From 71b8e80384e32113a7c5bb7ef3bf86ab20803e73 Mon Sep 17 00:00:00 2001
From: Petr Baudis <pasky@ucw.cz>
Date: Mon, 30 Jul 2012 22:52:51 +0200
Subject: [PATCH] UCT: Introduce 'maximize_score' preset that turns on adaptive
 dynkomi, val_scale and allow_losing_pass.

---
 README    | 28 +++++++++++++++++++++++++++-
 uct/uct.c | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+), 1 deletion(-)

diff --git a/README b/README
index 9225e4f..8afda73 100644
--- a/README
+++ b/README
@@ -47,6 +47,8 @@ improvements have been already achieved. We rigorously play-test new
 features and enable them by default only when they give a universal
 strength boost.
 
+How to run
+~~~~~~~~~~
 
 By default, Pachi will run on a single CPU core, taking up to 1.4GiB
 of memory, not pondering and taking completely arbitrary amount of time
@@ -80,6 +82,31 @@ in uct/uct.c - you will find the list of UCT engine options there, each
 with a description. At any rate, usually the three options above are
 the only ones you really want to tweak.
 
+Greedy Pachi
+~~~~~~~~~~~~
+
+Normally, Pachi cares only for win or loss and does not take into
+account the point amount. This means that it will play slack endgame
+when winning and crazy moves followed with a resign when losing.
+
+It may give you a more pleasurable playing experience if Pachi
+_does_ take into account the point size, strives for a maximum
+(reasonable) win margin when winning and minimal point loss when
+losing. This is possible by using the maximize_score parameter, e.g.:
+
+	./pachi -t _1200 threads=8,pondering,maximize_score
+
+This enables an aggressive dynamic komi usage and end result margin
+is included in node values aside of winrate. Pachi will also enter
+scoring even when losing (normally, Pachi will never pass in that case).
+Note that if you pass any 'dynkomi' parameter to Pachi, you will reset
+the values set by 'maximize_score'.
+
+Note that Pachi in this mode may be slightly weaker, and result margin
+should not be taken into account when judging either player's strength.
+
+Experiments and Testing
+~~~~~~~~~~~~~~~~~~~~~~~
 
 Except UCT, Pachi supports a simple idiotbot-like engine and an example
 treeless MonteCarlo-player. The MonteCarlo simulation ("playout")
@@ -95,7 +122,6 @@ Other special engines are also provided:
   learned patterns
 * few other purely for development usage
 
-
 Pachi can be used as a test opponent for development of other go-playing
 programs. For example, to get the "plainest UCT" player, use:
 
diff --git a/uct/uct.c b/uct/uct.c
index e29a267..a199d62 100644
--- a/uct/uct.c
+++ b/uct/uct.c
@@ -1053,6 +1053,40 @@ uct_state_init(char *arg, struct board *b)
 				 * replying to the genmoves command (in ms) */
 				u->stats_delay = 0.001 * atof(optval);
 
+			/** Presets */
+
+			} else if (!strcasecmp(optname, "maximize_score")) {
+				/* A combination of settings that will make
+				 * Pachi try to maximize his points (instead
+				 * of playing slack yose) or minimize his loss
+				 * (and proceed to counting even when losing). */
+				/* Please note that this preset might be
+				 * somewhat weaker than normal Pachi, and the
+				 * score maximization is approximate; point size
+				 * of win/loss still should not be used to judge
+				 * strength of Pachi or the opponent. */
+				/* See README for some further notes. */
+				if (!optval || atoi(optval)) {
+					/* Allow scoring a lost game. */
+					u->allow_losing_pass = true;
+					/* Make Pachi keep his calm when losing
+					 * and/or maintain winning marging. */
+					/* Do not play games that are losing
+					 * by too much. */
+					/* XXX: komi_ratchet_age=40000 is necessary
+					 * with losing_komi_ratchet, but 40000
+					 * is somewhat arbitrary value. */
+					char dynkomi_args[] = "losing_komi_ratchet:komi_ratchet_age=60000:no_komi_at_game_end=0:max_losing_komi=30";
+					u->dynkomi = uct_dynkomi_init_adaptive(u, dynkomi_args, b);
+					/* XXX: Values arbitrary so far. */
+					/* XXX: Also, is bytemp sensible when
+					 * combined with dynamic komi?! */
+					u->val_scale = 0.01;
+					u->val_bytemp = true;
+					u->val_bytemp_min = 0.001;
+					u->val_byavg = true;
+				}
+
 			} else {
 				fprintf(stderr, "uct: Invalid engine argument %s or missing value\n", optname);
 				exit(1);
-- 
2.11.4.GIT