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#ifndef SEARCH_VERTEX__
#define SEARCH_VERTEX__
#include "lm/left.hh"
#include "search/types.hh"
#include <boost/unordered_set.hpp>
#include <queue>
#include <vector>
#include <math.h>
#include <stdint.h>
namespace search {
class ContextBase;
struct HypoState {
History history;
lm::ngram::ChartState state;
Score score;
};
class VertexNode {
public:
VertexNode() {}
void InitRoot() { hypos_.clear(); }
/* The steps of building a VertexNode:
* 1. Default construct.
* 2. AppendHypothesis at least once, possibly multiple times.
* 3. FinishAppending with the number of words on left and right guaranteed
* to be common.
* 4. If !Complete(), call BuildExtend to construct the extensions
*/
// Must default construct, call AppendHypothesis 1 or more times then do FinishedAppending.
void AppendHypothesis(const NBestComplete &best) {
assert(hypos_.empty() || !(hypos_.front().state == *best.state));
HypoState hypo;
hypo.history = best.history;
hypo.state = *best.state;
hypo.score = best.score;
hypos_.push_back(hypo);
}
void AppendHypothesis(const HypoState &hypo) {
hypos_.push_back(hypo);
}
// Sort hypotheses for the root.
void FinishRoot();
void FinishedAppending(const unsigned char common_left, const unsigned char common_right);
void BuildExtend();
// Should only happen to a root node when the entire vertex is empty.
bool Empty() const {
return hypos_.empty() && extend_.empty();
}
bool Complete() const {
// HACK: prevent root from being complete. TODO: allow root to be complete.
return hypos_.size() == 1 && extend_.empty();
}
const lm::ngram::ChartState &State() const { return state_; }
bool RightFull() const { return right_full_; }
// Priority relative to other non-terminals. 0 is highest.
unsigned char Niceness() const { return niceness_; }
Score Bound() const {
return bound_;
}
// Will be invalid unless this is a leaf.
History End() const {
assert(hypos_.size() == 1);
return hypos_.front().history;
}
VertexNode &operator[](size_t index) {
assert(!extend_.empty());
return extend_[index];
}
size_t Size() const {
return extend_.size();
}
private:
// Hypotheses to be split.
std::vector<HypoState> hypos_;
std::vector<VertexNode> extend_;
lm::ngram::ChartState state_;
bool right_full_;
unsigned char niceness_;
unsigned char policy_;
Score bound_;
};
class PartialVertex {
public:
PartialVertex() {}
explicit PartialVertex(VertexNode &back) : back_(&back), index_(0) {}
bool Empty() const { return back_->Empty(); }
bool Complete() const { return back_->Complete(); }
const lm::ngram::ChartState &State() const { return back_->State(); }
bool RightFull() const { return back_->RightFull(); }
Score Bound() const { return index_ ? (*back_)[index_].Bound() : back_->Bound(); }
unsigned char Niceness() const { return back_->Niceness(); }
// Split into continuation and alternative, rendering this the continuation.
bool Split(PartialVertex &alternative) {
assert(!Complete());
back_->BuildExtend();
bool ret;
if (index_ + 1 < back_->Size()) {
alternative.index_ = index_ + 1;
alternative.back_ = back_;
ret = true;
} else {
ret = false;
}
back_ = &((*back_)[index_]);
index_ = 0;
return ret;
}
History End() const {
return back_->End();
}
private:
VertexNode *back_;
unsigned int index_;
};
template <class Output> class VertexGenerator;
class Vertex {
public:
Vertex() {}
//PartialVertex RootFirst() const { return PartialVertex(right_); }
PartialVertex RootAlternate() { return PartialVertex(root_); }
//PartialVertex RootLast() const { return PartialVertex(left_); }
bool Empty() const {
return root_.Empty();
}
Score Bound() const {
return root_.Bound();
}
History BestChild() {
// left_ and right_ are not set at the root.
PartialVertex top(RootAlternate());
if (top.Empty()) {
return History();
} else {
PartialVertex continuation;
while (!top.Complete()) {
top.Split(continuation);
}
return top.End();
}
}
private:
template <class Output> friend class VertexGenerator;
template <class Output> friend class RootVertexGenerator;
VertexNode root_;
// These will not be set for the root vertex.
// Branches only on left state.
//VertexNode left_;
// Branches only on right state.
//VertexNode right_;
};
} // namespace search
#endif // SEARCH_VERTEX__
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