-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi, I'm experiencing a bug with the boost::random library. Apparently, most generators, together with uniform_int<>, produce heavily biased sequences. I'm sending attached a small test program which generates several random walks on a lattice, starting from the center, and counts how many times a site has been visited. It uses both the boost::random generators, and the tr1::random generators from GCC 4.3, and writes the separate counts in the files "bcount" and "tcount", respectively. A plot of the output with boost::random can be seen here: http://dl.getdropbox.com/u/280654/boost_random.png There is an obvious tendency towards the (0,0) corner of the lattice... With tr1::random, everything looks normal: http://dl.getdropbox.com/u/280654/tr1_random.png Not to mention I used the same generator (mt19937) with the same seed value in both cases, which should have given the exact same sequence! I obtain similar results with other generators, except with minstd_rand, where the sequences from both libraries are the same. This lead me to conclude that the problem is with the generators themselves, not with uniform_int<>. More info on my end: platform: x86_64 intel, GNU/Linux GCC: 4.3.3 Boost: 1.37 Best regards, Tiago -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.11 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEARECAAYFAkoXu/8ACgkQBNxGHvNv411+4QCfSfgo1Mu1lROQhwPnGxtEoq51 C1MAn1GJi0BYVtyExFmfdsxvtpKOM/fk =CsWe -----END PGP SIGNATURE-----