[GiNaC-list] Bug in expand
Isuru Fernando
isuruf at gmail.com
Tue May 5 07:48:10 CEST 2015
Hi,
I modified the first benchmark at http://www.ginac.de/csSC-0004015.pdf to,
e = expanded value of (a0 + a1 + sqrt(3)*a2 + sqrt(3)*a3 + ... +
sqrt(3)*a(n-1))^2
in e, substitute a0 with -sqrt(3)*a2 - sqrt(3)*a3 - ... - sqrt(3)*a(n-1)
expand e again to obtain a1^2
For n = 4, I get,
-3*a3^2+2*3*a2^2+a1^2-6*a2^2+3*a3^2
Or
3*a3^2-3*a2^2-3*a3^2+a1^2+3*a2^2
which is true, but not the expression I expected. Why are the terms 3*a2^2
and -3*a2^2, not canceled out immediately? Also a term like 2*3*a2^2 means
there is some bug right?
I am using ginac-1.6.3 on Ubuntu 14.10 with gcc-4.9.1. I am attaching the
sample program.
Isuru Fernando
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