void PositionMonteCarloTreeSearch::go(unsigned int depth) {
(void)depth; // depth wird hier nicht benötigt
srand(time(NULL));
MCTSNode *rootNode = new MCTSNode();
int iterations=0;
while(1) {
PositionMonteCarloTreeSearch *rootPos = new PositionMonteCarloTreeSearch(*this);
MCTSNode *selected = rootNode->select(rootPos);
MCTSNode *expanded = selected->expand(rootPos);
double result = expanded->simulate(rootPos);
expanded->update(result);
iterations++;
if (iterations%100==0) {
if (timer.isTimeout() || timer.checkTimeout())
break;
}
delete rootPos;
}
string foundMove=rootNode->getMove();
delete rootNode;
/************************************
* Das Ergebnis der Suche ausgeben. *
************************************/
timer.stopTimer();
double seconds = timer.getStartEndDiffSeconds();
cout << "Move: " << foundMove << endl;
cout << "Time: " << seconds << " seconds" << endl;
cout << "bestmove " << foundMove << endl;
}
void MCTSPolicy::act(double time, const Observation &in, Action *out)
{
// Clear tree at start of episode
if (time == 0.)
{
safe_delete(&root_);
trunk_ = NULL;
}
// Try warm start
if (trunk_ && trunk_->children())
{
double maxdiff = 0;
MCTSNode *selected = trunk_->select(0);
Vector predicted = selected->state();
for (size_t ii=0; ii < in.size(); ++ii)
maxdiff = fmax(maxdiff, fabs(in[ii]-predicted[ii]));
if (maxdiff < 0.05)
{
trunk_ = selected;
selected->orphanize();
CRAWL("Trunk set to selected state " << trunk_->state());
}
else
{
safe_delete(&root_);
trunk_ = NULL;
TRACE("Cannot use warm start: predicted state " << predicted << " differs from actual state " << in);
}
}
// Allocate new tree if warm start was not possible
if (!trunk_)
{
allocate();
root_->init(NULL, 0, in, 0, false);
root_->allocate(discretizer_->size(in));
trunk_ = root_;
}
CRAWL("Trunk set to state " << trunk_->state());
// Search until budget is up
timer t;
size_t searches=0;
while (t.elapsed() < budget_)
{
MCTSNode *node = treePolicy(), *it=node;
size_t depth=0;
while ((it = it->parent()))
depth++;
double reward = 0;
CRAWL("Tree policy selected node with state " << node->state() << " at depth " << depth);
if (!node->terminal() && depth < horizon_)
reward = defaultPolicy(node->state(), horizon_-depth);
CRAWL("Default policy got reward " << reward);
do
{
node->update(reward);
reward = gamma_*reward + node->reward();
} while ((node = node->parent()));
searches++;
}
// Select best action
if (trunk_->children())
{
MCTSNode *node = trunk_->select(0);
*out = discretizer_->at(trunk_->state(), node->action());
out->type = atGreedy;
TRACE("Selected action " << *out << " (Q " << node->q()/node->visits() << ") after " << searches << " searches");
}
else
{
*out = discretizer_->at(in, lrand48()%discretizer_->size(in));
out->type = atExploratory;
TRACE("Selected random action " << *out);
}
}
