Eric Niebler wrote:
Goran Mitrovic wrote:
Is there a speed comparison with http://research.microsoft.com/projects/greta/ ?
I have some preliminary performance numbers at: http://tinyurl.com/6gefh This is a comparison of dynamic xpressive, static xpressive and Boost.Regex, using the latest versions of both libraries in CVS. I'll see what I can do about getting the numbers for GRETA up there, too. These numbers were achieved using gcc 3.3.3 (cygwin) on my old laptop. Why cygwin? Because I'm hitting a buffer overflow trying to compile the tests on VC7.1. :-P Gotta work around that. The summary: - xpressive does well on short string, often beating Boost.Regex by 4x or more on this test. - Boost.Regex does well on long string, often beating xpressive by 3x or more on this test. - static xpressive usually edges out dynamic xpressive, but not by a lot. I can't say for certain at this point why xpressive is faster on short strings and slower on long ones, but I can guess. I haven't spent much time at this point tuning performance. For xpressive's part, you're seeing the results of brute-force search. No boyer-moore or first-and-follow or special-case handling for narrow character sets ... or anything terribly clever at all. This is clearly hurting xpressive on the long strings, but these things make less of a difference on short matches. xpressive is still quite immature in this regard. I'm very happy with the short string performance, but I bet it's highly sensitive to hardware/compiler configuration. YMMV. The code for this test is checked in at /boost-sandbox/libs/xpressive/perf. -- Eric Niebler Boost Consulting www.boost-consulting.com