 has NO sum over s. Also used fullratsubst and same thing.

rtoy commented 4 months ago

Imported from SourceForge on 2024-07-08 20:11:56 Created by rswarbrick on 2015-10-03 22:40:13 Original: https://sourceforge.net/p/maxima/bugs/3029/#246b

I'm sorry but I'm struggling to understand this bug report. Please can you explain what you expected to see compared to what you actually see? I'm afraid I don't have any intuition for what to expect from summing this complicated pile of binomial coefficients...