Re: [Bug-gnubg] Rollout with 'Stop when result is accurate'

[Yoshito Takeuchi]

Hi Philippe Michel

Great thanks for your reply.

Sorry, I didn't understand the function.
And I tried your patch and rollout.
It is just the function for me !!!

Thanks again

Yoshito Takeuchi

> 'Stop when STDs are small enough' may not do what you seem to be expecting.
> As stated, it stops when Standard Deviation/Value (not equity sd) is below
> the limit you set *for every output* : singles wins, gammons, backgammons
> for both players, cubeless and cubeful equity.
>
> In practice, this criterion is useless : backgammon numbers are often very
> noisy, if the equity is close to 0, sd/equity is high, etc...
>
> Since you compile from source, you may want to apply the appended patch that
> changes the criterion to 'stop when equity sd is small enough'.
>
> With it, I get results like :
>
> Rollout details:
> Centered 1-cube:
>  0.71334 0.02413 0.00064 - 0.28666 0.02212 0.00057 CL  +0.42875 CF +0.72226
>  [0.00030 0.00028 0.00006 - 0.00030 0.00025 0.00004 CL   0.00070 CF 0.00175]
> Player gnubg owns 2-cube:
>  0.71590 0.02384 0.00063 - 0.28410 0.02205 0.00057 CL  +0.86731 CF +0.71301
>  [0.00031 0.00029 0.00006 - 0.00031 0.00026 0.00004 CL   0.00141 CF 0.00200]
> Full cubeful rollout with var.redn.
> 12051 games, Mersenne Twister dice gen. with seed 868626794 and quasi-random
> dice
> Stop when std.errs. are small enough: ratio 0.002 (min. 1296 games)
>
> which may be what you want. With stock gnubg, it wouldn't have stopped there
> since for instance sd(bg)/bg for the player on roll is about 0.1, 50 times
> too high!
>
> Index: rollout.c
> ===================================================================
> RCS file: /sources/gnubg/gnubg/rollout.c,v
> retrieving revision 1.221
> diff -u -r1.221 rollout.c
> --- rollout.c   1 Oct 2009 21:05:54 -0000       1.221
> +++ rollout.c   31 Oct 2009 19:20:15 -0000
> @@ -1216,7 +1216,7 @@
>                                if (fNoMore[alt] || altGameCount[alt] <
> (rcRollout.nMinimumGames ))
>                                        continue;
>                                prc = &ro_apes[alt]->rc;
> -                               for (output = 0; output <
> NUM_ROLLOUT_OUTPUTS; output++) {
> +                               for (output = OUTPUT_EQUITY; output <
> NUM_ROLLOUT_OUTPUTS; output++) {
>                                        if (output < OUTPUT_EQUITY) {
>                                                v = fabs(aarMu[alt][output]);
>                                                s =
> fabs(aarSigma[alt][output]);
> @@ -1249,8 +1249,7 @@
>
> &aciLocal[(ro_fCubeRollout ? 0 : alt)]));
>                                                }
>                                        }
> -
> -                                       if ((v >= .0001) && (v *
> rcRollout.rStdLimit < s)) {
> +                                       if ( rcRollout.rStdLimit < s) {
>                                                err_too_big = 1;
>                                                break;
>                                        }
>
> PS: Jon, Christian, how about applying this change (or something to that
> effect), plus the corresponding update the UI ? I insist : the current
> behaviour of this criterion is just useless!
>
>