mosesdecoder/mert/M2.h

#pragma once

#include <cmath>
#include <string>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <iostream>
#include <fstream>
#include <iterator>
#include <algorithm>
#include <limits>
#include <sstream>
#include <boost/algorithm/string.hpp>



namespace MosesTuning
{

namespace M2
{

typedef std::vector<float> Stats;

typedef std::vector<std::string> Sentence;

std::ostream& operator<<(std::ostream& o, Sentence s);

const std::string ToLower(const std::string& str);

struct Annot {
  size_t i;
  size_t j;

  std::string type;
  std::string edit;

  size_t annotator;

  bool operator<(Annot a) const {
    return i < a.i || (i == a.i && j < a.j)
           || (i == a.i && j == a.j && annotator < a.annotator)
           || (i == a.i && j == a.j && annotator == a.annotator && transform(edit) < transform(a.edit));
  }

  bool operator==(Annot a) const {
    return (!(*this < a) && !(a < *this));
  }

  static std::string transform(const std::string& e);

  static bool lowercase;
};

typedef std::set<Annot> Annots;
typedef std::set<size_t> Users;

struct Unit {
  Sentence first;
  Annots second;
  Users third;
};

typedef std::vector<Unit> M2File;

struct Edit {
  Edit(float c = 1.0, size_t ch = 0, size_t unch = 1, std::string e = "")
    : cost(c), changed(ch), unchanged(unch), edit(e) {}

  float cost;
  size_t changed;
  size_t unchanged;
  std::string edit;
};

Edit operator+(Edit& e1, Edit& e2);

struct Vertex {
  Vertex(size_t a = 0, size_t b = 0) : i(a), j(b) {}

  bool operator<(const Vertex &v) const {
    return i < v.i || (i == v.i && j < v.j);
  }

  bool operator==(const Vertex &v) const {
    return i == v.i && j == v.j;
  }

  size_t i;
  size_t j;
};

struct Edge {
  Edge(Vertex vv = Vertex(), Vertex uu = Vertex(), Edit editt = Edit())
    : v(vv), u(uu), edit(editt) {}

  bool operator<(const Edge &e) const {
    return v < e.v || (v == e.v && u < e.u);
  }

  Vertex v;
  Vertex u;
  Edit edit;
};

Edge operator+(Edge e1, Edge e2);

typedef std::vector<size_t> Row;
typedef std::vector<Row> Matrix;

struct Info {
  Info(Vertex vv = Vertex(), Edit editt = Edit())
    : v(vv), edit(editt) {}

  bool operator<(const Info &i) const {
    return v < i.v;
  }

  Vertex v;
  Edit edit;
};

typedef std::set<Info> Track;
typedef std::vector<Track> TrackRow;
typedef std::vector<TrackRow> TrackMatrix;

typedef std::set<Vertex> Vertices;
typedef std::set<Edge> Edges;

class M2
{
private:
  M2File m_m2;

  size_t m_max_unchanged;
  float m_beta;
  bool m_lowercase;
  bool m_verbose;

public:
  M2() : m_max_unchanged(2), m_beta(0.5), m_lowercase(true), m_verbose(false) { }
  M2(size_t max_unchanged, float beta, bool truecase, bool verbose = false)
    : m_max_unchanged(max_unchanged), m_beta(beta), m_lowercase(!truecase), m_verbose(verbose) {
    if(!m_lowercase) {
      Annot::lowercase = false;
    }
  }

  float Beta() {
    return m_beta;
  }

  void ReadM2(const std::string& filename) {
    std::ifstream m2file(filename.c_str());
    std::string line;

    Unit unit;
    bool first = true;

    while(std::getline(m2file, line)) {
      if(line.size() > 2) {
        if(line.substr(0, 2) == "S ") {
          if(!first) {
            if(unit.third.empty())
              unit.third.insert(0);
            m_m2.push_back(unit);
          }
          first = false;

          unit.first = Sentence();
          unit.second = Annots();

          std::string sentenceLine = line.substr(2);
          boost::split(unit.first, sentenceLine, boost::is_any_of(" "), boost::token_compress_on);
        }
        if(line.substr(0, 2) == "A ") {
          std::string annotLine = line.substr(2);

          std::vector<std::string> annot;
          boost::iter_split(annot, annotLine, boost::algorithm::first_finder("|||"));

          if(annot[1] != "noop") {
            Annot a;
            std::stringstream rangeStr(annot[0]);
            rangeStr >> a.i >> a.j;
            a.type = annot[1];
            a.edit = annot[2];

            std::stringstream annotStr(annot[5]);
            annotStr >> a.annotator;

            unit.third.insert(a.annotator);
            unit.second.insert(a);
          } else {
            std::stringstream annotStr(annot[5]);
            size_t annotator;
            annotStr >> annotator;
            unit.third.insert(annotator);
          }
        }
      }
    }
    if(unit.third.empty())
      unit.third.insert(0);
    m_m2.push_back(unit);
  }

  size_t LevenshteinMatrix(const Sentence &s1, const Sentence &s2, Matrix &d, TrackMatrix &bt) {
    size_t n = s1.size();
    size_t m = s2.size();

    if (n == 0)
      return m;
    if (m == 0)
      return n;

    d.resize(n + 1, Row(m + 1, 0));
    bt.resize(n + 1, TrackRow(m + 1));

    for(size_t i = 0; i <= n; ++i) {
      d[i][0] = i;
      if(i > 0)
        bt[i][0].insert(Info(Vertex(i - 1, 0), Edit(1, 1, 0, "")));
    }
    for(size_t j = 0; j <= m; ++j) {
      d[0][j] = j;
      if(j > 0)
        bt[0][j].insert(Info(Vertex(0, j - 1), Edit(1, 1, 0, s2[j - 1])));
    }

    int cost;
    for(size_t i = 1; i <= n; ++i) {
      for(size_t j = 1; j <= m; ++j) {
        if(Annot::transform(s1[i-1]) == Annot::transform(s2[j-1]))
          cost = 0;
        else
          cost = 2;

        size_t left = d[i][j - 1] + 1;
        size_t down = d[i - 1][j] + 1;
        size_t diag = d[i - 1][j - 1] + cost;

        d[i][j] = std::min(left, std::min(down, diag));

        if(d[i][j] == left)
          bt[i][j].insert(Info(Vertex(i, j - 1), Edit(1, 1, 0, s2[j - 1])));
        if(d[i][j] == down)
          bt[i][j].insert(Info(Vertex(i - 1, j), Edit(1, 1, 0, "")));
        if(d[i][j] == diag)
          bt[i][j].insert(Info(Vertex(i - 1, j - 1), cost ? Edit(1, 1, 0, s2[j - 1]) : Edit(1, 0, 1, s2[j - 1]) ));
      }
    }
    return d[n][m];
  }


  void BuildGraph(const TrackMatrix &bt, Vertices &V, Edges &E) {
    Vertex start(bt.size() - 1, bt[0].size() - 1);

    std::queue<Vertex> Q;
    Q.push(start);
    while(!Q.empty()) {
      Vertex v = Q.front();
      Q.pop();
      if(V.count(v) > 0)
        continue;
      V.insert(v);
      for(Track::iterator it = bt[v.i][v.j].begin();
          it != bt[v.i][v.j].end(); ++it) {
        Edge e(it->v, v, it->edit);
        E.insert(e);
        if(V.count(e.v) == 0)
          Q.push(e.v);
      }
    }

    Edges newE;
    do {
      newE.clear();
      for(Edges::iterator it1 = E.begin(); it1 != E.end(); ++it1) {
        for(Edges::iterator it2 = E.begin(); it2 != E.end(); ++it2) {
          if(it1->u == it2->v) {
            Edge e = *it1 + *it2;
            if(e.edit.changed > 0 &&
                e.edit.unchanged <= m_max_unchanged &&
                E.count(e) == 0)
              newE.insert(e);
          }
        }
      }
      E.insert(newE.begin(), newE.end());
    } while(newE.size() > 0);
  }

  void AddWeights(Edges &E, const Unit &u, size_t aid) {
    for(Edges::iterator it1 = E.begin(); it1 != E.end(); ++it1) {
      if(it1->edit.changed > 0) {
        const_cast<float&>(it1->edit.cost) += 0.001;
        for(Annots::iterator it2 = u.second.begin(); it2 != u.second.end(); ++it2) {
          // if matches an annotator
          if(it1->v.i == it2->i && it1->u.i == it2->j
              && Annot::transform(it1->edit.edit) == Annot::transform(it2->edit)
              && it2->annotator == aid) {
            int newWeight = -(m_max_unchanged + 1) * E.size();
            const_cast<float&>(it1->edit.cost) = newWeight;
          }
        }
      }
    }
  }

  void BellmanFord(Vertices &V, Edges &E) {
    Vertex source(0, 0);
    std::map<Vertex, float> distance;
    std::map<Vertex, Vertex> predecessor;

    for(Vertices::iterator it = V.begin(); it != V.end(); ++it) {
      if(*it == source)
        distance[*it] = 0;
      else {
        distance[*it] = std::numeric_limits<float>::infinity();
      }
    }

    for(size_t i = 1; i < V.size(); ++i) {
      for(Edges::iterator it = E.begin(); it != E.end(); ++it) {
        if(distance[it->v] + it->edit.cost < distance[it->u]) {
          distance[it->u] = distance[it->v] + it->edit.cost;
          predecessor[it->u] = it->v;
        }
      }
    }

    Edges newE;

    Vertex v = *V.rbegin();
    while(true) {
      //std::cout << predecessor[v] << " -> " << v << std::endl;
      Edges::iterator it = E.find(Edge(predecessor[v], v));
      if(it != E.end()) {
        Edge f = *it;
        //std::cout << f << std::endl;
        newE.insert(f);

        v = predecessor[v];
        if(v == source)
          break;
      } else {
        std::cout << "Error" << std::endl;
        break;
      }
    }
    E.clear();
    E.insert(newE.begin(), newE.end());
  }

  void AddStats(const std::vector<Edges> &Es, const Unit &u, Stats &stats, size_t line) {

    std::map<size_t, Stats> statsPerAnnotator;
    for(std::set<size_t>::iterator it = u.third.begin();
        it != u.third.end(); ++it) {
      statsPerAnnotator[*it] = Stats(4, 0);
    }

    for(Annots::iterator it = u.second.begin(); it != u.second.end(); it++)
      statsPerAnnotator[it->annotator][2]++;

    for(std::set<size_t>::iterator ait = u.third.begin();
        ait != u.third.end(); ++ait) {
      for(Edges::iterator eit = Es[*ait].begin(); eit != Es[*ait].end(); ++eit) {
        if(eit->edit.changed > 0) {
          statsPerAnnotator[*ait][1]++;
          Annot f;
          f.i = eit->v.i;
          f.j = eit->u.i;
          f.annotator = *ait;
          f.edit = eit->edit.edit;
          for(Annots::iterator fit = u.second.begin(); fit != u.second.end(); fit++) {
            if(f == *fit)
              statsPerAnnotator[*ait][0]++;
          }
        }
      }
    }
    size_t bestAnnot = 0;
    float  bestF = -1;
    for(std::set<size_t>::iterator it = u.third.begin();
        it != u.third.end(); ++it) {
      Stats localStats = stats;
      localStats[0] += statsPerAnnotator[*it][0];
      localStats[1] += statsPerAnnotator[*it][1];
      localStats[2] += statsPerAnnotator[*it][2];
      if(m_verbose)
        std::cerr << *it << " : " << localStats[0] << " " << localStats[1] << " " << localStats[2] << std::endl;
      float f = FScore(localStats);
      if(m_verbose)
        std::cerr << f << std::endl;
      if(f > bestF) {
        bestF = f;
        bestAnnot = *it;
      }
    }
    if(m_verbose)
      std::cerr << ">> Chosen Annotator for line " << line + 1 << " : " << bestAnnot << std::endl;
    stats[0] += statsPerAnnotator[bestAnnot][0];
    stats[1] += statsPerAnnotator[bestAnnot][1];
    stats[2] += statsPerAnnotator[bestAnnot][2];
  }

  void SufStats(const std::string &sStr, size_t i, Stats &stats) {
    std::string temp = sStr;

    Sentence s;
    boost::split(s, temp, boost::is_any_of(" "), boost::token_compress_on);

    Unit &unit = m_m2[i];

    Matrix d;
    TrackMatrix bt;
    size_t distance = LevenshteinMatrix(unit.first, s, d, bt);

    std::vector<Vertices> Vs(unit.third.size());
    std::vector<Edges> Es(unit.third.size());

    if(distance > unit.first.size()) {
      std::cerr << "Levenshtein distance is greater than source size." << std::endl;
      stats[0] = 0;
      stats[1] = distance;
      stats[2] = 0;
      stats[3] = unit.first.size();
      return;
    } else if(distance > 0) {
      for(size_t j = 0; j < unit.third.size(); j++) {
        BuildGraph(bt, Vs[j], Es[j]);
        AddWeights(Es[j], unit, j);
        BellmanFord(Vs[j], Es[j]);
      }
    }
    AddStats(Es, unit, stats, i);
    stats[3] = unit.first.size();
  }


  float FScore(const Stats& stats) {
    float p = 1.0;
    if(stats[1] != 0)
      p = (float)stats[0] / (float)stats[1];

    float r = 1.0;
    if(stats[2] != 0)
      r = (float)stats[0] / (float)stats[2];

    float denom = (m_beta * m_beta * p + r);
    float f = 0.0;
    if(denom != 0)
      f = ((1 + m_beta * m_beta) * p * r) / denom;
    return f;
  }

  void FScore(const Stats& stats, float &p, float &r, float &f) {
    p = 1.0;
    if(stats[1] != 0)
      p = (float)stats[0] / (float)stats[1];

    r = 1.0;
    if(stats[2] != 0)
      r = (float)stats[0] / (float)stats[2];

    float denom = (m_beta * m_beta * p + r);
    f = 0.0;
    if(denom != 0)
      f = ((1 + m_beta * m_beta) * p * r) / denom;
  }
};

}

}