uct/dynkomi.c

   1 #define DEBUG
   2 #include <assert.h>
   3 #include <math.h>
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include <string.h>
   7
   8 #include "board.h"
   9 #include "debug.h"
  10 #include "tactics/util.h"
  11 #include "uct/dynkomi.h"
  12 #include "uct/internal.h"
  13 #include "uct/tree.h"
  14
  15
  16 static void
  17 generic_done(struct uct_dynkomi *d)
  18 {
  19         if (d->data) free(d->data);
  20         free(d);
  21 }
  22
  23
  24 /* NONE dynkomi strategy - never fiddle with komi values. */
  25
  26 struct uct_dynkomi *
  27 uct_dynkomi_init_none(struct uct *u, char *arg, struct board *b)
  28 {
  29         struct uct_dynkomi *d = calloc2(1, sizeof(*d));
  30         d->uct = u;
  31         d->permove = NULL;
  32         d->persim = NULL;
  33         d->done = generic_done;
  34         d->data = NULL;
  35
  36         if (arg) {
  37                 fprintf(stderr, "uct: Dynkomi method none accepts no arguments\n");
  38                 exit(1);
  39         }
  40
  41         return d;
  42 }
  43
  44
  45 /* LINEAR dynkomi strategy - Linearly Decreasing Handicap Compensation. */
  46 /* At move 0, we impose extra komi of handicap_count*handicap_value, then
  47  * we linearly decrease this extra komi throughout the game down to 0
  48  * at @moves moves. Towards the end of the game the linear compensation
  49  * becomes zero but we increase the extra komi when winning big. This reduces
  50  * the number of point-wasting moves and makes the game more enjoyable for humans. */
  51
  52 struct dynkomi_linear {
  53         int handicap_value[S_MAX];
  54         int moves[S_MAX];
  55         bool rootbased;
  56         /* Increase the extra komi if my win ratio  > green_zone but always
  57          * keep extra_komi <= komi_ratchet. komi_ratchet starts infinite but decreases
  58          * when we give too much extra komi and this puts us back < orange_zone.
  59          * This is meant only to increase the territory margin when playing against
  60          * weaker opponents. We never take negative komi when losing. The ratchet helps
  61          * avoiding oscillations and keeping us above orange_zone.
  62          * To disable the adaptive phase, set green_zone=2. */
  63         floating_t komi_ratchet;
  64         floating_t green_zone;
  65         floating_t orange_zone;
  66         floating_t drop_step;
  67 };
  68
  69 static floating_t
  70 linear_permove(struct uct_dynkomi *d, struct board *b, struct tree *tree)
  71 {
  72         struct dynkomi_linear *l = d->data;
  73         enum stone color = d->uct->pondering ? tree->root_color : stone_other(tree->root_color);
  74         int lmoves = l->moves[color];
  75         floating_t extra_komi;
  76
  77         if (b->moves < lmoves) {
  78                 floating_t base_komi = board_effective_handicap(b, l->handicap_value[color]);
  79                 extra_komi = base_komi * (lmoves - b->moves) / lmoves;
  80                 return extra_komi;
  81         } else {
  82                 extra_komi = floor(tree->extra_komi);
  83         }
  84
  85         /* Do not take decisions on unstable value. */
  86         if (tree->root->u.playouts < GJ_MINGAMES) return extra_komi;
  87
  88         floating_t my_value = tree_node_get_value(tree, 1, tree->root->u.value);
  89         /*  We normalize komi as in komi_by_value(), > 0 when winning. */
  90         extra_komi = komi_by_color(extra_komi, color);
  91         if (extra_komi < 0 && DEBUGL(3))
  92                 fprintf(stderr, "XXX: extra_komi %.3f < 0 (color %s tree ek %.3f)\n", extra_komi, stone2str(color), tree->extra_komi);
  93         // assert(extra_komi >= 0);
  94         floating_t orig_komi = extra_komi;
  95
  96         if (my_value < 0.5 && l->komi_ratchet > 0 && l->komi_ratchet != INFINITY) {
  97                 if (DEBUGL(0))
  98                         fprintf(stderr, "losing %f extra komi %.1f ratchet %.1f -> 0\n",
  99                                 my_value, extra_komi, l->komi_ratchet);
 100                 /* Disable dynkomi completely, too dangerous in this game. */
 101                 extra_komi = l->komi_ratchet = 0;
 102
 103         } else if (my_value < l->orange_zone && extra_komi > 0) {
 104                 extra_komi = l->komi_ratchet  = fmax(extra_komi - l->drop_step, 0.0);
 105                 if (extra_komi != orig_komi && DEBUGL(3))
 106                         fprintf(stderr, "dropping to %f, extra komi %.1f -> ratchet %.1f\n",
 107                                 my_value, orig_komi, extra_komi);
 108
 109         } else if (my_value > l->green_zone && extra_komi + 1 <= l->komi_ratchet) {
 110                 extra_komi += 1;
 111                 if (extra_komi != orig_komi && DEBUGL(3))
 112                         fprintf(stderr, "winning %f extra_komi %.1f -> %.1f, ratchet %.1f\n",
 113                                 my_value, orig_komi, extra_komi, l->komi_ratchet);
 114         }
 115         return komi_by_color(extra_komi, color);
 116 }
 117
 118 static floating_t
 119 linear_persim(struct uct_dynkomi *d, struct board *b, struct tree *tree, struct tree_node *node)
 120 {
 121         struct dynkomi_linear *l = d->data;
 122         if (l->rootbased)
 123                 return tree->extra_komi;
 124         /* We don't reuse computed value from tree->extra_komi,
 125          * since we want to use value correct for this node depth.
 126          * This also means the values will stay correct after
 127          * node promotion. */
 128         return linear_permove(d, b, tree);
 129 }
 130
 131 struct uct_dynkomi *
 132 uct_dynkomi_init_linear(struct uct *u, char *arg, struct board *b)
 133 {
 134         struct uct_dynkomi *d = calloc2(1, sizeof(*d));
 135         d->uct = u;
 136         d->permove = linear_permove;
 137         d->persim = linear_persim;
 138         d->done = generic_done;
 139
 140         struct dynkomi_linear *l = calloc2(1, sizeof(*l));
 141         d->data = l;
 142
 143         /* Force white to feel behind and try harder, but not to the
 144          * point of resigning immediately in high handicap games.
 145          * By move 100 white should still be behind but should have
 146          * caught up enough to avoid resigning. */
 147         int moves = board_large(b) ? 100 : 50;
 148         if (!board_small(b)) {
 149                 l->moves[S_BLACK] = moves;
 150                 l->moves[S_WHITE] = moves;
 151         }
 152
 153         /* The real value of one stone is twice the komi so about 15 points.
 154          * But use a lower value to avoid being too pessimistic as black
 155          * or too optimistic as white. */
 156         l->handicap_value[S_BLACK] = 8;
 157         l->handicap_value[S_WHITE] = 1;
 158
 159         l->komi_ratchet = INFINITY;
 160         l->green_zone = 0.85;
 161         l->orange_zone = 0.8;
 162         l->drop_step = 4.0;
 163
 164         if (arg) {
 165                 char *optspec, *next = arg;
 166                 while (*next) {
 167                         optspec = next;
 168                         next += strcspn(next, ":");
 169                         if (*next) { *next++ = 0; } else { *next = 0; }
 170
 171                         char *optname = optspec;
 172                         char *optval = strchr(optspec, '=');
 173                         if (optval) *optval++ = 0;
 174
 175                         if (!strcasecmp(optname, "moves") && optval) {
 176                                 /* Dynamic komi in handicap game; linearly
 177                                  * decreases to basic settings until move
 178                                  * #optval. moves=blackmoves%whitemoves */
 179                                 for (int i = S_BLACK; *optval && i <= S_WHITE; i++) {
 180                                         l->moves[i] = atoi(optval);
 181                                         optval += strcspn(optval, "%");
 182                                         if (*optval) optval++;
 183                                 }
 184                         } else if (!strcasecmp(optname, "handicap_value") && optval) {
 185                                 /* Point value of single handicap stone,
 186                                  * for dynkomi computation. */
 187                                 for (int i = S_BLACK; *optval && i <= S_WHITE; i++) {
 188                                         l->handicap_value[i] = atoi(optval);
 189                                         optval += strcspn(optval, "%");
 190                                         if (*optval) optval++;
 191                                 }
 192                         } else if (!strcasecmp(optname, "rootbased")) {
 193                                 /* If set, the extra komi applied will be
 194                                  * the same for all simulations within a move,
 195                                  * instead of being same for all simulations
 196                                  * within the tree node. */
 197                                 l->rootbased = !optval || atoi(optval);
 198                         } else if (!strcasecmp(optname, "green_zone") && optval) {
 199                                 /* Increase komi when win ratio is above green_zone */
 200                                 l->green_zone = atof(optval);
 201                         } else if (!strcasecmp(optname, "orange_zone") && optval) {
 202                                 /* Decrease komi when > 0 and win ratio is below orange_zone */
 203                                 l->orange_zone = atof(optval);
 204                         } else if (!strcasecmp(optname, "drop_step") && optval) {
 205                                 /* Decrease komi by drop_step points */
 206                                 l->drop_step = atof(optval);
 207                         } else {
 208                                 fprintf(stderr, "uct: Invalid dynkomi argument %s or missing value\n", optname);
 209                                 exit(1);
 210                         }
 211                 }
 212         }
 213
 214         return d;
 215 }
 216
 217
 218 /* ADAPTIVE dynkomi strategy - Adaptive Situational Compensation */
 219 /* We adapt the komi based on current situation:
 220  * (i) score-based: We maintain the average score outcome of our
 221  * games and adjust the komi by a fractional step towards the expected
 222  * score;
 223  * (ii) value-based: While winrate is above given threshold, adjust
 224  * the komi by a fixed step in the appropriate direction.
 225  * These adjustments can be
 226  * (a) Move-stepped, new extra komi value is always set only at the
 227  * beginning of the tree search for next move;
 228  * (b) Continuous, new extra komi value is periodically re-determined
 229  * and adjusted throughout a single tree search. */
 230
 231 struct dynkomi_adaptive {
 232         /* Do not take measured average score into regard for
 233          * first @lead_moves - the variance is just too much.
 234          * (Instead, we consider the handicap-based komi provided
 235          * by linear dynkomi.) */
 236         int lead_moves;
 237         /* Maximum komi to pretend the opponent to give. */
 238         floating_t max_losing_komi;
 239         /* Game portion at which losing komi is not allowed anymore. */
 240         floating_t losing_komi_stop;
 241         /* Turn off dynkomi at the (perceived) closing of the game
 242          * (last few moves). */
 243         bool no_komi_at_game_end;
 244         /* Alternative game portion determination. */
 245         bool adapt_aport;
 246         floating_t (*indicator)(struct uct_dynkomi *d, struct board *b, struct tree *tree, enum stone color);
 247
 248         /* Value-based adaptation. */
 249         floating_t zone_red, zone_green;
 250         int score_step;
 251         floating_t score_step_byavg; // use portion of average score as increment
 252         bool use_komi_ratchet;
 253         bool losing_komi_ratchet; // ratchet even losing komi
 254         int komi_ratchet_maxage;
 255         // runtime, not configuration:
 256         int komi_ratchet_age;
 257         floating_t komi_ratchet;
 258
 259         /* Score-based adaptation. */
 260         floating_t (*adapter)(struct uct_dynkomi *d, struct board *b);
 261         floating_t adapt_base; // [0,1)
 262         /* Sigmoid adaptation rate parameter; see below for details. */
 263         floating_t adapt_phase; // [0,1]
 264         floating_t adapt_rate; // [1,infty)
 265         /* Linear adaptation rate parameter. */
 266         int adapt_moves;
 267         floating_t adapt_dir; // [-1,1]
 268 };
 269 #define TRUSTWORTHY_KOMI_PLAYOUTS 200
 270
 271 static floating_t
 272 board_game_portion(struct dynkomi_adaptive *a, struct board *b)
 273 {
 274         if (!a->adapt_aport) {
 275                 int total_moves = b->moves + 2 * board_estimated_moves_left(b);
 276                 return (floating_t) b->moves / total_moves;
 277         } else {
 278                 int brsize = board_size(b) - 2;
 279                 return 1.0 - (floating_t) b->flen / (brsize * brsize);
 280         }
 281 }
 282
 283 static floating_t
 284 adapter_sigmoid(struct uct_dynkomi *d, struct board *b)
 285 {
 286         struct dynkomi_adaptive *a = d->data;
 287         /* Figure out how much to adjust the komi based on the game
 288          * stage. The adaptation rate is 0 at the beginning,
 289          * at game stage a->adapt_phase crosses though 0.5 and
 290          * approaches 1 at the game end; the slope is controlled
 291          * by a->adapt_rate. */
 292         floating_t game_portion = board_game_portion(a, b);
 293         floating_t l = game_portion - a->adapt_phase;
 294         return 1.0 / (1.0 + exp(-a->adapt_rate * l));
 295 }
 296
 297 static floating_t
 298 adapter_linear(struct uct_dynkomi *d, struct board *b)
 299 {
 300         struct dynkomi_adaptive *a = d->data;
 301         /* Figure out how much to adjust the komi based on the game
 302          * stage. We just linearly increase/decrease the adaptation
 303          * rate for first N moves. */
 304         if (b->moves > a->adapt_moves)
 305                 return 0;
 306         if (a->adapt_dir < 0)
 307                 return 1 - (- a->adapt_dir) * b->moves / a->adapt_moves;
 308         else
 309                 return a->adapt_dir * b->moves / a->adapt_moves;
 310 }
 311
 312 static floating_t
 313 komi_by_score(struct uct_dynkomi *d, struct board *b, struct tree *tree, enum stone color)
 314 {
 315         struct dynkomi_adaptive *a = d->data;
 316         if (d->score.playouts < TRUSTWORTHY_KOMI_PLAYOUTS)
 317                 return tree->extra_komi;
 318
 319         struct move_stats score = d->score;
 320         /* Almost-reset tree->score to gather fresh stats. */
 321         d->score.playouts = 1;
 322
 323         /* Look at average score and push extra_komi in that direction. */
 324         floating_t p = a->adapter(d, b);
 325         p = a->adapt_base + p * (1 - a->adapt_base);
 326         if (p > 0.9) p = 0.9; // don't get too eager!
 327         floating_t extra_komi = tree->extra_komi + p * score.value;
 328         if (DEBUGL(3))
 329                 fprintf(stderr, "mC += %f * %f\n", p, score.value);
 330         return extra_komi;
 331 }
 332
 333 static floating_t
 334 komi_by_value(struct uct_dynkomi *d, struct board *b, struct tree *tree, enum stone color)
 335 {
 336         struct dynkomi_adaptive *a = d->data;
 337         if (d->value.playouts < TRUSTWORTHY_KOMI_PLAYOUTS)
 338                 return tree->extra_komi;
 339
 340         struct move_stats value = d->value;
 341         /* Almost-reset tree->value to gather fresh stats. */
 342         d->value.playouts = 1;
 343         /* Correct color POV. */
 344         if (color == S_WHITE)
 345                 value.value = 1 - value.value;
 346
 347         /* We have three "value zones":
 348          * red zone | yellow zone | green zone
 349          *        ~45%           ~60%
 350          * red zone: reduce komi
 351          * yellow zone: do not touch komi
 352          * green zone: enlage komi.
 353          *
 354          * Also, at some point komi will be tuned in such way
 355          * that it will be in green zone but increasing it will
 356          * be unfeasible. Thus, we have a _ratchet_ - we will
 357          * remember the last komi that has put us into the
 358          * red zone, and not use it or go over it. We use the
 359          * ratchet only when giving extra komi, we always want
 360          * to try to reduce extra komi we take.
 361          *
 362          * TODO: Make the ratchet expire after a while. */
 363
 364         /* We use komi_by_color() first to normalize komi
 365          * additions/subtractions, then apply it again on
 366          * return value to restore original komi parity. */
 367         /* Positive extra_komi means that we are _giving_
 368          * komi (winning), negative extra_komi is _taking_
 369          * komi (losing). */
 370         floating_t extra_komi = komi_by_color(tree->extra_komi, color);
 371         int score_step_red = -a->score_step;
 372         int score_step_green = a->score_step;
 373
 374         if (a->score_step_byavg != 0) {
 375                 struct move_stats score = d->score;
 376                 /* Almost-reset tree->score to gather fresh stats. */
 377                 d->score.playouts = 1;
 378                 /* Correct color POV. */
 379                 if (color == S_WHITE)
 380                         score.value = - score.value;
 381                 if (score.value > 0)
 382                         score_step_green = round(score.value * a->score_step_byavg);
 383                 else
 384                         score_step_red = round(-score.value * a->score_step_byavg);
 385                 if (score_step_green < 0 || score_step_red > 0) {
 386                         /* The steps are in bad direction - keep still. */
 387                         return komi_by_color(extra_komi, color);
 388                 }
 389         }
 390
 391         /* Wear out the ratchet. */
 392         if (a->use_komi_ratchet && a->komi_ratchet_maxage > 0) {
 393                 a->komi_ratchet_age += value.playouts;
 394                 if (a->komi_ratchet_age > a->komi_ratchet_maxage) {
 395                         a->komi_ratchet = 1000;
 396                         a->komi_ratchet_age = 0;
 397                 }
 398         }
 399
 400         if (value.value < a->zone_red) {
 401                 /* Red zone. Take extra komi. */
 402                 if (DEBUGL(3))
 403                         fprintf(stderr, "[red] %f, step %d | komi ratchet %f age %d/%d -> %f\n",
 404                                 value.value, score_step_red, a->komi_ratchet, a->komi_ratchet_age, a->komi_ratchet_maxage, extra_komi);
 405                 if (a->losing_komi_ratchet || extra_komi > 0) {
 406                         a->komi_ratchet = extra_komi;
 407                         a->komi_ratchet_age = 0;
 408                 }
 409                 extra_komi += score_step_red;
 410                 return komi_by_color(extra_komi, color);
 411
 412         } else if (value.value < a->zone_green) {
 413                 /* Yellow zone, do nothing. */
 414                 return komi_by_color(extra_komi, color);
 415
 416         } else {
 417                 /* Green zone. Give extra komi. */
 418                 if (DEBUGL(3))
 419                         fprintf(stderr, "[green] %f, step %d | komi ratchet %f age %d/%d\n",
 420                                 value.value, score_step_green, a->komi_ratchet, a->komi_ratchet_age, a->komi_ratchet_maxage);
 421                 extra_komi += score_step_green;
 422                 if (a->use_komi_ratchet && extra_komi >= a->komi_ratchet)
 423                         extra_komi = a->komi_ratchet - 1;
 424                 return komi_by_color(extra_komi, color);
 425         }
 426 }
 427
 428 static floating_t
 429 bounded_komi(struct dynkomi_adaptive *a, struct board *b,
 430              enum stone color, floating_t komi, floating_t max_losing_komi)
 431 {
 432         /* At the end of game, disallow losing komi. */
 433         if (komi_by_color(komi, color) < 0
 434             && board_game_portion(a, b) > a->losing_komi_stop)
 435                 return 0;
 436
 437         /* Get lower bound on komi we take so that we don't underperform
 438          * too much. */
 439         floating_t min_komi = komi_by_color(- max_losing_komi, color);
 440
 441         if (komi_by_color(komi - min_komi, color) > 0)
 442                 return komi;
 443         else
 444                 return min_komi;
 445 }
 446
 447 static floating_t
 448 adaptive_permove(struct uct_dynkomi *d, struct board *b, struct tree *tree)
 449 {
 450         struct dynkomi_adaptive *a = d->data;
 451         enum stone color = stone_other(tree->root_color);
 452
 453         /* We do not use extra komi at the game end - we are not
 454          * to fool ourselves at this point. */
 455         if (a->no_komi_at_game_end && board_estimated_moves_left(b) <= MIN_MOVES_LEFT) {
 456                 tree->use_extra_komi = false;
 457                 return 0;
 458         }
 459
 460         if (DEBUGL(4))
 461                 fprintf(stderr, "m %d/%d ekomi %f permove %f/%d\n",
 462                         b->moves, a->lead_moves, tree->extra_komi,
 463                         d->score.value, d->score.playouts);
 464
 465         if (b->moves <= a->lead_moves)
 466                 return bounded_komi(a, b, color,
 467                                     board_effective_handicap(b, 7 /* XXX */),
 468                                     a->max_losing_komi);
 469
 470         floating_t komi = a->indicator(d, b, tree, color);
 471         if (DEBUGL(4))
 472                 fprintf(stderr, "dynkomi: %f -> %f\n", tree->extra_komi, komi);
 473         return bounded_komi(a, b, color, komi, a->max_losing_komi);
 474 }
 475
 476 static floating_t
 477 adaptive_persim(struct uct_dynkomi *d, struct board *b, struct tree *tree, struct tree_node *node)
 478 {
 479         return tree->extra_komi;
 480 }
 481
 482 struct uct_dynkomi *
 483 uct_dynkomi_init_adaptive(struct uct *u, char *arg, struct board *b)
 484 {
 485         struct uct_dynkomi *d = calloc2(1, sizeof(*d));
 486         d->uct = u;
 487         d->permove = adaptive_permove;
 488         d->persim = adaptive_persim;
 489         d->done = generic_done;
 490
 491         struct dynkomi_adaptive *a = calloc2(1, sizeof(*a));
 492         d->data = a;
 493
 494         a->lead_moves = board_large(b) ? 20 : 4; // XXX
 495         a->max_losing_komi = 30;
 496         a->losing_komi_stop = 1.0f;
 497         a->no_komi_at_game_end = true;
 498         a->indicator = komi_by_value;
 499
 500         a->adapter = adapter_sigmoid;
 501         a->adapt_rate = -18;
 502         a->adapt_phase = 0.65;
 503         a->adapt_moves = 200;
 504         a->adapt_dir = -0.5;
 505
 506         a->zone_red = 0.45;
 507         a->zone_green = 0.50;
 508         a->score_step = 1;
 509         a->use_komi_ratchet = true;
 510         a->komi_ratchet_maxage = 0;
 511         a->komi_ratchet = 1000;
 512
 513         if (arg) {
 514                 char *optspec, *next = arg;
 515                 while (*next) {
 516                         optspec = next;
 517                         next += strcspn(next, ":");
 518                         if (*next) { *next++ = 0; } else { *next = 0; }
 519
 520                         char *optname = optspec;
 521                         char *optval = strchr(optspec, '=');
 522                         if (optval) *optval++ = 0;
 523
 524                         if (!strcasecmp(optname, "lead_moves") && optval) {
 525                                 /* Do not adjust komi adaptively for first
 526                                  * N moves. */
 527                                 a->lead_moves = atoi(optval);
 528                         } else if (!strcasecmp(optname, "max_losing_komi") && optval) {
 529                                 a->max_losing_komi = atof(optval);
 530                         } else if (!strcasecmp(optname, "losing_komi_stop") && optval) {
 531                                 a->losing_komi_stop = atof(optval);
 532                         } else if (!strcasecmp(optname, "no_komi_at_game_end")) {
 533                                 a->no_komi_at_game_end = !optval || atoi(optval);
 534                         } else if (!strcasecmp(optname, "indicator")) {
 535                                 /* Adaptatation indicator - how to decide
 536                                  * the adaptation rate and direction. */
 537                                 if (!strcasecmp(optval, "value")) {
 538                                         /* Winrate w/ komi so far. */
 539                                         a->indicator = komi_by_value;
 540                                 } else if (!strcasecmp(optval, "score")) {
 541                                         /* Expected score w/ current komi. */
 542                                         a->indicator = komi_by_score;
 543                                 } else {
 544                                         fprintf(stderr, "UCT: Invalid indicator %s\n", optval);
 545                                         exit(1);
 546                                 }
 547
 548                                 /* value indicator settings */
 549                         } else if (!strcasecmp(optname, "zone_red") && optval) {
 550                                 a->zone_red = atof(optval);
 551                         } else if (!strcasecmp(optname, "zone_green") && optval) {
 552                                 a->zone_green = atof(optval);
 553                         } else if (!strcasecmp(optname, "score_step") && optval) {
 554                                 a->score_step = atoi(optval);
 555                         } else if (!strcasecmp(optname, "score_step_byavg") && optval) {
 556                                 a->score_step_byavg = atof(optval);
 557                         } else if (!strcasecmp(optname, "use_komi_ratchet")) {
 558                                 a->use_komi_ratchet = !optval || atoi(optval);
 559                         } else if (!strcasecmp(optname, "losing_komi_ratchet")) {
 560                                 a->losing_komi_ratchet = !optval || atoi(optval);
 561                         } else if (!strcasecmp(optname, "komi_ratchet_age") && optval) {
 562                                 a->komi_ratchet_maxage = atoi(optval);
 563
 564                                 /* score indicator settings */
 565                         } else if (!strcasecmp(optname, "adapter") && optval) {
 566                                 /* Adaptatation method. */
 567                                 if (!strcasecmp(optval, "sigmoid")) {
 568                                         a->adapter = adapter_sigmoid;
 569                                 } else if (!strcasecmp(optval, "linear")) {
 570                                         a->adapter = adapter_linear;
 571                                 } else {
 572                                         fprintf(stderr, "UCT: Invalid adapter %s\n", optval);
 573                                         exit(1);
 574                                 }
 575                         } else if (!strcasecmp(optname, "adapt_base") && optval) {
 576                                 /* Adaptation base rate; see above. */
 577                                 a->adapt_base = atof(optval);
 578                         } else if (!strcasecmp(optname, "adapt_rate") && optval) {
 579                                 /* Adaptation slope; see above. */
 580                                 a->adapt_rate = atof(optval);
 581                         } else if (!strcasecmp(optname, "adapt_phase") && optval) {
 582                                 /* Adaptation phase shift; see above. */
 583                                 a->adapt_phase = atof(optval);
 584                         } else if (!strcasecmp(optname, "adapt_moves") && optval) {
 585                                 /* Adaptation move amount; see above. */
 586                                 a->adapt_moves = atoi(optval);
 587                         } else if (!strcasecmp(optname, "adapt_aport")) {
 588                                 a->adapt_aport = !optval || atoi(optval);
 589                         } else if (!strcasecmp(optname, "adapt_dir") && optval) {
 590                                 /* Adaptation direction vector; see above. */
 591                                 a->adapt_dir = atof(optval);
 592
 593                         } else {
 594                                 fprintf(stderr, "uct: Invalid dynkomi argument %s or missing value\n", optname);
 595                                 exit(1);
 596                         }
 597                 }
 598         }
 599
 600         return d;
 601 }