If your PRNG is consuming 40% of your CPU time, your playouts are too light.
Anyway, it's very easy to make a fast PRNG these days. The first thing that comes to mind is a 64-bit linear congruential generator of which you use the middle bits, or you can XOR the high 32 bits and the low 32 bits together. LCGs have well-understood limitations that don't really matter for a go program. If you want higher-quality PRNs you need to use a large state, but you can still make it be very fast. Still, try the LCG first. I would be surprised if you find any degradation in strength of your engine compared to the Mersenne twister. Álvaro. On Sun, Mar 29, 2015 at 12:05 PM, folkert <folk...@vanheusden.com> wrote: > Ah! > But how do you make sure the numbers are uniformly distributed? > > On Sun, Mar 29, 2015 at 05:58:56PM +0800, remco.bloe...@singularityu.org > wrote: > > I switched to SFMT [0]. But that was some years ago, there might be > faster options now. > > > > I also generated it in megabyte batches and consume it from there, > generating a new megabyte as needed. > > > > Lastly, I had some code to make sure I did not consume more bits of > entropy than required. Two uniform choices, one bit. Three choices: > fractional bits. > > > > [0] > > > > http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/SFMT/ > > > > ??? Remco > > > > -----Original Message----- > > From: folkert <folk...@vanheusden.com> > > To: computer-go@computer-go.org > > Sent: Sun, 29 Mar 2015 17:50 > > Subject: [Computer-go] fast + good RNG > > > > Hi, > > > > I measured that std::mt19937_64 (the mersenne twister from the standard > > c++ libraries) uses about 40% cpu time during playouts. > > > > So I wonder: is there a faster prng while still generating good enough > > random? > > > > > > Folkert van Heusden > > > > -- > > Nagios user? Check out CoffeeSaint - the versatile Nagios status > > viewer! http://www.vanheusden.com/java/CoffeeSaint/ > > ---------------------------------------------------------------------- > > Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com > > _______________________________________________ > > Computer-go mailing list > > Computer-go@computer-go.org > > http://computer-go.org/mailman/listinfo/computer-go > > > _______________________________________________ > > Computer-go mailing list > > Computer-go@computer-go.org > > http://computer-go.org/mailman/listinfo/computer-go > > > > Folkert van Heusden > > -- > MultiTail er et flexible tool for å kontrolere Logfiles og commandoer. > Med filtrer, farger, sammenføringer, forskeliger ansikter etc. > http://www.vanheusden.com/multitail/ > ---------------------------------------------------------------------- > Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com > _______________________________________________ > Computer-go mailing list > Computer-go@computer-go.org > http://computer-go.org/mailman/listinfo/computer-go >
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