FastTreeRegressionTrainer leaves memory allocation happens before actually yes knowing how many leaves are actually yes needed by the model

[superichmann]

my purpose is to allow the model to create as many leaves as it wants. is there a way to achieve that without allocating 8gb of memory for each tree trainer?

var options = new FastTreeRegressionTrainer.Options
{
NumberOfLeaves=int.MaxValue
}

System.OutOfMemoryException: Array dimensions exceeded supported range.
   at Microsoft.ML.Trainers.FastTree.DocumentPartitioning..ctor(Int32 numDocuments, Int32 maxLeaves)
   at Microsoft.ML.Trainers.FastTree.TreeLearner..ctor(Dataset trainData, Int32 numLeaves)
   at Microsoft.ML.Trainers.FastTree.LeastSquaresRegressionTreeLearner..ctor(Dataset trainData, Int32 numLeaves, Int32 minDocsInLeaf, Double entropyCoefficient, Double featureFirstUsePenalty, Double featureReusePenalty, Double softmaxTemperature, Int32 histogramPoolSize, Int32 randomSeed, Double splitFraction, Boolean filterZeros, Boolean allowEmptyTrees, Double gainConfidenceLevel, Int32 maxCategoricalGroupsPerNode, Int32 maxCategoricalSplitPointPerNode, Double bsrMaxTreeOutput, IParallelTraining parallelTraining, Double minDocsPercentageForCategoricalSplit, Bundle bundling, Int32 minDocsForCategoricalSplit, Double bias, IHost host)
   at Microsoft.ML.Trainers.FastTree.BoostingFastTreeTrainerBase`3.ConstructTreeLearner(IChannel ch)
   at Microsoft.ML.Trainers.FastTree.BoostingFastTreeTrainerBase`3.ConstructOptimizationAlgorithm(IChannel ch)
   at Microsoft.ML.Trainers.FastTree.FastTreeRegressionTrainer.ConstructOptimizationAlgorithm(IChannel ch)
   at Microsoft.ML.Trainers.FastTree.FastTreeTrainerBase`3.Initialize(IChannel ch)
   at Microsoft.ML.Trainers.FastTree.FastTreeTrainerBase`3.TrainCore(IChannel ch)
   at Microsoft.ML.Trainers.FastTree.FastTreeRegressionTrainer.TrainModelCore(TrainContext context)
   at Microsoft.ML.Trainers.TrainerEstimatorBase`2.TrainTransformer(IDataView trainSet, IDataView validationSet, IPredictor initPredictor)
   at Microsoft.ML.Trainers.TrainerEstimatorBase`2.Fit(IDataView input)
   at Microsoft.ML.Data.EstimatorChain`1.Fit(IDataView input)
   at Microsoft.ML.Data.EstimatorChain`1.Fit(IDataView input)