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 "tactics/util.h"
  12 #include "uct/internal.h"
  13 #include "uct/tree.h"
  14 #include "uct/policy/generic.h"
  15
  16 /* This implements the UCB1 policy with an extra AMAF heuristics. */
  17
  18 struct ucb1_policy_amaf {
  19         /* This is what the Modification of UCT with Patterns in Monte Carlo Go
  20          * paper calls 'p'. Original UCB has this on 2, but this seems to
  21          * produce way too wide searches; reduce this to get deeper and
  22          * narrower readouts - try 0.2. */
  23         floating_t explore_p;
  24         /* First Play Urgency - if set to less than infinity (the MoGo paper
  25          * above reports 1.0 as the best), new branches are explored only
  26          * if none of the existing ones has higher urgency than fpu. */
  27         floating_t fpu;
  28         unsigned int equiv_rave;
  29         bool check_nakade;
  30         bool sylvain_rave;
  31         /* Coefficient of local tree values embedded in RAVE. */
  32         floating_t ltree_rave;
  33         /* Coefficient of criticality embedded in RAVE. */
  34         floating_t crit_rave;
  35         int crit_min_playouts;
  36         bool crit_negative;
  37         bool crit_negflip;
  38         bool crit_amaf;
  39         bool crit_lvalue;
  40 };
  41
  42
  43 static inline floating_t fast_sqrt(unsigned int x)
  44 {
  45         static const floating_t table[] = {
  46                 0, 1, 1.41421356237309504880, 1.73205080756887729352,
  47                 2.00000000000000000000, 2.23606797749978969640,
  48                 2.44948974278317809819, 2.64575131106459059050,
  49                 2.82842712474619009760, 3.00000000000000000000,
  50                 3.16227766016837933199, 3.31662479035539984911,
  51                 3.46410161513775458705, 3.60555127546398929311,
  52                 3.74165738677394138558, 3.87298334620741688517,
  53                 4.00000000000000000000, 4.12310562561766054982,
  54                 4.24264068711928514640, 4.35889894354067355223,
  55                 4.47213595499957939281, 4.58257569495584000658,
  56                 4.69041575982342955456, 4.79583152331271954159,
  57                 4.89897948556635619639, 5.00000000000000000000,
  58                 5.09901951359278483002, 5.19615242270663188058,
  59                 5.29150262212918118100, 5.38516480713450403125,
  60                 5.47722557505166113456, 5.56776436283002192211,
  61                 5.65685424949238019520, 5.74456264653802865985,
  62                 5.83095189484530047087, 5.91607978309961604256,
  63                 6.00000000000000000000, 6.08276253029821968899,
  64                 6.16441400296897645025, 6.24499799839839820584,
  65                 6.32455532033675866399, 6.40312423743284868648,
  66                 6.48074069840786023096, 6.55743852430200065234,
  67                 6.63324958071079969822, 6.70820393249936908922,
  68                 6.78232998312526813906, 6.85565460040104412493,
  69                 6.92820323027550917410, 7.00000000000000000000,
  70                 7.07106781186547524400, 7.14142842854284999799,
  71                 7.21110255092797858623, 7.28010988928051827109,
  72                 7.34846922834953429459, 7.41619848709566294871,
  73                 7.48331477354788277116, 7.54983443527074969723,
  74                 7.61577310586390828566, 7.68114574786860817576,
  75                 7.74596669241483377035, 7.81024967590665439412,
  76                 7.87400787401181101968, 7.93725393319377177150,
  77         };
  78         if (x < sizeof(table) / sizeof(*table)) {
  79                 return table[x];
  80         } else {
  81                 return sqrt(x);
  82         }
  83 }
  84
  85 #define URAVE_DEBUG if (0)
  86 static floating_t inline
  87 ucb1rave_evaluate(struct uct_policy *p, struct tree *tree, struct uct_descent *descent, int parity)
  88 {
  89         struct ucb1_policy_amaf *b = p->data;
  90         struct tree_node *node = descent->node;
  91         struct tree_node *lnode = descent->lnode;
  92
  93         struct move_stats n = node->u, r = node->amaf;
  94         if (p->uct->amaf_prior) {
  95                 stats_merge(&r, &node->prior);
  96         } else {
  97                 stats_merge(&n, &node->prior);
  98         }
  99
 100         /* Local tree heuristics. */
 101         assert(!lnode || lnode->parent);
 102         if (p->uct->local_tree && b->ltree_rave > 0 && lnode
 103             && (p->uct->local_tree_rootchoose || lnode->parent->parent)) {
 104                 struct move_stats l = lnode->u;
 105                 l.playouts = ((floating_t) l.playouts) * b->ltree_rave / LTREE_PLAYOUTS_MULTIPLIER;
 106                 URAVE_DEBUG fprintf(stderr, "[ltree] adding [%s] %f%%%d to [%s] RAVE %f%%%d\n",
 107                         coord2sstr(node_coord(lnode), tree->board), l.value, l.playouts,
 108                         coord2sstr(node_coord(node), tree->board), r.value, r.playouts);
 109                 stats_merge(&r, &l);
 110         }
 111
 112         /* Criticality heuristics. */
 113         if (b->crit_rave > 0 && node->u.playouts > b->crit_min_playouts) {
 114                 floating_t crit = tree_node_criticality(tree, node);
 115                 if (b->crit_negative || crit > 0) {
 116                         floating_t val = 1.0f;
 117                         if (b->crit_negflip && crit < 0) {
 118                                 val = 0;
 119                                 crit = -crit;
 120                         }
 121                         struct move_stats c = {
 122                                 .value = tree_node_get_value(tree, parity, val),
 123                                 .playouts = crit * r.playouts * b->crit_rave
 124                         };
 125                         URAVE_DEBUG fprintf(stderr, "[crit] adding %f%%%d to [%s] RAVE %f%%%d\n",
 126                                 c.value, c.playouts,
 127                                 coord2sstr(node_coord(node), tree->board), r.value, r.playouts);
 128                         stats_merge(&r, &c);
 129                 }
 130         }
 131
 132
 133         floating_t value = 0;
 134         if (n.playouts) {
 135                 if (r.playouts) {
 136                         /* At the beginning, beta is at 1 and RAVE is used.
 137                          * At b->equiv_rate, beta is at 1/3 and gets steeper on. */
 138                         floating_t beta;
 139                         if (b->sylvain_rave) {
 140                                 beta = (floating_t) r.playouts / (r.playouts + n.playouts
 141                                         + (floating_t) n.playouts * r.playouts / b->equiv_rave);
 142                         } else {
 143                                 /* XXX: This can be cached in descend; but we don't use this by default. */
 144                                 beta = sqrt(b->equiv_rave / (3 * node->parent->u.playouts + b->equiv_rave));
 145                         }
 146
 147                         value = beta * r.value + (1.f - beta) * n.value;
 148                         URAVE_DEBUG fprintf(stderr, "\t%s value = %f * %f + (1 - %f) * %f (prior %f)\n",
 149                                 coord2sstr(node_coord(node), tree->board), beta, r.value, beta, n.value, node->prior.value);
 150                 } else {
 151                         value = n.value;
 152                         URAVE_DEBUG fprintf(stderr, "\t%s value = %f (prior %f)\n",
 153                                 coord2sstr(node_coord(node), tree->board), n.value, node->prior.value);
 154                 }
 155         } else if (r.playouts) {
 156                 value = r.value;
 157                 URAVE_DEBUG fprintf(stderr, "\t%s value = rave %f (prior %f)\n",
 158                         coord2sstr(node_coord(node), tree->board), r.value, node->prior.value);
 159         }
 160         descent->value.playouts = r.playouts + n.playouts;
 161         descent->value.value = value;
 162         return tree_node_get_value(tree, parity, value);
 163 }
 164
 165 void
 166 ucb1rave_descend(struct uct_policy *p, struct tree *tree, struct uct_descent *descent, int parity, bool allow_pass)
 167 {
 168         struct ucb1_policy_amaf *b = p->data;
 169         floating_t nconf = 1.f;
 170         if (b->explore_p > 0)
 171                 nconf = sqrt(log(descent->node->u.playouts + descent->node->prior.playouts));
 172
 173         uctd_try_node_children(tree, descent, allow_pass, parity, p->uct->tenuki_d, di, urgency) {
 174                 struct tree_node *ni = di.node;
 175                 urgency = ucb1rave_evaluate(p, tree, &di, parity);
 176
 177                 if (ni->u.playouts > 0 && b->explore_p > 0) {
 178                         urgency += b->explore_p * nconf / fast_sqrt(ni->u.playouts);
 179
 180                 } else if (ni->u.playouts + ni->amaf.playouts + ni->prior.playouts == 0) {
 181                         /* assert(!u->even_eqex); */
 182                         urgency = b->fpu;
 183                 }
 184         } uctd_set_best_child(di, urgency);
 185
 186         uctd_get_best_child(descent);
 187 }
 188
 189
 190 void
 191 ucb1amaf_update(struct uct_policy *p, struct tree *tree, struct tree_node *node,
 192                 enum stone node_color, enum stone player_color,
 193                 struct playout_amafmap *map, struct board *final_board,
 194                 floating_t result)
 195 {
 196         struct ucb1_policy_amaf *b = p->data;
 197         enum stone winner_color = result > 0.5 ? S_BLACK : S_WHITE;
 198         enum stone child_color = stone_other(node_color);
 199
 200 #if 0
 201         struct board bb; bb.size = 9+2;
 202         for (struct tree_node *ni = node; ni; ni = ni->parent)
 203                 fprintf(stderr, "%s ", coord2sstr(node_coord(ni), &bb));
 204         fprintf(stderr, "[color %d] update result %d (color %d)\n",
 205                         node_color, result, player_color);
 206 #endif
 207
 208         while (node) {
 209                 if (node->parent == NULL)
 210                         assert(tree->root_color == stone_other(child_color));
 211
 212                 if (!b->crit_amaf && !is_pass(node_coord(node))) {
 213                         stats_add_result(&node->winner_owner, board_local_value(b->crit_lvalue, final_board, node_coord(node), winner_color), 1);
 214                         stats_add_result(&node->black_owner, board_local_value(b->crit_lvalue, final_board, node_coord(node), S_BLACK), 1);
 215                 }
 216                 stats_add_result(&node->u, result, 1);
 217                 if (!is_pass(node_coord(node)) && amaf_nakade(map->map[node_coord(node)]))
 218                         amaf_op(map->map[node_coord(node)], -);
 219
 220                 /* This loop ignores symmetry considerations, but they should
 221                  * matter only at a point when AMAF doesn't help much. */
 222                 assert(map->game_baselen >= 0);
 223                 for (struct tree_node *ni = node->children; ni; ni = ni->sibling) {
 224                         enum stone amaf_color = map->map[node_coord(ni)];
 225                         assert(amaf_color != S_OFFBOARD);
 226                         if (amaf_color == S_NONE)
 227                                 continue;
 228                         if (amaf_nakade(map->map[node_coord(ni)])) {
 229                                 if (!b->check_nakade)
 230                                         continue;
 231                                 unsigned int i;
 232                                 for (i = map->game_baselen; i < map->gamelen; i++)
 233                                         if (map->game[i].coord == node_coord(ni)
 234                                             && map->game[i].color == child_color)
 235                                                 break;
 236                                 if (i == map->gamelen)
 237                                         continue;
 238                                 amaf_color = child_color;
 239                         }
 240
 241                         floating_t nres = result;
 242                         if (amaf_color != child_color) {
 243                                 continue;
 244                         }
 245                         /* For child_color != player_color, we still want
 246                          * to record the result unmodified; in that case,
 247                          * we will correctly negate them at the descend phase. */
 248
 249                         if (b->crit_amaf && !is_pass(node_coord(node))) {
 250                                 stats_add_result(&ni->winner_owner, board_local_value(b->crit_lvalue, final_board, node_coord(ni), winner_color), 1);
 251                                 stats_add_result(&ni->black_owner, board_local_value(b->crit_lvalue, final_board, node_coord(ni), S_BLACK), 1);
 252                         }
 253                         stats_add_result(&ni->amaf, nres, 1);
 254
 255 #if 0
 256                         struct board bb; bb.size = 9+2;
 257                         fprintf(stderr, "* %s<%"PRIhash"> -> %s<%"PRIhash"> [%d/%f => %d/%f]\n",
 258                                 coord2sstr(node_coord(node), &bb), node->hash,
 259                                 coord2sstr(node_coord(ni), &bb), ni->hash,
 260                                 player_color, result, child_color, nres);
 261 #endif
 262                 }
 263
 264                 if (!is_pass(node_coord(node))) {
 265                         map->game_baselen--;
 266                 }
 267                 node = node->parent; child_color = stone_other(child_color);
 268         }
 269 }
 270
 271
 272 struct uct_policy *
 273 policy_ucb1amaf_init(struct uct *u, char *arg)
 274 {
 275         struct uct_policy *p = calloc2(1, sizeof(*p));
 276         struct ucb1_policy_amaf *b = calloc2(1, sizeof(*b));
 277         p->uct = u;
 278         p->data = b;
 279         p->choose = uctp_generic_choose;
 280         p->winner = uctp_generic_winner;
 281         p->evaluate = ucb1rave_evaluate;
 282         p->descend = ucb1rave_descend;
 283         p->update = ucb1amaf_update;
 284         p->wants_amaf = true;
 285
 286         b->explore_p = 0; // 0.02 can be also good on 19x19 with prior=eqex=40
 287         b->equiv_rave = 3000;
 288         b->fpu = INFINITY;
 289         b->check_nakade = true;
 290         b->sylvain_rave = true;
 291         b->ltree_rave = 0.75f;
 292
 293         b->crit_rave = 1.0f;
 294         b->crit_min_playouts = 2000;
 295         b->crit_negative = 1;
 296         b->crit_amaf = 0;
 297
 298         if (arg) {
 299                 char *optspec, *next = arg;
 300                 while (*next) {
 301                         optspec = next;
 302                         next += strcspn(next, ":");
 303                         if (*next) { *next++ = 0; } else { *next = 0; }
 304
 305                         char *optname = optspec;
 306                         char *optval = strchr(optspec, '=');
 307                         if (optval) *optval++ = 0;
 308
 309                         if (!strcasecmp(optname, "explore_p")) {
 310                                 b->explore_p = atof(optval);
 311                         } else if (!strcasecmp(optname, "fpu") && optval) {
 312                                 b->fpu = atof(optval);
 313                         } else if (!strcasecmp(optname, "equiv_rave") && optval) {
 314                                 b->equiv_rave = atof(optval);
 315                         } else if (!strcasecmp(optname, "sylvain_rave")) {
 316                                 b->sylvain_rave = !optval || *optval == '1';
 317                         } else if (!strcasecmp(optname, "check_nakade")) {
 318                                 b->check_nakade = !optval || *optval == '1';
 319                         } else if (!strcasecmp(optname, "ltree_rave") && optval) {
 320                                 b->ltree_rave = atof(optval);
 321                         } else if (!strcasecmp(optname, "crit_rave") && optval) {
 322                                 b->crit_rave = atof(optval);
 323                         } else if (!strcasecmp(optname, "crit_min_playouts") && optval) {
 324                                 b->crit_min_playouts = atoi(optval);
 325                         } else if (!strcasecmp(optname, "crit_negative")) {
 326                                 b->crit_negative = !optval || *optval == '1';
 327                         } else if (!strcasecmp(optname, "crit_negflip")) {
 328                                 b->crit_negflip = !optval || *optval == '1';
 329                         } else if (!strcasecmp(optname, "crit_amaf")) {
 330                                 b->crit_amaf = !optval || *optval == '1';
 331                         } else if (!strcasecmp(optname, "crit_lvalue")) {
 332                                 b->crit_lvalue = !optval || *optval == '1';
 333                         } else {
 334                                 fprintf(stderr, "ucb1amaf: Invalid policy argument %s or missing value\n",
 335                                         optname);
 336                                 exit(1);
 337                         }
 338                 }
 339         }
 340
 341         return p;
 342 }