/**
* Computes the next level from src according to the strategy in result.
*/
static inline void compute_strategy_level(vset_t strategy_level, const int* src, const int player, const recursive_result* strategy) {
// Initialise strategy level to the empty set
vset_clear(strategy_level);
// Find the right strategy level. For each level that contains src, there is either a transition
// to the same level, or (preferrably) to a lower level.
for (int i=0; i < strategy->strategy_boundary_count[player]; i++) {
int begin = (i==0) ? 0 : strategy->strategy_boundaries[player][i-1];
int end = strategy->strategy_boundaries[player][i];
//printf("considering segment %d (begin=%d, end=%d).\n", i, begin, end);
//assert(first <= last);
assert(strategy->strategy_boundaries[player][i]<=strategy->strategy_levels_count[player]);
bool src_found = false;
for (int j = begin; j < end && !src_found; j++) {
if (vset_member(strategy->strategy_levels[player][j], src)) {
if (j==begin) {
vset_union(strategy_level, strategy->strategy_levels[player][j]);
//printf("choosing move from segment %d, moving from level %d to level %d.\n", i, j, j);
} else {
vset_union(strategy_level, strategy->strategy_levels[player][j-1]);
//printf("choosing move from segment %d, moving from level %d to level %d.\n", i, j, j-1);
}
assert(!vset_is_empty(strategy_level));
src_found = true;
}
}
}
// strategy_level now contains any target states that can be reached from src
// in one step and are conform the strategy.
}
/**
* \brief Computes the subset of v that belongs to player <tt>player</tt>.
* \param vars the indices of variables of player <tt>player</tt>.
*/
static inline void
add_variable_subset(vset_t dst, vset_t src, vdom_t domain, int var_index)
{
//Warning(info, "add_variable_subset: var_index=%d", var_index);
int p_len = 1;
int proj[1] = {var_pos}; // position 0 encodes the variable
int match[1] = {var_index}; // the variable
vset_t u = vset_create(domain, -1, NULL);
vset_copy_match_proj(u, src, p_len, proj, variable_projection, match);
if (debug_output_enabled && log_active(infoLong))
{
double e_count;
vset_count(u, NULL, &e_count);
if (e_count > 0) Print(infoLong, "add_variable_subset: %d: %.*g states", var_index, DBL_DIG, e_count);
}
vset_union(dst, u);
vset_destroy(u);
}
int choose_strategy_move(const parity_game* g, const recursive_result* strategy, const int player, const int* src,
int* current_player, bool* strategy_play, bool* result, bool* deadlock, int* dst)
{
int group = -1;
vset_t level = vset_create(g->domain, -1, NULL);
vset_t tmp = vset_create(g->domain, -1, NULL);
vset_t singleton = vset_create(g->domain, -1, NULL);
vset_add(singleton, src);
// Do a random run through the game, conforming to
// the strategy in result.
*current_player = (vset_member(g->v_player[player], src) ? player : 1-player);
Print(hre_debug, "Using strategy of player %d. The position is owned by player %d.", player, *current_player);
if (*current_player==player && vset_member(strategy->win[player], src))
{
//printf("Player %d chooses according to his/her winning strategy.\n", player);
// Choose a transition according to the strategy of player
*strategy_play = true;
vset_t strategy_level = vset_create(g->domain, -1, NULL);
compute_strategy_level(strategy_level, src, player, strategy);
vset_clear(level);
for (int i=0; i < g->num_groups; i++) {
vset_next(tmp, singleton, g->e[i]);
vset_intersect(tmp, strategy_level);
if (!vset_is_empty(tmp))
{
vset_copy(level, tmp);
// Choose a random element:
//printf("Choosing a transition from transition group %d.\n", i);
group = i;
vset_random(level, dst);
break;
}
}
// Check for deadlocks
if (vset_is_empty(level)) {
*deadlock = true;
*result = (*current_player != player);
Print(infoLong, "Deadlock for player %d, player %s has won, result is %s.",
*current_player,
(*current_player==1) ? "0 (even / or)" : "1 (odd / and)",
*result ? "true" : "false");
}
}
else
{
//Print(info, "Not player %d's turn or player %d has no winning strategy. Choosing an arbitrary move for player %d.",
// player, player, *current_player);
// this states belongs to (1-player) or player does not have a winning strategy
*strategy_play = false;
vset_t strategy_level = vset_create(g->domain, -1, NULL);
/*
if (vset_member(result.win[current_player], src))
{
// winning move after all
compute_strategy_level(strategy_level, src, current_player, result);
if (vset_is_empty(strategy_level)) {
Print(info, "Unexpected: src is in win[%d], but strategy_level is empty.", current_player);
} else {
strategy_play = true;
}
}
*/
// choose a random move
vset_clear(level);
for (int i=0; i < g->num_groups; i++) {
vset_next(tmp, singleton, g->e[i]);
if (*strategy_play && !vset_is_empty(tmp)) {
vset_intersect(tmp, strategy_level);
if (!vset_is_empty(tmp))
{
vset_copy(level, tmp);
// Choose a random element:
//printf("Choosing a transition from transition group %d.\n", i);
group = i;
vset_random(level, dst);
break;
}
} else {
vset_union(level, tmp);
}
}
// Check for deadlocks
if (vset_is_empty(level)) {
*deadlock = true;
*result = (*current_player != player);
Print(infoLong, "Deadlock for player %d, player %s has won, result is %s.",
*current_player,
(*current_player==1) ? "0 (even / or)" : "1 (odd / and)",
*result ? "true" : "false");
} else if (!*strategy_play) {
//Print(info, "choose randomly");
vset_random(level, dst);
}
}
return group;
}