public void AdjustTreeOutputs(IChannel ch, RegressionTree tree, DocumentPartitioning partitioning,
ScoreTracker previousScores)
{
_lo.Initialize(tree, partitioning, previousScores);
_hi.Initialize(tree, partitioning, previousScores);
_left.Initialize(tree, partitioning, previousScores);
_right.Initialize(tree, partitioning, previousScores);
_lo.Step = _historicStepSize / _phi;
_left.Step = _historicStepSize;
if (_lo.Loss.CompareTo(_left.Loss) == 1) // backtrack
{
do
{
Rotate(ref _hi, ref _left, ref _lo);
if (_hi.Step <= _minStepSize)
{
goto FINISHED;
}
_lo.Step = _left.Step / _phi;
} while (_lo.Loss.CompareTo(_left.Loss) == 1);
}
else // extend (or stay)
{
_hi.Step = _historicStepSize * _phi;
while (_hi.Loss.CompareTo(_left.Loss) == 1)
{
Rotate(ref _lo, ref _left, ref _hi);
_hi.Step = _left.Step * _phi;
}
}
if (_numPostbracketSteps > 0)
{
_right.Step = _lo.Step + (_hi.Step - _lo.Step) / _phi;
for (int step = 0; step < _numPostbracketSteps; ++step)
{
int cmp = _right.Loss.CompareTo(_left.Loss);
if (cmp == 0)
{
break;
}
if (cmp == 1) // move right
{
Rotate(ref _lo, ref _left, ref _right);
_right.Step = _lo.Step + (_hi.Step - _lo.Step) / _phi;
}
else // move left
{
Rotate(ref _hi, ref _right, ref _left);
if (_hi.Step <= _minStepSize)
{
goto FINISHED;
}
_left.Step = _hi.Step - (_hi.Step - _lo.Step) / _phi;
}
}
// prepare to return _left
if (_right.Loss.CompareTo(_left.Loss) == 1)
{
Swap(ref _left, ref _right);
}
}
FINISHED:
if (_hi.Step < _minStepSize)
{
_left.Step = _minStepSize;
}
else if (_hi.Step == _minStepSize)
{
Swap(ref _hi, ref _left);
}
double bestStep = _left.Step;
ch.Info("multiplier: {0}", bestStep);
_historicStepSize = bestStep;
tree.ScaleOutputsBy(bestStep);
}