bool MCTS::Update(int action, int observation, double reward) {
History.Add(action, observation);
BELIEF_STATE beliefs;
// Find matching vnode from the rest of the tree
QNODE &qnode = Root->Child(action);
VNODE *vnode = qnode.Child(observation);
if( vnode ) {
if( Params.Verbose >= 1 )
cout << "Matched " << vnode->Beliefs().GetNumSamples() << " states" << endl;
beliefs.Copy(vnode->Beliefs(), Simulator);
} else {
if( Params.Verbose >= 1 )
cout << "No matching node found" << endl;
}
// Generate transformed states to avoid particle deprivation
if( Params.UseTransforms )
AddTransforms(Root, beliefs);
// If we still have no particles, fail
if( beliefs.Empty() && (!vnode || vnode->Beliefs().Empty()))
return false;
if( Params.Verbose >= 1 )
Simulator.DisplayBeliefs(beliefs, cout);
// Find a state to initialise prior (only requires fully observed state)
const STATE *state = 0;
if( vnode && !vnode->Beliefs().Empty())
state = vnode->Beliefs().GetSample(0);
else
state = beliefs.GetSample(0);
// Delete old tree and create new root
VNODE::Free(Root, Simulator);
VNODE *newRoot = ExpandNode(state);
newRoot->Beliefs() = beliefs;
Root = newRoot;
return true;
}
bool FlatMCTS::Update(int action, int observation, STATE &state) {
History.Add(action, observation);
if (Simulator.mFullyObservable) { // running an MDP in fact in cases of hplanning
// Delete old tree and create new root
VNODE::Free(Root, Simulator);
Root = ExpandNode(&state, History);
STATE *sample = Simulator.Copy(state);
Root->Beliefs().AddSample(sample);
if (Params.Verbose >= 1) Simulator.DisplayBeliefs(Root->Beliefs(), cout);
return true;
}
else {
BELIEF_STATE beliefs;
// Find matching vnode from the rest of the tree
QNODE &qnode = Root->Child(action);
VNODE *vnode = qnode.Child(observation);
if (vnode) {
if (Params.Verbose >= 1)
cout << "Matched " << vnode->Beliefs().GetNumSamples() << " states"
<< endl;
beliefs.Copy(vnode->Beliefs(), Simulator);
} else {
if (Params.Verbose >= 1) cout << "No matching node found" << endl;
}
if (Params.Verbose >= 1) Simulator.DisplayBeliefs(beliefs, cout);
if (Params.UseParticleFilter) {
ParticleFilter(beliefs);
if (Params.Verbose >= 1) Simulator.DisplayBeliefs(beliefs, cout);
}
// Generate transformed states to avoid particle deprivation
if (Params.UseTransforms) {
AddTransforms(beliefs);
if (Params.Verbose >= 1) Simulator.DisplayBeliefs(beliefs, cout);
}
// If we still have no particles, fail
if (beliefs.Empty() && (!vnode || vnode->Beliefs().Empty()))
return false;
// Find a state to initialise prior (only requires fully observed state)
const STATE *sample = 0;
if (vnode && !vnode->Beliefs().Empty())
sample = vnode->Beliefs().GetSample();
else
sample = beliefs.GetSample();
if (vnode && Params.ReuseTree) {
int size1 = VNODE::GetNumAllocated();
VNODE::Free(Root, Simulator, vnode);
int size2 = VNODE::GetNumAllocated();
assert(size2 < size1);
Root = vnode;
Root->Beliefs().Free(Simulator);
} else { // Delete old tree and create new root
VNODE::Free(Root, Simulator);
Root = ExpandNode(sample, History);
}
Root->Beliefs() = beliefs;
return true;
}
}