Lars Buitinck <larsm...@gmail.com> wrote: > Liblinear uses bad old rand() for its random numbers. That's known to > vary per platform and hard to correctly seed (it's not even > thread-safe).
Few PRNGs are thread-safe: - If you protect the PRNG with a mutex, you will still get a race condition from non-deterministic thread scheduling in the operating system. That means you don't get a deterministic simulation from a fixed random seed. I.e. the PRNG is not algorithmically thread-safe, even though access to the PRNG is serialized. A rand() function might be re-entrant, but that it not sufficient to call it thread-safe! (Ignoring this is a common programming mistake!) - If you provide each thread with its own PRNG, you must make sure the sequences don't overlap. Just using a different seed for each thread is not safe either. You would need something like DCMT to get a really thread-safe PRNG. There are also some PRNGs that allows you to jump ahead to the n-th state in the sequence in O(1) time. Those can be used for multithreading as well. http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/DC/dc.html Sturla ------------------------------------------------------------------------------ Start Your Social Network Today - Download eXo Platform Build your Enterprise Intranet with eXo Platform Software Java Based Open Source Intranet - Social, Extensible, Cloud Ready Get Started Now And Turn Your Intranet Into A Collaboration Platform http://p.sf.net/sfu/ExoPlatform _______________________________________________ Scikit-learn-general mailing list Scikit-learn-general@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/scikit-learn-general
