Impala Documentation

void Impala::Core::Feature::FindSplit	(	int &	dimension,
		double &	value,
		const AnnotatedFeatureTable *	data,
		bool *	filter,
		int	nrClasses,
		int	nrTrials
	)

Find a split by trying random splits and returning the one with the maximum gain.

Actually this function is just 'Optimise' or 'PickBest'. Ideally this would be a function that would taka another function as it's argument (TryRandoSplit). But because of TryRandomSplits three return arguments and C++'s type system this won't work. Boohoo for C++.

Definition at line 131 of file MakeRandomTree.h.

References TryRandomSplit().

Referenced by MakeRandomTree(), and Impala::Core::Feature::TestMakeRandomTree::testFindSplitWithSeed().

00133 {
00134     int bestDim;
00135     double bestVal;
00136     double bestGain;
00137     TryRandomSplit(bestDim, bestVal, bestGain, data, filter, nrClasses);
00138     for(int i=1 ; i<nrTrials ; ++i)
00139     {
00140         int dim;
00141         double val;
00142         double gain;
00143         TryRandomSplit(dim, val, gain, data, filter, nrClasses);
00144         if(gain > bestGain)
00145         {
00146             bestGain = gain;
00147             bestVal = val;
00148             bestDim = dim;
00149         }
00150     }
00151     dimension = bestDim;
00152     value = bestVal;
00153 }

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