void WeakDiscreteTreeLearner::sortIndexesBasedOnDataPositions(indices_t &positions,
const size_t featureIndex) const
{
const FeaturesResponses &featuresResponses = _trainingData->getFeatureResponses();
std::sort(positions.begin(), positions.end(), comparator(featuresResponses, featureIndex));
return;
}
int WeakDiscreteTreeLearner::createNode(
const weights_t &weights,
const indices_t &indices, const size_t start, const size_t end,
TreeNode::shared_ptr &node, double &minError,
const bool isLeft, const int root_node_bottom_height, const int root_node_left_width) const
{
TrainingData::point_t modelWindow = _trainingData->getModelWindow();
const int
shrinking_factor = bootstrapping::integral_channels_computer_t::get_shrinking_factor(),
modelWidth = modelWindow.x() / shrinking_factor ,
modelHeight = modelWindow.y() / shrinking_factor;
//for all features get responses on every image
//find feature with lowest error
const size_t numFeatures = _trainingData->getFeaturesPoolSize();
std::vector<std::pair<double, size_t> >
minErrorsForSearch(numFeatures, std::make_pair(std::numeric_limits<double>::max(), 0));
indices_t indicesCrop;
const int binsize = 1000;
if(start > end)
{
throw std::invalid_argument("WeakDiscreteTreeLearner::createNode received start > end but expected start <= end");
}
indicesCrop.resize(end - start);
std::copy(indices.begin() + start, indices.begin() + end, indicesCrop.begin());
if (indicesCrop.size() == 0)
{
return -1;
}
int return_value = 0;
//find max valid feature index
size_t max_valid_feature_index= 0;
for (size_t featureIndex = numFeatures-1; featureIndex >=0; --featureIndex)
{
if (_trainingData->getFeatureValidity(featureIndex))
{
max_valid_feature_index = featureIndex+1;
break;
}
}
//biasing features not yet supported
double _pushBias = 0;
#pragma omp parallel for reduction(+:return_value) schedule(guided)
for (size_t featureIndex = 0; featureIndex < max_valid_feature_index; ++featureIndex)
{
if (_trainingData->getFeatureValidity(featureIndex)){
const int minv = (*_mins)[featureIndex], maxv = (*_maxs)[featureIndex];
double error = std::numeric_limits<double>::max();
return_value += getErrorEstimate(weights, indicesCrop, featureIndex, binsize, minv, maxv, error);
minErrorsForSearch[featureIndex] = std::make_pair(error, featureIndex);
}
} // end of "for each feature"
//if ( *(std::min_element(minErrorsForSearch.begin(),minErrorsForSearch.end(), sort_pair())) >2)//== mm)
if (return_value < 0)
{
//create dummy node and return;
//node = TreeNode::shared_ptr(new TreeNode(minthr, alphamin, _features[minFeat], minFeat, indicesCrop, splitIndexMin ));
return -1;
}
const int deltaH=0;
//get kth minimal elements
//std::sort(minErrorsForSearch.begin(), minErrorsForSearch.end(), sort_pair());
//thrust::sort(thrust::reinterpret_tag<thrust::omp::tag>(minErrorsForSearch.begin()),
// thrust::reinterpret_tag<thrust::omp::tag>(minErrorsForSearch.end()),
// sort_pair());
std::sort(minErrorsForSearch.begin(),
minErrorsForSearch.end(),
sort_pair());
//search the feature that is highest up in the image
int miny = std::numeric_limits<int>::max();
int minx = std::numeric_limits<int>::max();
int minFeatureIndex = -1;
double errorth;
if (minErrorsForSearch.size() > 0){
errorth= std::min(0.49999999999, minErrorsForSearch[0].first* (1.0+_pushBias));
}
else{
throw std::runtime_error("minErrorsForSearch has size 0: no features in pool?");
}
for (size_t i = 0; i< minErrorsForSearch.size(); ++i){
const int this_feat_idx = minErrorsForSearch[i].second;
double error= minErrorsForSearch[i].first;
if (_pushBias ==0){
minFeatureIndex = this_feat_idx;
break;
}
if (error > errorth)
break;
const Feature this_feat = _trainingData->getFeature(this_feat_idx);
int y = this_feat.y + this_feat.height;
int x = this_feat.x + this_feat.width;
}
if (minFeatureIndex == -1)
{
//create dummy node and return;
//node = TreeNode::shared_ptr(new TreeNode(minthr, alphamin, _features[minFeat], minFeat, indicesCrop, splitIndexMin ));
return -1;
}
sortIndexesBasedOnDataPositions(indicesCrop, minFeatureIndex);
int splitIndexMin = -1;
int minThreshold = -1;
int alphaMin = -1;
if (findThreshold(weights, indicesCrop, minFeatureIndex, minError, minThreshold,
alphaMin, splitIndexMin) == -1)
{
return -1;
}
if(splitIndexMin < 0)
{
throw std::runtime_error("WeakDiscreteTreeLearner::createNode, findThreshold failed to find an adequate split index");
}
// set the shared_ptr to point towards a new node instance
node.reset(new TreeNode(minThreshold, alphaMin,
_trainingData->getFeature(minFeatureIndex),
minFeatureIndex, indicesCrop, splitIndexMin, isLeft));
return 0;
}