mosesdecoder/mert/StatisticsBasedScorer.cpp
2012-06-30 20:23:45 +01:00

127 lines
3.9 KiB
C++

//
// StatisticsBasedScorer.cpp
// mert_lib
//
// Created by Hieu Hoang on 23/06/2012.
// Copyright 2012 __MyCompanyName__. All rights reserved.
//
#include <iostream>
#include "StatisticsBasedScorer.h"
using namespace std;
namespace MosesTuning
{
StatisticsBasedScorer::StatisticsBasedScorer(const string& name, const string& config)
: Scorer(name,config) {
//configure regularisation
static string KEY_TYPE = "regtype";
static string KEY_WINDOW = "regwin";
static string KEY_CASE = "case";
static string TYPE_NONE = "none";
static string TYPE_AVERAGE = "average";
static string TYPE_MINIMUM = "min";
static string TRUE = "true";
static string FALSE = "false";
string type = getConfig(KEY_TYPE,TYPE_NONE);
if (type == TYPE_NONE) {
m_regularization_type = NONE;
} else if (type == TYPE_AVERAGE) {
m_regularization_type = AVERAGE;
} else if (type == TYPE_MINIMUM) {
m_regularization_type = MINIMUM;
} else {
throw runtime_error("Unknown scorer regularisation strategy: " + type);
}
// cerr << "Using scorer regularisation strategy: " << type << endl;
const string& window = getConfig(KEY_WINDOW, "0");
m_regularization_window = atoi(window.c_str());
// cerr << "Using scorer regularisation window: " << m_regularization_window << endl;
const string& preserve_case = getConfig(KEY_CASE,TRUE);
if (preserve_case == TRUE) {
m_enable_preserve_case = true;
} else if (preserve_case == FALSE) {
m_enable_preserve_case = false;
}
// cerr << "Using case preservation: " << m_enable_preserve_case << endl;
}
void StatisticsBasedScorer::score(const candidates_t& candidates, const diffs_t& diffs,
statscores_t& scores) const
{
if (!m_score_data) {
throw runtime_error("Score data not loaded");
}
// calculate the score for the candidates
if (m_score_data->size() == 0) {
throw runtime_error("Score data is empty");
}
if (candidates.size() == 0) {
throw runtime_error("No candidates supplied");
}
int numCounts = m_score_data->get(0,candidates[0]).size();
vector<int> totals(numCounts);
for (size_t i = 0; i < candidates.size(); ++i) {
ScoreStats stats = m_score_data->get(i,candidates[i]);
if (stats.size() != totals.size()) {
stringstream msg;
msg << "Statistics for (" << "," << candidates[i] << ") have incorrect "
<< "number of fields. Found: " << stats.size() << " Expected: "
<< totals.size();
throw runtime_error(msg.str());
}
for (size_t k = 0; k < totals.size(); ++k) {
totals[k] += stats.get(k);
}
}
scores.push_back(calculateScore(totals));
candidates_t last_candidates(candidates);
// apply each of the diffs, and get new scores
for (size_t i = 0; i < diffs.size(); ++i) {
for (size_t j = 0; j < diffs[i].size(); ++j) {
size_t sid = diffs[i][j].first;
size_t nid = diffs[i][j].second;
size_t last_nid = last_candidates[sid];
for (size_t k = 0; k < totals.size(); ++k) {
int diff = m_score_data->get(sid,nid).get(k)
- m_score_data->get(sid,last_nid).get(k);
totals[k] += diff;
}
last_candidates[sid] = nid;
}
scores.push_back(calculateScore(totals));
}
// Regularisation. This can either be none, or the min or average as described in
// Cer, Jurafsky and Manning at WMT08.
if (m_regularization_type == NONE || m_regularization_window <= 0) {
// no regularisation
return;
}
// window size specifies the +/- in each direction
statscores_t raw_scores(scores); // copy scores
for (size_t i = 0; i < scores.size(); ++i) {
size_t start = 0;
if (i >= m_regularization_window) {
start = i - m_regularization_window;
}
const size_t end = min(scores.size(), i + m_regularization_window + 1);
if (m_regularization_type == AVERAGE) {
scores[i] = score_average(raw_scores,start,end);
} else {
scores[i] = score_min(raw_scores,start,end);
}
}
}
}