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65 lines
2.5 KiB
Python
65 lines
2.5 KiB
Python
# Copyright (c) 2012, James Hensman
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# Licensed under the BSD 3-clause license (see LICENSE.txt)
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import numpy as np
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from ..core.sparse_gp_mpi import SparseGP_MPI
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from .. import likelihoods
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from .. import kern
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from ..inference.latent_function_inference import VarDTC
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from GPy.core.parameterization.variational import NormalPosterior
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class SparseGPRegression(SparseGP_MPI):
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"""
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Gaussian Process model for regression
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This is a thin wrapper around the SparseGP class, with a set of sensible defalts
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:param X: input observations
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:param X_variance: input uncertainties, one per input X
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:param Y: observed values
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:param kernel: a GPy kernel, defaults to rbf+white
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:param Z: inducing inputs (optional, see note)
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:type Z: np.ndarray (num_inducing x input_dim) | None
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:param num_inducing: number of inducing points (ignored if Z is passed, see note)
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:type num_inducing: int
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:rtype: model object
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.. Note:: If no Z array is passed, num_inducing (default 10) points are selected from the data. Other wise num_inducing is ignored
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.. Note:: Multiple independent outputs are allowed using columns of Y
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"""
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def __init__(self, X, Y, kernel=None, Z=None, num_inducing=10, X_variance=None, normalizer=None, mpi_comm=None, name='sparse_gp'):
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num_data, input_dim = X.shape
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# kern defaults to rbf (plus white for stability)
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if kernel is None:
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kernel = kern.RBF(input_dim)# + kern.white(input_dim, variance=1e-3)
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# Z defaults to a subset of the data
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if Z is None:
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i = np.random.permutation(num_data)[:min(num_inducing, num_data)]
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Z = X.view(np.ndarray)[i].copy()
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else:
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assert Z.shape[1] == input_dim
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likelihood = likelihoods.Gaussian()
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if not (X_variance is None):
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X = NormalPosterior(X,X_variance)
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if mpi_comm is not None:
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from ..inference.latent_function_inference.var_dtc_parallel import VarDTC_minibatch
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infr = VarDTC_minibatch(mpi_comm=mpi_comm)
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else:
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infr = VarDTC()
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SparseGP_MPI.__init__(self, X, Y, Z, kernel, likelihood, inference_method=infr, normalizer=normalizer, mpi_comm=mpi_comm, name=name)
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def parameters_changed(self):
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from ..inference.latent_function_inference.var_dtc_parallel import update_gradients_sparsegp,VarDTC_minibatch
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if isinstance(self.inference_method,VarDTC_minibatch):
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update_gradients_sparsegp(self, mpi_comm=self.mpi_comm)
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else:
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super(SparseGPRegression, self).parameters_changed()
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