For more complicated scenarios that involve a lot of preprocessing, H2O can be called from R directly. This book will focus more on building models using H2O from R directly. If H2O is set up at a different location instead of localhost, then it can be connected within R by defining the correct ip and port at which the cluster is running:

localH2O = h2o.init(ip = "localhost", port = 54321, nthreads = -1) 

Another critical parameter is the number of threads to be used to build the model; by default, n threads are set to -2, which means that two cores will be used. The value of -1 for n threads will make use of all available cores.