[Pachi] are threads supported for OS X?

Petr Baudis pasky at ucw.cz
Tue May 24 13:01:58 CEST 2011


On Tue, May 24, 2011 at 11:23:04AM +0100, jonathan chetwynd wrote:
> Intel Core 2 Duo
> are threads supported for OS X?

  Yes, they should be.

> twice as quick, but does it play as well?
> my initial impression was maybe not, 

  Especially for initial doublings of playout numbers (either by raising
available time or increasing number of threads), the strength increase
for each doubling should be around one stone.

  However, by default, Pachi's condition for making a move (if you do
not set it in the Go client, e.g. kgsGtp) is fixed at 80000 playouts.
So if you raise number of threads, you will make Pachi play faster,
but not stronger. Perhaps we should change that default, suggestions
about a better one are welcome.

  Use a parameter like `-t 15` to give Pachi 15 seconds per move; then,
raising number of threads will not make Pachi play faster, but instead
play stronger. (In fact, Pachi will take a bit less than 15s to account
for any network lags and other delays.)

> $ ./pachi
> genmove in 14.02s (5706 games/s, 5706 games/s/thread)

> $ ./pachi threads=2
> genmove in 7.23s (11058 games/s, 5529 games/s/thread)

  You can use this information to also verify Pachi's behavior. As you
can see, genmove took less time and number of simulations per second was
double the amount of simulations per second per thread, so indeed two
threads were used.

				Petr "Pasky" Baudis
UNIX is user friendly, it's just picky about who its friends are.

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