From: Alexei Sheplyakov <varg@metalica.kh.ua>
Date: Mon, 16 Feb 2009 14:23:16 +0000 (+0200)
Subject: Univariate GCD timing: use sr_gcd when appropriate.
X-Git-Tag: release_1-5-0
X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?a=commitdiff_plain;h=cbba7a5eb9d33003c081a8017dec7da3aa990571;p=ginac.git

Univariate GCD timing: use sr_gcd when appropriate.

The benchmark consists of two parts:
1) timing of different GCD calculation methods (i.e. subresultant PRS,
   heuristic, chinese remaindering).
2) timing of different implementations of the same method. The purpose
   is to find out how (in)efficient GiNaC::ex is as a representation
   of (univariate) polynomials (as a side note, the result is a bit
   depressing -- using coefficient vector instead of GiNaC:ex makes
   GCD calculation 50x -- 1000x faster).

Now GiNaC uses modular (chinese remaindering) GCD by default, so part 2)
got broken, i.e. instead of (intended) timings

a) (heuristic, GiNaC::ex) versus (heuristic, coefficient vector)
b) (PRS, GiNaC::ex) versus (PRS, coefficient vector)

one gets

a') (heuristic, GiNaC::ex) versus (heuristic, coefficient vector)
b') (chinese remaindering, GiNaC::ex) versus (PRS, coefficient vector)

Set the gcd_options::use_sr_gcd to restore the meaning of the benchmark.

Note: this patch does not affect the library proper.
---

diff --git a/check/time_uvar_gcd.cpp b/check/time_uvar_gcd.cpp
index c65c515b..fe758974 100644
--- a/check/time_uvar_gcd.cpp
+++ b/check/time_uvar_gcd.cpp
@@ -1780,7 +1780,8 @@ struct ex_sr_gcd_test
 	const upoly& g_check;
 	unsigned options;
 	ex_sr_gcd_test(const ex& a_, const ex& b_, const upoly& g_) :
-		a(a_), b(b_), g(0), g_check(g_), options(gcd_options::no_heur_gcd)
+		a(a_), b(b_), g(0), g_check(g_), options(gcd_options::no_heur_gcd |
+				                         gcd_options::use_sr_gcd)
 	{ }
 
 	inline void run()