void LogLinearModel::ComputeNegativeFeatureExpectation (LogProbability& _rLogProb,
Features_vec_t& _rvecFeatures,
double _dReward,
double_Vec_t& _rvecExpectedFeatures)
{
size_t iProbs = _rLogProb.Size ();
if (0 == iProbs)
return;
Probability oProb (_rLogProb);
for (size_t i = 0; i < iProbs; ++ i)
{
Features* pFeatures = _rvecFeatures [i];
double dProb = oProb [i] * _dReward;
for (int f = 0; f < pFeatures->Size (); ++ f)
{
size_t iIndex = pFeatures->Index (f);
if (iIndex >= _rvecExpectedFeatures.Size ())
cerr << "[ERROR] out-of-bounds " << iIndex
<< " >= " << _rvecExpectedFeatures.Size ()
<< endl;
_rvecExpectedFeatures [pFeatures->Index (f)] -= dProb * pFeatures->Feature (f);
}
}
}
double LogLinearModel::ComputeLogProb (Features& _rFeatures)
{
double dResult = 0;
for (int i = 0; i < _rFeatures.Size (); ++ i)
{
int iIndex = _rFeatures.Index (i);
if (iIndex >= i_Features)
continue;
dResult += _rFeatures.Feature (i) * vec_Weights [iIndex];
}
return dResult;
}