mosesdecoder/mert/MiraFeatureVector.cpp

#include <cmath>

#include "MiraFeatureVector.h"

using namespace std;

MiraFeatureVector::MiraFeatureVector(const FeatureDataItem& vec)
  : m_dense(vec.dense)
{
  vector<size_t> sparseFeats = vec.sparse.feats();
  bool bFirst = true;
  size_t lastFeat = 0;
  for(size_t i=0;i<sparseFeats.size();i++)
  {
    size_t feat = m_dense.size() + sparseFeats[i];
    m_sparseFeats.push_back(feat);
    m_sparseVals.push_back(vec.sparse.get(sparseFeats[i]));

    // Check ordered property
    if(bFirst) {
      bFirst = false;
    }
    else {
      if(lastFeat>=feat) {
        cerr << "Error: Feature indeces must be strictly ascending coming out of SparseVector" << endl;
        exit(1);
      }
    }
    lastFeat = feat;
  }
}

MiraFeatureVector::MiraFeatureVector(const MiraFeatureVector& other)
  : m_dense(other.m_dense),
    m_sparseFeats(other.m_sparseFeats),
    m_sparseVals(other.m_sparseVals)
{
  if(m_sparseVals.size()!=m_sparseFeats.size()) {
    cerr << "Error: mismatching sparse feat and val sizes" << endl;
    exit(1);
  }
}

MiraFeatureVector::MiraFeatureVector(const vector<ValType>& dense,
                                     const vector<size_t>& sparseFeats,
                                     const vector<ValType>& sparseVals)
  : m_dense(dense),
    m_sparseFeats(sparseFeats),
    m_sparseVals(sparseVals)
{
  if(m_sparseVals.size()!=m_sparseFeats.size()) {
    cerr << "Error: mismatching sparse feat and val sizes" << endl;
    exit(1);
  }
}

ValType MiraFeatureVector::val(size_t index) const {
  if(index < m_dense.size())
    return m_dense[index];
  else
    return m_sparseVals[index];
}

size_t MiraFeatureVector::feat(size_t index) const {
  if(index < m_dense.size())
    return index;
  else
    return m_sparseFeats[index];
}

size_t MiraFeatureVector::size() const {
  return m_dense.size() + m_sparseVals.size();
}

ValType MiraFeatureVector::sqrNorm() const {
  ValType toRet = 0.0;
  for(size_t i=0;i<m_dense.size();i++)
    toRet += m_dense[i]*m_dense[i];
  for(size_t i=0;i<m_sparseVals.size();i++)
    toRet += m_sparseVals[i] * m_sparseVals[i];
  return toRet;
}

MiraFeatureVector operator-(const MiraFeatureVector& a, const MiraFeatureVector& b)
{
  // Dense subtraction
  vector<ValType> dense;
  if(a.m_dense.size()!=b.m_dense.size()) {
    cerr << "Mismatching dense vectors passed to MiraFeatureVector subtraction" << endl;
    exit(1);
  }
  for(size_t i=0;i<a.m_dense.size();i++) {
    dense.push_back(a.m_dense[i] - b.m_dense[i]);
  }

  // Sparse subtraction
  size_t i=0;
  size_t j=0;
  vector<ValType> sparseVals;
  vector<size_t> sparseFeats;
  while(i < a.m_sparseFeats.size() && j < b.m_sparseFeats.size()) {

    if(a.m_sparseFeats[i] < b.m_sparseFeats[j]) {
      sparseFeats.push_back(a.m_sparseFeats[i]);
      sparseVals.push_back(a.m_sparseVals[i]);
      i++;
    }

    else if(b.m_sparseFeats[j] < a.m_sparseFeats[i]) {
      sparseFeats.push_back(b.m_sparseFeats[j]);
      sparseVals.push_back(-b.m_sparseVals[j]);
      j++;
    }

    else {
      ValType newVal  = a.m_sparseVals[i] - b.m_sparseVals[j];
      if(abs(newVal)>1e-6) {
        sparseFeats.push_back(a.m_sparseFeats[i]);
        sparseVals.push_back(newVal);
      }
      i++;
      j++;
    }
  }

  while(i<a.m_sparseFeats.size()) {
    sparseFeats.push_back(a.m_sparseFeats[i]);
    sparseVals.push_back(a.m_sparseVals[i]);
    i++;
  }

  while(j<b.m_sparseFeats.size()) {
    sparseFeats.push_back(b.m_sparseFeats[j]);
    sparseVals.push_back(-b.m_sparseVals[j]);
    j++;
  }

  // Create and return vector
  return MiraFeatureVector(dense,sparseFeats,sparseVals);
}

// --Emacs trickery--
// Local Variables:
// mode:c++
// c-basic-offset:2
// End: