Merge branch 'params' of https://github.com/SheffieldML/GPy into params

This commit is contained in:
Neil Lawrence 2014-03-12 10:32:59 +00:00
commit 86f92869a1
13 changed files with 235 additions and 398 deletions

View file

@ -1,12 +1,9 @@
# Copyright (c) 2012, GPy authors (see AUTHORS.txt).
# Licensed under the BSD 3-clause license (see LICENSE.txt)
import sys
import numpy as np
import itertools
from linear import Linear
from ...core.parameterization import Parameterized
from ...core.parameterization.param import Param
from kern import Kern
class Add(Kern):
@ -42,8 +39,14 @@ class Add(Kern):
else:
return sum([p.K(X[:, i_s], X2[:, i_s]) for p, i_s in zip(self._parameters_, self.input_slices)])
def update_gradients_full(self, dL_dK, X):
[p.update_gradients_full(dL_dK, X[:,i_s]) for p, i_s in zip(self._parameters_, self.input_slices)]
def update_gradients_full(self, dL_dK, X, X2=None):
if X2 is None:
[p.update_gradients_full(dL_dK, X[:,i_s], X2) for p, i_s in zip(self._parameters_, self.input_slices)]
else:
[p.update_gradients_full(dL_dK, X[:,i_s], X2[:, i_s]) for p, i_s in zip(self._parameters_, self.input_slices)]
def update_gradients_diag(self, dL_dKdiag, X):
[p.update_gradients_diag(dL_dKdiag, X[:,i_s]) for p, i_s in zip(self._parameters_, self.input_slices)]
def gradients_X(self, dL_dK, X, X2=None):
"""Compute the gradient of the objective function with respect to X.
@ -68,19 +71,18 @@ class Add(Kern):
def psi0(self, Z, variational_posterior):
return np.sum([p.psi0(Z[:, i_s], mu[:, i_s], S[:, i_s]) for p, i_s in zip(self._parameters_, self.input_slices)],0)
return np.sum([p.psi0(Z[:, i_s], variational_posterior[:, i_s]) for p, i_s in zip(self._parameters_, self.input_slices)],0)
def psi1(self, Z, variational_posterior):
return np.sum([p.psi1(Z[:, i_s], mu[:, i_s], S[:, i_s]) for p, i_s in zip(self._parameters_, self.input_slices)], 0)
return np.sum([p.psi1(Z[:, i_s], variational_posterior[:, i_s]) for p, i_s in zip(self._parameters_, self.input_slices)], 0)
def psi2(self, Z, variational_posterior):
psi2 = np.sum([p.psi2(Z[:, i_s], mu[:, i_s], S[:, i_s]) for p, i_s in zip(self._parameters_, self.input_slices)], 0)
psi2 = np.sum([p.psi2(Z[:, i_s], variational_posterior[:, i_s]) for p, i_s in zip(self._parameters_, self.input_slices)], 0)
# compute the "cross" terms
from white import White
from static import White, Bias
from rbf import RBF
#from rbf_inv import RBFInv
from bias import Bias
from linear import Linear
#ffrom fixed import Fixed
@ -91,24 +93,20 @@ class Add(Kern):
# rbf X bias
#elif isinstance(p1, (Bias, Fixed)) and isinstance(p2, (RBF, RBFInv)):
elif isinstance(p1, Bias) and isinstance(p2, (RBF, Linear)):
tmp = p2.psi1(Z[:,i2], mu[:,i2], S[:,i2])
tmp = p2.psi1(Z[:,i2], variational_posterior[:, i_s])
psi2 += p1.variance * (tmp[:, :, None] + tmp[:, None, :])
#elif isinstance(p2, (Bias, Fixed)) and isinstance(p1, (RBF, RBFInv)):
elif isinstance(p2, Bias) and isinstance(p1, (RBF, Linear)):
tmp = p1.psi1(Z[:,i1], mu[:,i1], S[:,i1])
tmp = p1.psi1(Z[:,i1], variational_posterior[:, i_s])
psi2 += p2.variance * (tmp[:, :, None] + tmp[:, None, :])
else:
raise NotImplementedError, "psi2 cannot be computed for this kernel"
return psi2
def update_gradients_expectations(self, dL_dpsi0, dL_dpsi1, dL_dpsi2, Z, variational_posterior):
from white import White
from rbf import RBF
#from rbf_inv import RBFInv
#from bias import Bias
from linear import Linear
#ffrom fixed import Fixed
from static import White, Bias
mu, S = variational_posterior.mean, variational_posterior.variance
for p1, is1 in zip(self._parameters_, self.input_slices):
#compute the effective dL_dpsi1. Extra terms appear becaue of the cross terms in psi2!
@ -121,20 +119,15 @@ class Add(Kern):
elif isinstance(p2, Bias):
eff_dL_dpsi1 += dL_dpsi2.sum(1) * p2.variance * 2.
else:
eff_dL_dpsi1 += dL_dpsi2.sum(1) * p2.psi1(Z[:,is2], mu[:,is2], S[:,is2]) * 2.
eff_dL_dpsi1 += dL_dpsi2.sum(1) * p2.psi1(Z[:,is2], variational_posterior[:, is1]) * 2.
p1.update_gradients_expectations(dL_dpsi0, eff_dL_dpsi1, dL_dpsi2, mu[:,is1], S[:,is1], Z[:,is1])
p1.update_gradients_expectations(dL_dpsi0, eff_dL_dpsi1, dL_dpsi2, Z[:,is1], variational_posterior[:, is1])
def gradients_Z_expectations(self, dL_dpsi1, dL_dpsi2, Z, variational_posterior):
from white import White
from rbf import RBF
#from rbf_inv import rbfinv
from bias import Bias
from linear import Linear
#ffrom fixed import fixed
from static import White, Bias
target = np.zeros(Z.shape)
for p1, is1 in zip(self._parameters_, self.input_slices):
@ -148,22 +141,17 @@ class Add(Kern):
elif isinstance(p2, Bias):
eff_dL_dpsi1 += dL_dpsi2.sum(1) * p2.variance * 2.
else:
eff_dL_dpsi1 += dL_dpsi2.sum(1) * p2.psi1(Z[:,is2], mu[:,is2], S[:,is2]) * 2.
eff_dL_dpsi1 += dL_dpsi2.sum(1) * p2.psi1(Z[:,is2], variational_posterior[:, is2]) * 2.
target += p1.gradients_z_variational(dL_dpsi0, eff_dL_dpsi1, dL_dpsi2, mu[:,is1], S[:,is1], Z[:,is1])
target += p1.gradients_Z_expectations(eff_dL_dpsi1, dL_dpsi2, Z[:,is1], variational_posterior[:, is1])
return target
def gradients_qX_expectations(self, dL_dpsi0, dL_dpsi1, dL_dpsi2, Z, variational_posterior):
from white import white
from rbf import rbf
#from rbf_inv import rbfinv
#from bias import bias
from linear import linear
#ffrom fixed import fixed
target_mu = np.zeros(mu.shape)
target_S = np.zeros(S.shape)
from static import White, Bias
target_mu = np.zeros(variational_posterior.shape)
target_S = np.zeros(variational_posterior.shape)
for p1, is1 in zip(self._parameters_, self.input_slices):
#compute the effective dL_dpsi1. extra terms appear becaue of the cross terms in psi2!
@ -171,15 +159,15 @@ class Add(Kern):
for p2, is2 in zip(self._parameters_, self.input_slices):
if p2 is p1:
continue
if isinstance(p2, white):
if isinstance(p2, White):
continue
elif isinstance(p2, bias):
elif isinstance(p2, Bias):
eff_dL_dpsi1 += dL_dpsi2.sum(1) * p2.variance * 2.
else:
eff_dL_dpsi1 += dL_dpsi2.sum(1) * p2.psi1(z[:,is2], mu[:,is2], s[:,is2]) * 2.
eff_dL_dpsi1 += dL_dpsi2.sum(1) * p2.psi1(Z[:,is2], variational_posterior[:, is2]) * 2.
a, b = p1.gradients_qX_expectations(dL_dpsi0, eff_dL_dpsi1, dL_dpsi2, mu[:,is1], s[:,is1], z[:,is1])
a, b = p1.gradients_qX_expectations(dL_dpsi0, eff_dL_dpsi1, dL_dpsi2, Z[:,is1], variational_posterior[:, is1])
target_mu += a
target_S += b
return target_mu, target_S

View file

@ -37,6 +37,10 @@ class Kern(Parameterized):
def gradients_X_diag(self, dL_dK, X):
raise NotImplementedError
def update_gradients_diag(self, dL_dKdiag, X):
""" update the gradients of all parameters when using only the diagonal elements of the covariance matrix"""
raise NotImplementedError
def update_gradients_full(self, dL_dK, X, X2):
"""Set the gradients of all parameters when doing full (N) inference."""
raise NotImplementedError
@ -89,7 +93,7 @@ class Kern(Parameterized):
"""
Returns the sensitivity for each dimension of this kernel.
"""
return self.kern.input_sensitivity()
return np.zeros(self.input_dim)
def __add__(self, other):
""" Overloading of the '+' operator. for more control, see self.add """

View file

@ -55,7 +55,7 @@ class White(Static):
def psi2(self, Z, variational_posterior):
return np.zeros((variational_posterior.shape[0], Z.shape[0], Z.shape[0]), dtype=np.float64)
def update_gradients_full(self, dL_dK, X):
def update_gradients_full(self, dL_dK, X, X2=None):
self.variance.gradient = np.trace(dL_dK)
def update_gradients_diag(self, dL_dKdiag, X):
@ -79,10 +79,10 @@ class Bias(Static):
self.variance.gradient = dL_dK.sum()
def update_gradients_diag(self, dL_dKdiag, X):
self.variance.gradient = dL_dK.sum()
self.variance.gradient = dL_dKdiag.sum()
def psi2(self, Z, variational_posterior):
ret = np.empty((mu.shape[0], Z.shape[0], Z.shape[0]), dtype=np.float64)
ret = np.empty((variational_posterior.shape[0], Z.shape[0], Z.shape[0]), dtype=np.float64)
ret[:] = self.variance**2
return ret