uct/policy/ucb1amaf.c

   1 #include <assert.h>
   2 #include <math.h>
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5 #include <string.h>
   6
   7 #include "board.h"
   8 #include "debug.h"
   9 #include "move.h"
  10 #include "random.h"
  11 #include "uct/internal.h"
  12 #include "uct/tree.h"
  13 #include "uct/policy/generic.h"
  14
  15 /* This implements the UCB1 policy with an extra AMAF heuristics. */
  16
  17 struct ucb1_policy_amaf {
  18         /* This is what the Modification of UCT with Patterns in Monte Carlo Go
  19          * paper calls 'p'. Original UCB has this on 2, but this seems to
  20          * produce way too wide searches; reduce this to get deeper and
  21          * narrower readouts - try 0.2. */
  22         floating_t explore_p;
  23         /* First Play Urgency - if set to less than infinity (the MoGo paper
  24          * above reports 1.0 as the best), new branches are explored only
  25          * if none of the existing ones has higher urgency than fpu. */
  26         floating_t fpu;
  27         unsigned int equiv_rave;
  28         bool check_nakade;
  29         bool sylvain_rave;
  30         /* Coefficient of local tree values embedded in RAVE. */
  31         floating_t ltree_rave;
  32         /* Coefficient of criticality embedded in RAVE. */
  33         floating_t crit_rave;
  34         int crit_min_playouts;
  35         bool crit_negative;
  36         bool crit_amaf;
  37 };
  38
  39
  40 static inline floating_t fast_sqrt(unsigned int x)
  41 {
  42         static const floating_t table[] = {
  43                 0, 1, 1.41421356237309504880, 1.73205080756887729352,
  44                 2.00000000000000000000, 2.23606797749978969640,
  45                 2.44948974278317809819, 2.64575131106459059050,
  46                 2.82842712474619009760, 3.00000000000000000000,
  47                 3.16227766016837933199, 3.31662479035539984911,
  48                 3.46410161513775458705, 3.60555127546398929311,
  49                 3.74165738677394138558, 3.87298334620741688517,
  50                 4.00000000000000000000, 4.12310562561766054982,
  51                 4.24264068711928514640, 4.35889894354067355223,
  52                 4.47213595499957939281, 4.58257569495584000658,
  53                 4.69041575982342955456, 4.79583152331271954159,
  54                 4.89897948556635619639, 5.00000000000000000000,
  55                 5.09901951359278483002, 5.19615242270663188058,
  56                 5.29150262212918118100, 5.38516480713450403125,
  57                 5.47722557505166113456, 5.56776436283002192211,
  58                 5.65685424949238019520, 5.74456264653802865985,
  59                 5.83095189484530047087, 5.91607978309961604256,
  60                 6.00000000000000000000, 6.08276253029821968899,
  61                 6.16441400296897645025, 6.24499799839839820584,
  62                 6.32455532033675866399, 6.40312423743284868648,
  63                 6.48074069840786023096, 6.55743852430200065234,
  64                 6.63324958071079969822, 6.70820393249936908922,
  65                 6.78232998312526813906, 6.85565460040104412493,
  66                 6.92820323027550917410, 7.00000000000000000000,
  67                 7.07106781186547524400, 7.14142842854284999799,
  68                 7.21110255092797858623, 7.28010988928051827109,
  69                 7.34846922834953429459, 7.41619848709566294871,
  70                 7.48331477354788277116, 7.54983443527074969723,
  71                 7.61577310586390828566, 7.68114574786860817576,
  72                 7.74596669241483377035, 7.81024967590665439412,
  73                 7.87400787401181101968, 7.93725393319377177150,
  74         };
  75         if (x < sizeof(table) / sizeof(*table)) {
  76                 return table[x];
  77         } else {
  78                 return sqrt(x);
  79         }
  80 }
  81
  82 #define URAVE_DEBUG if (0)
  83 static floating_t inline
  84 ucb1rave_evaluate(struct uct_policy *p, struct tree *tree, struct uct_descent *descent, int parity)
  85 {
  86         struct ucb1_policy_amaf *b = p->data;
  87         struct tree_node *node = descent->node;
  88         struct tree_node *lnode = descent->lnode;
  89
  90         struct move_stats n = node->u, r = node->amaf;
  91         if (p->uct->amaf_prior) {
  92                 stats_merge(&r, &node->prior);
  93         } else {
  94                 stats_merge(&n, &node->prior);
  95         }
  96
  97         /* Local tree heuristics. */
  98         assert(!lnode || lnode->parent);
  99         if (p->uct->local_tree && b->ltree_rave > 0 && lnode
 100             && (p->uct->local_tree_rootchoose || lnode->parent->parent)) {
 101                 struct move_stats l = lnode->u;
 102                 l.playouts = ((floating_t) l.playouts) * b->ltree_rave / LTREE_PLAYOUTS_MULTIPLIER;
 103                 URAVE_DEBUG fprintf(stderr, "[ltree] adding [%s] %f%%%d to [%s] RAVE %f%%%d\n",
 104                         coord2sstr(node_coord(lnode), tree->board), l.value, l.playouts,
 105                         coord2sstr(node_coord(node), tree->board), r.value, r.playouts);
 106                 stats_merge(&r, &l);
 107         }
 108
 109         /* Criticality heuristics. */
 110         if (b->crit_rave > 0 && node->u.playouts > b->crit_min_playouts) {
 111                 floating_t crit = tree_node_criticality(tree, node);
 112                 if (b->crit_negative || crit > 0) {
 113                         struct move_stats c = {
 114                                 .value = tree_node_get_value(tree, parity, 1.0f),
 115                                 .playouts = crit * r.playouts * b->crit_rave
 116                         };
 117                         URAVE_DEBUG fprintf(stderr, "[crit] adding %f%%%d to [%s] RAVE %f%%%d\n",
 118                                 c.value, c.playouts,
 119                                 coord2sstr(node_coord(node), tree->board), r.value, r.playouts);
 120                         stats_merge(&r, &c);
 121                 }
 122         }
 123
 124
 125         floating_t value = 0;
 126         if (n.playouts) {
 127                 if (r.playouts) {
 128                         /* At the beginning, beta is at 1 and RAVE is used.
 129                          * At b->equiv_rate, beta is at 1/3 and gets steeper on. */
 130                         floating_t beta;
 131                         if (b->sylvain_rave) {
 132                                 beta = (floating_t) r.playouts / (r.playouts + n.playouts
 133                                         + (floating_t) n.playouts * r.playouts / b->equiv_rave);
 134                         } else {
 135                                 /* XXX: This can be cached in descend; but we don't use this by default. */
 136                                 beta = sqrt(b->equiv_rave / (3 * node->parent->u.playouts + b->equiv_rave));
 137                         }
 138
 139                         value = beta * r.value + (1.f - beta) * n.value;
 140                         URAVE_DEBUG fprintf(stderr, "\t%s value = %f * %f + (1 - %f) * %f (prior %f)\n",
 141                                 coord2sstr(node_coord(node), tree->board), beta, r.value, beta, n.value, node->prior.value);
 142                 } else {
 143                         value = n.value;
 144                         URAVE_DEBUG fprintf(stderr, "\t%s value = %f (prior %f)\n",
 145                                 coord2sstr(node_coord(node), tree->board), n.value, node->prior.value);
 146                 }
 147         } else if (r.playouts) {
 148                 value = r.value;
 149                 URAVE_DEBUG fprintf(stderr, "\t%s value = rave %f (prior %f)\n",
 150                         coord2sstr(node_coord(node), tree->board), r.value, node->prior.value);
 151         }
 152         descent->value.playouts = r.playouts + n.playouts;
 153         descent->value.value = value;
 154         return tree_node_get_value(tree, parity, value);
 155 }
 156
 157 void
 158 ucb1rave_descend(struct uct_policy *p, struct tree *tree, struct uct_descent *descent, int parity, bool allow_pass)
 159 {
 160         struct ucb1_policy_amaf *b = p->data;
 161         floating_t nconf = 1.f;
 162         if (b->explore_p > 0)
 163                 nconf = sqrt(log(descent->node->u.playouts + descent->node->prior.playouts));
 164
 165         uctd_try_node_children(tree, descent, allow_pass, parity, p->uct->tenuki_d, di, urgency) {
 166                 struct tree_node *ni = di.node;
 167                 urgency = ucb1rave_evaluate(p, tree, &di, parity);
 168
 169                 if (ni->u.playouts > 0 && b->explore_p > 0) {
 170                         urgency += b->explore_p * nconf / fast_sqrt(ni->u.playouts);
 171
 172                 } else if (ni->u.playouts + ni->amaf.playouts + ni->prior.playouts == 0) {
 173                         /* assert(!u->even_eqex); */
 174                         urgency = b->fpu;
 175                 }
 176         } uctd_set_best_child(di, urgency);
 177
 178         uctd_get_best_child(descent);
 179 }
 180
 181
 182 void
 183 ucb1amaf_update(struct uct_policy *p, struct tree *tree, struct tree_node *node,
 184                 enum stone node_color, enum stone player_color,
 185                 struct playout_amafmap *map, struct board *final_board,
 186                 floating_t result)
 187 {
 188         struct ucb1_policy_amaf *b = p->data;
 189         enum stone winner_color = result > 0.5 ? S_BLACK : S_WHITE;
 190         enum stone child_color = stone_other(node_color);
 191
 192 #if 0
 193         struct board bb; bb.size = 9+2;
 194         for (struct tree_node *ni = node; ni; ni = ni->parent)
 195                 fprintf(stderr, "%s ", coord2sstr(node_coord(ni), &bb));
 196         fprintf(stderr, "[color %d] update result %d (color %d)\n",
 197                         node_color, result, player_color);
 198 #endif
 199
 200         while (node) {
 201                 if (node->parent == NULL)
 202                         assert(tree->root_color == stone_other(child_color));
 203
 204                 if (!b->crit_amaf && !is_pass(node_coord(node))) {
 205                         stats_add_result(&node->winner_owner, board_at(final_board, node_coord(node)) == winner_color ? 1.0 : 0.0, 1);
 206                         stats_add_result(&node->black_owner, board_at(final_board, node_coord(node)) == S_BLACK ? 1.0 : 0.0, 1);
 207                 }
 208                 stats_add_result(&node->u, result, 1);
 209                 if (!is_pass(node_coord(node)) && amaf_nakade(map->map[node_coord(node)]))
 210                         amaf_op(map->map[node_coord(node)], -);
 211
 212                 /* This loop ignores symmetry considerations, but they should
 213                  * matter only at a point when AMAF doesn't help much. */
 214                 assert(map->game_baselen >= 0);
 215                 for (struct tree_node *ni = node->children; ni; ni = ni->sibling) {
 216                         enum stone amaf_color = map->map[node_coord(ni)];
 217                         assert(amaf_color != S_OFFBOARD);
 218                         if (amaf_color == S_NONE)
 219                                 continue;
 220                         if (amaf_nakade(map->map[node_coord(ni)])) {
 221                                 if (!b->check_nakade)
 222                                         continue;
 223                                 unsigned int i;
 224                                 for (i = map->game_baselen; i < map->gamelen; i++)
 225                                         if (map->game[i].coord == node_coord(ni)
 226                                             && map->game[i].color == child_color)
 227                                                 break;
 228                                 if (i == map->gamelen)
 229                                         continue;
 230                                 amaf_color = child_color;
 231                         }
 232
 233                         floating_t nres = result;
 234                         if (amaf_color != child_color) {
 235                                 continue;
 236                         }
 237                         /* For child_color != player_color, we still want
 238                          * to record the result unmodified; in that case,
 239                          * we will correctly negate them at the descend phase. */
 240
 241                         if (b->crit_amaf && !is_pass(node_coord(node))) {
 242                                 stats_add_result(&ni->winner_owner, board_at(final_board, node_coord(ni)) == winner_color ? 1.0 : 0.0, 1);
 243                                 stats_add_result(&ni->black_owner, board_at(final_board, node_coord(ni)) == S_BLACK ? 1.0 : 0.0, 1);
 244                         }
 245                         stats_add_result(&ni->amaf, nres, 1);
 246
 247 #if 0
 248                         struct board bb; bb.size = 9+2;
 249                         fprintf(stderr, "* %s<%"PRIhash"> -> %s<%"PRIhash"> [%d/%f => %d/%f]\n",
 250                                 coord2sstr(node_coord(node), &bb), node->hash,
 251                                 coord2sstr(node_coord(ni), &bb), ni->hash,
 252                                 player_color, result, child_color, nres);
 253 #endif
 254                 }
 255
 256                 if (!is_pass(node_coord(node))) {
 257                         map->game_baselen--;
 258                 }
 259                 node = node->parent; child_color = stone_other(child_color);
 260         }
 261 }
 262
 263
 264 struct uct_policy *
 265 policy_ucb1amaf_init(struct uct *u, char *arg)
 266 {
 267         struct uct_policy *p = calloc2(1, sizeof(*p));
 268         struct ucb1_policy_amaf *b = calloc2(1, sizeof(*b));
 269         p->uct = u;
 270         p->data = b;
 271         p->choose = uctp_generic_choose;
 272         p->winner = uctp_generic_winner;
 273         p->evaluate = ucb1rave_evaluate;
 274         p->descend = ucb1rave_descend;
 275         p->update = ucb1amaf_update;
 276         p->wants_amaf = true;
 277
 278         b->explore_p = 0; // 0.02 can be also good on 19x19 with prior=eqex=40
 279         b->equiv_rave = 3000;
 280         b->fpu = INFINITY;
 281         b->check_nakade = true;
 282         b->sylvain_rave = true;
 283         b->ltree_rave = 0.75f;
 284
 285         b->crit_rave = 1.0f;
 286         b->crit_min_playouts = 2000;
 287         b->crit_negative = 1;
 288         b->crit_amaf = 0;
 289
 290         if (arg) {
 291                 char *optspec, *next = arg;
 292                 while (*next) {
 293                         optspec = next;
 294                         next += strcspn(next, ":");
 295                         if (*next) { *next++ = 0; } else { *next = 0; }
 296
 297                         char *optname = optspec;
 298                         char *optval = strchr(optspec, '=');
 299                         if (optval) *optval++ = 0;
 300
 301                         if (!strcasecmp(optname, "explore_p")) {
 302                                 b->explore_p = atof(optval);
 303                         } else if (!strcasecmp(optname, "fpu") && optval) {
 304                                 b->fpu = atof(optval);
 305                         } else if (!strcasecmp(optname, "equiv_rave") && optval) {
 306                                 b->equiv_rave = atof(optval);
 307                         } else if (!strcasecmp(optname, "sylvain_rave")) {
 308                                 b->sylvain_rave = !optval || *optval == '1';
 309                         } else if (!strcasecmp(optname, "check_nakade")) {
 310                                 b->check_nakade = !optval || *optval == '1';
 311                         } else if (!strcasecmp(optname, "ltree_rave") && optval) {
 312                                 b->ltree_rave = atof(optval);
 313                         } else if (!strcasecmp(optname, "crit_rave") && optval) {
 314                                 b->crit_rave = atof(optval);
 315                         } else if (!strcasecmp(optname, "crit_min_playouts") && optval) {
 316                                 b->crit_min_playouts = atoi(optval);
 317                         } else if (!strcasecmp(optname, "crit_negative")) {
 318                                 b->crit_negative = !optval || *optval == '1';
 319                         } else if (!strcasecmp(optname, "crit_amaf")) {
 320                                 b->crit_amaf = !optval || *optval == '1';
 321                         } else {
 322                                 fprintf(stderr, "ucb1amaf: Invalid policy argument %s or missing value\n",
 323                                         optname);
 324                                 exit(1);
 325                         }
 326                 }
 327         }
 328
 329         return p;
 330 }