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Summary:
Introduces a simple
EnsembleMapSaasGPmodel that will replaceget_fitted_map_saas_ensemble(which fits individual non-ensemble models and combines them into a fully Bayesian GP). The model internally is a batchedExactGP, which behaves just like a multi-outputSingleTaskGP. Theposteriormethod is overwritten to produce aMixtureGaussianPosterior, which retains the old behavior of the ensemble model.The benefit of this model class is that it can be fit just like any other GP model, using
ExactMarginalLogLikelihoodandfit_gpytorch_mll. As such, it is fully compatible with Ax's MBM setup (as long asallow_batched_models=False).Differential Revision: D83701925