[GiNaC-devel] [PATCH] gcd: fix heuristics to chose main variable properly

[Richard B. Kreckel]

Dear Alexei,

Alexei Sheplyakov wrote:

>[on a Pentium 4 3GHz box]
>$ g++ -O2 -march=pentium4 -finline-limit=1200 thepoly_another.cpp -o thepoly_another -lginac
>$ time ./thepoly_another >/dev/null 2>&1
>
>real    0m7.846s
>user    0m7.836s
>sys     0m0.008s
>
>With unpatched GiNaC it takes way to long (after several days of
>calculation I get bored and killed the process).
>  
>

As a challenge, could you please have a look at the Lewis-Wester 
benchmarks M2, N, and O2 in files check/time_lw_M2.cpp, 
check/time_lw_N.cpp, and check/time_lw_M2.cpp, respectively? They all 
contain a boolean variable which is used to turn disable these tests. 
And they are all about GCDs. Some of them have never ever run to completion.

BTW: May we assume that your little patch makes the GCD also much more 
memory effective?

Regards
  -richy.

-- 
Richard B. Kreckel
<http://www.ginac.de/~kreckel/>