ue pairs)
   .nBins      - [256] maximum number of quanizaton bins (&lt;=256)
   .maxDepth   - [1] maximum depth of tree
   .minWeight  - [.01] minimum sample weigth to allow split
   .fracFtrs   - [1] fraction of features to sample for each node split
   .nThreads   - [16] max number of computational threads to use

 OUTPUTS
  tree       - learned decision tree model struct w the following fields
   .fids       - [Kx1] feature ids for each node
   .thrs       - [Kx1] threshold corresponding to each fid
   