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171 lines
8 KiB
Python
171 lines
8 KiB
Python
# Copyright (c) 2013, Ricardo Andrade
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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 import GP
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from .. import likelihoods
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from .. import kern
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class GPMultioutputRegression(GP):
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"""
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Multiple output Gaussian process with Gaussian noise
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This is a wrapper around the models.GP class, with a set of sensible defaults
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:param X_list: input observations
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:type X_list: list of numpy arrays (num_data_output_i x input_dim), one array per output
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:param Y_list: observed values
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:type Y_list: list of numpy arrays (num_data_output_i x 1), one array per output
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:param kernel_list: GPy kernels, defaults to rbf
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:type kernel_list: list of GPy kernels
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:param noise_variance_list: noise parameters per output, defaults to 1.0 for every output
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:type noise_variance_list: list of floats
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:param normalize_X: whether to normalize the input data before computing (predictions will be in original scales)
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:type normalize_X: False|True
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:param normalize_Y: whether to normalize the input data before computing (predictions will be in original scales)
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:type normalize_Y: False|True
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:param rank: number tuples of the corregionalization parameters 'coregion_W' (see coregionalize kernel documentation)
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:type rank: integer
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"""
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def __init__(self,X_list,Y_list,kernel_list=None,noise_variance_list=None,normalize_X=False,normalize_Y=False,rank=1):
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self.output_dim = len(Y_list)
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assert len(X_list) == self.output_dim, 'Number of outputs do not match length of inputs list.'
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#Inputs indexing
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i = 0
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index = []
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for x,y in zip(X_list,Y_list):
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assert x.shape[0] == y.shape[0]
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index.append(np.repeat(i,x.size)[:,None])
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i += 1
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index = np.vstack(index)
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X = np.hstack([np.vstack(X_list),index])
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original_dim = X.shape[1] - 1
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#Mixed noise likelihood definition
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likelihood = likelihoods.Gaussian_Mixed_Noise(Y_list,noise_params=noise_variance_list,normalize=normalize_Y)
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#Coregionalization kernel definition
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if kernel_list is None:
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kernel_list = [kern.rbf(original_dim)]
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mkernel = kern.build_lcm(input_dim=original_dim, output_dim=self.output_dim, kernel_list = kernel_list, rank=rank)
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self.multioutput = True
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GP.__init__(self, X, likelihood, mkernel, normalize_X=normalize_X)
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self.ensure_default_constraints()
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def _add_output_index(self,X,output):
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"""
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In a multioutput model, appends an index column to X to specify the output it is related to.
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:param X: Input data
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:type X: np.ndarray, N x self.input_dim
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:param output: output X is related to
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:type output: integer in {0,..., output_dim-1}
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.. Note:: For multiple non-independent outputs models only.
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"""
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assert hasattr(self,'multioutput'), 'This function is for multiple output models only.'
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index = np.ones((X.shape[0],1))*output
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return np.hstack((X,index))
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def plot_single_output(self, X, output):
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"""
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A simple wrapper around self.plot, with appropriate setting of the fixed_inputs argument
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"""
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raise NotImplementedError
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def _raw_predict_single_output(self, _Xnew, output, which_parts='all', full_cov=False,stop=False):
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"""
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For a specific output, calls _raw_predict() at the new point(s) _Xnew.
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This functions calls _add_output_index(), so _Xnew should not have an index column specifying the output.
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---------
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:param Xnew: The points at which to make a prediction
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:type Xnew: np.ndarray, Nnew x self.input_dim
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:param output: output to predict
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:type output: integer in {0,..., output_dim-1}
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:param which_parts: specifies which outputs kernel(s) to use in prediction
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:type which_parts: ('all', list of bools)
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:param full_cov: whether to return the full covariance matrix, or just the diagonal
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.. Note:: For multiple non-independent outputs models only.
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"""
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_Xnew = self._add_output_index(_Xnew, output)
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return self._raw_predict(_Xnew, which_parts=which_parts,full_cov=full_cov, stop=stop)
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def predict_single_output(self, Xnew,output=0, which_parts='all', full_cov=False, likelihood_args=dict()):
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"""
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For a specific output, calls predict() at the new point(s) Xnew.
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This functions calls _add_output_index(), so Xnew should not have an index column specifying the output.
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:param Xnew: The points at which to make a prediction
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:type Xnew: np.ndarray, Nnew x self.input_dim
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:param which_parts: specifies which outputs kernel(s) to use in prediction
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:type which_parts: ('all', list of bools)
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:param full_cov: whether to return the full covariance matrix, or just the diagonal
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:type full_cov: bool
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:returns: mean: posterior mean, a Numpy array, Nnew x self.input_dim
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:returns: var: posterior variance, a Numpy array, Nnew x 1 if full_cov=False, Nnew x Nnew otherwise
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:returns: lower and upper boundaries of the 95% confidence intervals, Numpy arrays, Nnew x self.input_dim
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.. Note:: For multiple non-independent outputs models only.
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"""
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Xnew = self._add_output_index(Xnew, output)
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return self.predict(Xnew, which_parts=which_parts, full_cov=full_cov, likelihood_args=likelihood_args)
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def plot_single_output_f(self, output=None, samples=0, plot_limits=None, which_data='all', which_parts='all', resolution=None, full_cov=False, fignum=None, ax=None):
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"""
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For a specific output, in a multioutput model, this function works just as plot_f on single output models.
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:param output: which output to plot (for multiple output models only)
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:type output: integer (first output is 0)
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:param samples: the number of a posteriori samples to plot
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:param plot_limits: The limits of the plot. If 1D [xmin,xmax], if 2D [[xmin,ymin],[xmax,ymax]]. Defaluts to data limits
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:param which_data: which if the training data to plot (default all)
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:type which_data: 'all' or a slice object to slice self.X, self.Y
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:param which_parts: which of the kernel functions to plot (additively)
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:type which_parts: 'all', or list of bools
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:param resolution: the number of intervals to sample the GP on. Defaults to 200 in 1D and 50 (a 50x50 grid) in 2D
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:type resolution: int
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:param full_cov:
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:type full_cov: bool
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:param fignum: figure to plot on.
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:type fignum: figure number
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:param ax: axes to plot on.
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:type ax: axes handle
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"""
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assert output is not None, "An output must be specified."
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assert len(self.likelihood.noise_model_list) > output, "The model has only %s outputs." %(self.output_dim + 1)
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if which_data == 'all':
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which_data = slice(None)
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if ax is None:
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fig = pb.figure(num=fignum)
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ax = fig.add_subplot(111)
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if self.X.shape[1] == 2:
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Xu = self.X[self.X[:,-1]==output ,0:1]
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Xnew, xmin, xmax = x_frame1D(Xu, plot_limits=plot_limits)
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Xnew_indexed = self._add_output_index(Xnew,output)
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m, v = self._raw_predict(Xnew_indexed, which_parts=which_parts)
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if samples:
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Ysim = self.posterior_samples_f(Xnew_indexed, samples, which_parts=which_parts, full_cov=True)
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for yi in Ysim.T:
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ax.plot(Xnew, yi[:,None], Tango.colorsHex['darkBlue'], linewidth=0.25)
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gpplot(Xnew, m, m - 2 * np.sqrt(v), m + 2 * np.sqrt(v), axes=ax)
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ax.plot(Xu[which_data], self.likelihood.Y[self.likelihood.index==output][:,None], 'kx', mew=1.5)
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ax.set_xlim(xmin, xmax)
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ymin, ymax = min(np.append(self.likelihood.Y, m - 2 * np.sqrt(np.diag(v)[:, None]))), max(np.append(self.likelihood.Y, m + 2 * np.sqrt(np.diag(v)[:, None])))
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ymin, ymax = ymin - 0.1 * (ymax - ymin), ymax + 0.1 * (ymax - ymin)
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ax.set_ylim(ymin, ymax)
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