mosesdecoder/moses/SearchCubePruning.cpp
Ulrich Germann 524109e2ca Reorganisation of options.
The purpose of this effort is to have options local to the individual translation task,
so that they can be changed in the running system in a multi-threaded system.
2015-08-06 21:11:43 +01:00

343 lines
12 KiB
C++

#include "Manager.h"
#include "Util.h"
#include "SearchCubePruning.h"
#include "StaticData.h"
#include "InputType.h"
#include "TranslationOptionCollection.h"
using namespace std;
namespace Moses
{
class BitmapContainerOrderer
{
public:
bool operator()(const BitmapContainer* A, const BitmapContainer* B) const {
if (B->Empty()) {
if (A->Empty()) {
return A < B;
}
return false;
}
if (A->Empty()) {
return true;
}
// Compare the top hypothesis of each bitmap container using the TotalScore, which includes future cost
const float scoreA = A->Top()->GetHypothesis()->GetTotalScore();
const float scoreB = B->Top()->GetHypothesis()->GetTotalScore();
if (scoreA < scoreB) {
return true;
} else if (scoreA > scoreB) {
return false;
} else {
return A < B;
}
}
};
SearchCubePruning::SearchCubePruning(Manager& manager, const InputType &source, const TranslationOptionCollection &transOptColl)
:Search(manager)
,m_source(source)
,m_hypoStackColl(source.GetSize() + 1)
,m_transOptColl(transOptColl)
{
const StaticData &staticData = StaticData::Instance();
std::vector < HypothesisStackCubePruning >::iterator iterStack;
for (size_t ind = 0 ; ind < m_hypoStackColl.size() ; ++ind) {
HypothesisStackCubePruning *sourceHypoColl = new HypothesisStackCubePruning(m_manager);
sourceHypoColl->SetMaxHypoStackSize(m_options.search.stack_size);
sourceHypoColl->SetBeamWidth(m_options.search.beam_width);
m_hypoStackColl[ind] = sourceHypoColl;
}
}
SearchCubePruning::~SearchCubePruning()
{
RemoveAllInColl(m_hypoStackColl);
}
/**
* Main decoder loop that translates a sentence by expanding
* hypotheses stack by stack, until the end of the sentence.
*/
void SearchCubePruning::Decode()
{
const StaticData &SD = StaticData::Instance();
AllOptions const& opts = SD.options();
// initial seed hypothesis: nothing translated, no words produced
Hypothesis *hypo = Hypothesis::Create(m_manager,m_source, m_initialTransOpt);
HypothesisStackCubePruning &firstStack = *static_cast<HypothesisStackCubePruning*>(m_hypoStackColl.front());
firstStack.AddInitial(hypo);
// Call this here because the loop below starts at the second stack.
firstStack.CleanupArcList();
CreateForwardTodos(firstStack);
const size_t PopLimit = StaticData::Instance().options().cube.pop_limit;
VERBOSE(3,"Cube Pruning pop limit is " << PopLimit << std::endl);
const size_t Diversity = StaticData::Instance().options().cube.diversity;
VERBOSE(3,"Cube Pruning diversity is " << Diversity << std::endl)
// go through each stack
size_t stackNo = 1;
int timelimit = m_options.search.timeout;
std::vector < HypothesisStack* >::iterator iterStack;
for (iterStack = m_hypoStackColl.begin() + 1 ; iterStack != m_hypoStackColl.end() ; ++iterStack) {
// check if decoding ran out of time
double _elapsed_time = GetUserTime();
if (timelimit && _elapsed_time > timelimit) {
VERBOSE(1,"Decoding is out of time (" << _elapsed_time << ","
<< timelimit << ")" << std::endl);
return;
}
HypothesisStackCubePruning &sourceHypoColl = *static_cast<HypothesisStackCubePruning*>(*iterStack);
// priority queue which has a single entry for each bitmap container, sorted by score of top hyp
std::priority_queue< BitmapContainer*, std::vector< BitmapContainer* >, BitmapContainerOrderer> BCQueue;
_BMType::const_iterator bmIter;
const _BMType &accessor = sourceHypoColl.GetBitmapAccessor();
for(bmIter = accessor.begin(); bmIter != accessor.end(); ++bmIter) {
// build the first hypotheses
bmIter->second->InitializeEdges();
m_manager.GetSentenceStats().StartTimeManageCubes();
BCQueue.push(bmIter->second);
m_manager.GetSentenceStats().StopTimeManageCubes();
// old algorithm
// bmIter->second->EnsureMinStackHyps(PopLimit);
}
// main search loop, pop k best hyps
for (size_t numpops = 1; numpops <= PopLimit && !BCQueue.empty(); numpops++) {
// get currently best hypothesis in queue
m_manager.GetSentenceStats().StartTimeManageCubes();
BitmapContainer *bc = BCQueue.top();
BCQueue.pop();
m_manager.GetSentenceStats().StopTimeManageCubes();
IFVERBOSE(2) {
m_manager.GetSentenceStats().AddPopped();
}
// push on stack and create successors
bc->ProcessBestHypothesis();
// if there are any hypothesis left in this specific container, add back to queue
m_manager.GetSentenceStats().StartTimeManageCubes();
if (!bc->Empty())
BCQueue.push(bc);
m_manager.GetSentenceStats().StopTimeManageCubes();
}
// ensure diversity, a minimum number of inserted hyps for each bitmap container;
// NOTE: diversity doesn't ensure they aren't pruned at some later point
if (Diversity > 0) {
for(bmIter = accessor.begin(); bmIter != accessor.end(); ++bmIter) {
bmIter->second->EnsureMinStackHyps(Diversity);
}
}
// the stack is pruned before processing (lazy pruning):
VERBOSE(3,"processing hypothesis from next stack");
IFVERBOSE(2) {
m_manager.GetSentenceStats().StartTimeStack();
}
sourceHypoColl.PruneToSize(m_options.search.stack_size);
VERBOSE(3,std::endl);
sourceHypoColl.CleanupArcList();
IFVERBOSE(2) {
m_manager.GetSentenceStats().StopTimeStack();
}
IFVERBOSE(2) {
m_manager.GetSentenceStats().StartTimeSetupCubes();
}
CreateForwardTodos(sourceHypoColl);
IFVERBOSE(2) {
m_manager.GetSentenceStats().StopTimeSetupCubes();
}
stackNo++;
}
}
void SearchCubePruning::CreateForwardTodos(HypothesisStackCubePruning &stack)
{
const _BMType &bitmapAccessor = stack.GetBitmapAccessor();
_BMType::const_iterator iterAccessor;
size_t size = m_source.GetSize();
stack.AddHypothesesToBitmapContainers();
for (iterAccessor = bitmapAccessor.begin() ; iterAccessor != bitmapAccessor.end() ; ++iterAccessor) {
const WordsBitmap &bitmap = iterAccessor->first;
BitmapContainer &bitmapContainer = *iterAccessor->second;
if (bitmapContainer.GetHypothesesSize() == 0) {
// no hypothese to expand. don't bother doing it
continue;
}
// Sort the hypotheses inside the Bitmap Container as they are being used by now.
bitmapContainer.SortHypotheses();
// check bitamp and range doesn't overlap
size_t startPos, endPos;
for (startPos = 0 ; startPos < size ; startPos++) {
if (bitmap.GetValue(startPos))
continue;
// not yet covered
WordsRange applyRange(startPos, startPos);
if (CheckDistortion(bitmap, applyRange)) {
// apply range
CreateForwardTodos(bitmap, applyRange, bitmapContainer);
}
size_t maxSize = size - startPos;
size_t maxSizePhrase = StaticData::Instance().GetMaxPhraseLength();
maxSize = std::min(maxSize, maxSizePhrase);
for (endPos = startPos+1; endPos < startPos + maxSize; endPos++) {
if (bitmap.GetValue(endPos))
break;
WordsRange applyRange(startPos, endPos);
if (CheckDistortion(bitmap, applyRange)) {
// apply range
CreateForwardTodos(bitmap, applyRange, bitmapContainer);
}
}
}
}
}
void
SearchCubePruning::
CreateForwardTodos(WordsBitmap const& bitmap, WordsRange const& range,
BitmapContainer& bitmapContainer)
{
WordsBitmap newBitmap = bitmap;
newBitmap.SetValue(range.GetStartPos(), range.GetEndPos(), true);
size_t numCovered = newBitmap.GetNumWordsCovered();
const TranslationOptionList* transOptList;
transOptList = m_transOptColl.GetTranslationOptionList(range);
const SquareMatrix &futureScore = m_transOptColl.GetFutureScore();
if (transOptList && transOptList->size() > 0) {
HypothesisStackCubePruning& newStack
= *static_cast<HypothesisStackCubePruning*>(m_hypoStackColl[numCovered]);
newStack.SetBitmapAccessor(newBitmap, newStack, range, bitmapContainer,
futureScore, *transOptList);
}
}
bool
SearchCubePruning::
CheckDistortion(const WordsBitmap &hypoBitmap, const WordsRange &range) const
{
// since we check for reordering limits, its good to have that limit handy
int maxDistortion = StaticData::Instance().GetMaxDistortion();
if (maxDistortion < 0) return true;
// if there are reordering limits, make sure it is not violated
// the coverage bitmap is handy here (and the position of the first gap)
size_t const startPos = range.GetStartPos();
size_t const endPos = range.GetEndPos();
// if reordering constraints are used (--monotone-at-punctuation or xml),
// check if passes all
if (!m_source.GetReorderingConstraint().Check(hypoBitmap, startPos, endPos))
return false;
size_t const hypoFirstGapPos = hypoBitmap.GetFirstGapPos();
// any length extension is okay if starting at left-most edge
if (hypoFirstGapPos == startPos) return true;
// starting somewhere other than left-most edge, use caution
// the basic idea is this: we would like to translate a phrase starting
// from a position further right than the left-most open gap. The
// distortion penalty for the following phrase will be computed relative
// to the ending position of the current extension, so we ask now what
// its maximum value will be (which will always be the value of the
// hypothesis starting at the left-most edge). If this vlaue is than
// the distortion limit, we don't allow this extension to be made.
WordsRange bestNextExtension(hypoFirstGapPos, hypoFirstGapPos);
return (m_source.ComputeDistortionDistance(range, bestNextExtension)
<= maxDistortion);
}
/**
* Find best hypothesis on the last stack.
* This is the end point of the best translation, which can be traced back from here
*/
Hypothesis const*
SearchCubePruning::
GetBestHypothesis() const
{
// const HypothesisStackCubePruning &hypoColl = m_hypoStackColl.back();
const HypothesisStack &hypoColl = *m_hypoStackColl.back();
return hypoColl.GetBestHypothesis();
}
/**
* Logging of hypothesis stack sizes
*/
void
SearchCubePruning::
OutputHypoStackSize()
{
std::vector < HypothesisStack* >::const_iterator iterStack = m_hypoStackColl.begin();
TRACE_ERR( "Stack sizes: " << (int)(*iterStack)->size());
for (++iterStack; iterStack != m_hypoStackColl.end() ; ++iterStack) {
TRACE_ERR( ", " << (int)(*iterStack)->size());
}
TRACE_ERR( endl);
}
void SearchCubePruning::PrintBitmapContainerGraph()
{
HypothesisStackCubePruning &lastStack = *static_cast<HypothesisStackCubePruning*>(m_hypoStackColl.back());
const _BMType &bitmapAccessor = lastStack.GetBitmapAccessor();
_BMType::const_iterator iterAccessor;
for (iterAccessor = bitmapAccessor.begin(); iterAccessor != bitmapAccessor.end(); ++iterAccessor) {
cerr << iterAccessor->first << endl;
//BitmapContainer &container = *iterAccessor->second;
}
}
/**
* Logging of hypothesis stack contents
* \param stack number of stack to be reported, report all stacks if 0
*/
void SearchCubePruning::OutputHypoStack(int stack)
{
if (stack >= 0) {
TRACE_ERR( "Stack " << stack << ": " << endl << m_hypoStackColl[stack] << endl);
} else {
// all stacks
int i = 0;
vector < HypothesisStack* >::iterator iterStack;
for (iterStack = m_hypoStackColl.begin() ; iterStack != m_hypoStackColl.end() ; ++iterStack) {
HypothesisStackCubePruning &hypoColl = *static_cast<HypothesisStackCubePruning*>(*iterStack);
TRACE_ERR( "Stack " << i++ << ": " << endl << hypoColl << endl);
}
}
}
const std::vector < HypothesisStack* >& SearchCubePruning::GetHypothesisStacks() const
{
return m_hypoStackColl;
}
}