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tidied the computation of A in sparse_GP

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James Hensman 2013-05-19 19:17:55 +01:00
parent 58b206a245
commit 3f22e61d2d
1 changed files with 12 additions and 29 deletions
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41
GPy/models/sparse_GP.py
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@ -70,39 +70,22 @@ class sparse_GP(GP):
self.Lm = jitchol(self.Kmm)
# The rather complex computations of self.A
if self.likelihood.is_heteroscedastic:
assert self.likelihood.D == 1 # TODO: what if the likelihood is heterscedatic and there are multiple independent outputs?
if self.has_uncertain_inputs:
# psi2_beta_scaled = (self.psi2 * (self.likelihood.precision.flatten().reshape(self.N, 1, 1) / sf2)).sum(0)
psi2_beta_scaled = (self.psi2 * (self.likelihood.precision.flatten().reshape(self.N, 1, 1))).sum(0)
evals, evecs = linalg.eigh(psi2_beta_scaled)
clipped_evals = np.clip(evals, 0., 1e6) # TODO: make clipping configurable
if not np.allclose(evals, clipped_evals):
print "Warning: clipping posterior eigenvalues"
tmp = evecs * np.sqrt(clipped_evals)
tmp, _ = linalg.lapack.flapack.dtrtrs(self.Lm, np.asfortranarray(tmp), lower=1)
self.A = tdot(tmp)
if self.has_uncertain_inputs:
if self.likelihood.is_heteroscedastic:
psi2_beta = (self.psi2 * (self.likelihood.precision.flatten().reshape(self.N, 1, 1))).sum(0)
else:
# tmp = self.psi1 * (np.sqrt(self.likelihood.precision.flatten().reshape(1, self.N)) / sf)
tmp = self.psi1 * (np.sqrt(self.likelihood.precision.flatten().reshape(1, self.N)))
tmp, _ = linalg.lapack.flapack.dtrtrs(self.Lm, np.asfortranarray(tmp), lower=1)
self.A = tdot(tmp)
psi2_beta = self.psi2.sum(0) * self.likelihood.precision
evals, evecs = linalg.eigh(psi2_beta)
clipped_evals = np.clip(evals, 0., 1e6) # TODO: make clipping configurable
tmp = evecs * np.sqrt(clipped_evals)
else:
if self.has_uncertain_inputs:
# psi2_beta_scaled = (self.psi2 * (self.likelihood.precision / sf2)).sum(0)
psi2_beta_scaled = (self.psi2 * (self.likelihood.precision)).sum(0)
evals, evecs = linalg.eigh(psi2_beta_scaled)
clipped_evals = np.clip(evals, 0., 1e15) # TODO: make clipping configurable
if not np.allclose(evals, clipped_evals):
print "Warning: clipping posterior eigenvalues"
tmp = evecs * np.sqrt(clipped_evals)
tmp, _ = linalg.lapack.flapack.dtrtrs(self.Lm, np.asfortranarray(tmp), lower=1)
self.A = tdot(tmp)
if self.likelihood.is_heteroscedastic:
tmp = self.psi1 * (np.sqrt(self.likelihood.precision.flatten().reshape(1, self.N)))
else:
# tmp = self.psi1 * (np.sqrt(self.likelihood.precision) / sf)
tmp = self.psi1 * (np.sqrt(self.likelihood.precision))
tmp, _ = linalg.lapack.flapack.dtrtrs(self.Lm, np.asfortranarray(tmp), lower=1)
self.A = tdot(tmp)
tmp, _ = linalg.lapack.flapack.dtrtrs(self.Lm, np.asfortranarray(tmp), lower=1)
self.A = tdot(tmp)
# factor B
# self.B = np.eye(self.M) / sf2 + self.A