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fallback the implementation of spike and slab prior

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Zhenwen Dai 2015-03-30 21:49:02 +01:00
parent 4f0894b6b7
commit edbb576bfc
4 changed files with 27 additions and 36 deletions
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32
GPy/core/parameterization/variational.py
View file

@ -50,31 +50,29 @@ class SpikeAndSlabPrior(VariationalPrior):
def KL_divergence(self, variational_posterior):
mu = variational_posterior.mean
S = variational_posterior.variance
gamma,gamma1 = variational_posterior.gamma_probabilities()
log_gamma,log_gamma1 = variational_posterior.gamma_log_prob()
gamma = variational_posterior.gamma.values
if len(self.pi.shape)==2:
idx = np.unique(gamma._raveled_index()/gamma.shape[-1])
idx = np.unique(variational_posterior.gamma._raveled_index()/gamma.shape[-1])
pi = self.pi[idx]
else:
pi = self.pi
var_mean = np.square(mu)/self.variance
var_S = (S/self.variance - np.log(S))
var_gamma = (gamma*(log_gamma-np.log(pi))).sum()+(gamma1*(log_gamma1-np.log(1-pi))).sum()
var_gamma = (gamma*np.log(gamma/pi)).sum()+((1-gamma)*np.log((1-gamma)/(1-pi))).sum()
return var_gamma+ (gamma* (np.log(self.variance)-1. +var_mean + var_S)).sum()/2.
def update_gradients_KL(self, variational_posterior):
mu = variational_posterior.mean
S = variational_posterior.variance
gamma,gamma1 = variational_posterior.gamma_probabilities()
log_gamma,log_gamma1 = variational_posterior.gamma_log_prob()
gamma = variational_posterior.gamma.values
if len(self.pi.shape)==2:
idx = np.unique(gamma._raveled_index()/gamma.shape[-1])
idx = np.unique(variational_posterior.gamma._raveled_index()/gamma.shape[-1])
pi = self.pi[idx]
else:
pi = self.pi
variational_posterior.binary_prob.gradient -= (np.log((1-pi)/pi)+log_gamma-log_gamma1+((np.square(mu)+S)/self.variance-np.log(S)+np.log(self.variance)-1.)/2.)*gamma*gamma1
variational_posterior.binary_prob.gradient -= np.log((1-pi)/pi*gamma/(1.-gamma))+((np.square(mu)+S)/self.variance-np.log(S)+np.log(self.variance)-1.)/2.
mu.gradient -= gamma*mu/self.variance
S.gradient -= (1./self.variance - 1./S) * gamma /2.
if self.learnPi:
@ -162,25 +160,9 @@ class SpikeAndSlabPosterior(VariationalPosterior):
binary_prob : the probability of the distribution on the slab part.
"""
super(SpikeAndSlabPosterior, self).__init__(means, variances, name)
self.gamma = Param("binary_prob",binary_prob)
self.gamma = Param("binary_prob",binary_prob,Logistic(0.,1.))
self.link_parameter(self.gamma)
@Cache_this(limit=5)
def gamma_probabilities(self):
prob = np.zeros_like(param_to_array(self.gamma))
prob[self.gamma>-710] = 1./(1.+np.exp(-self.gamma[self.gamma>-710]))
prob1 = -np.zeros_like(param_to_array(self.gamma))
prob1[self.gamma<710] = 1./(1.+np.exp(self.gamma[self.gamma<710]))
return prob, prob1
@Cache_this(limit=5)
def gamma_log_prob(self):
loggamma = param_to_array(self.gamma).copy()
loggamma[loggamma>-40] = -np.log1p(np.exp(-loggamma[loggamma>-40]))
loggamma1 = -param_to_array(self.gamma).copy()
loggamma1[loggamma1>-40] = -np.log1p(np.exp(-loggamma1[loggamma1>-40]))
return loggamma,loggamma1
def set_gradients(self, grad):
self.mean.gradient, self.variance.gradient, self.gamma.gradient = grad

6
GPy/inference/latent_function_inference/var_dtc_parallel.py
View file

@ -169,11 +169,13 @@ class VarDTC_minibatch(LatentFunctionInference):
Kmm = kern.K(Z).copy()
diag.add(Kmm, self.const_jitter)
Lm = jitchol(Kmm, maxtries=100)
if not np.isfinite(Kmm).all():
print Kmm
Lm = jitchol(Kmm)
LmInvPsi2LmInvT = backsub_both_sides(Lm,psi2_full,transpose='right')
Lambda = np.eye(Kmm.shape[0])+LmInvPsi2LmInvT
LL = jitchol(Lambda, maxtries=100)
LL = jitchol(Lambda)
logdet_L = 2.*np.sum(np.log(np.diag(LL)))
b = dtrtrs(LL,dtrtrs(Lm,psi1Y_full.T)[0])[0]
bbt = np.square(b).sum()

20
GPy/kern/_src/psi_comp/ssrbf_psi_comp.py
View file

@ -22,12 +22,14 @@ try:
# _psi1 NxM
mu = variational_posterior.mean
S = variational_posterior.variance
gamma = variational_posterior.binary_prob
N,M,Q = mu.shape[0],Z.shape[0],mu.shape[1]
l2 = np.square(lengthscale)
log_denom1 = np.log(S/l2+1)
log_denom2 = np.log(2*S/l2+1)
log_gamma,log_gamma1 = variational_posterior.gamma_log_prob()
log_gamma = np.log(gamma)
log_gamma1 = np.log(1.-gamma)
variance = float(variance)
psi0 = np.empty(N)
psi0[:] = variance
@ -37,6 +39,7 @@ try:
from ....util.misc import param_to_array
S = param_to_array(S)
mu = param_to_array(mu)
gamma = param_to_array(gamma)
Z = param_to_array(Z)
support_code = """
@ -79,7 +82,7 @@ try:
}
}
"""
weave.inline(code, support_code=support_code, arg_names=['psi1','psi2n','N','M','Q','variance','l2','Z','mu','S','log_denom1','log_denom2','log_gamma','log_gamma1'], type_converters=weave.converters.blitz)
weave.inline(code, support_code=support_code, arg_names=['psi1','psi2n','N','M','Q','variance','l2','Z','mu','S','gamma','log_denom1','log_denom2','log_gamma','log_gamma1'], type_converters=weave.converters.blitz)
psi2 = psi2n.sum(axis=0)
return psi0,psi1,psi2,psi2n
@ -94,12 +97,13 @@ try:
mu = variational_posterior.mean
S = variational_posterior.variance
gamma = variational_posterior.binary_prob
N,M,Q = mu.shape[0],Z.shape[0],mu.shape[1]
l2 = np.square(lengthscale)
log_denom1 = np.log(S/l2+1)
log_denom2 = np.log(2*S/l2+1)
log_gamma,log_gamma1 = variational_posterior.gamma_log_prob()
gamma, gamma1 = variational_posterior.gamma_probabilities()
log_gamma = np.log(gamma)
log_gamma1 = np.log(1.-gamma)
variance = float(variance)
dvar = np.zeros(1)
@ -113,6 +117,7 @@ try:
from ....util.misc import param_to_array
S = param_to_array(S)
mu = param_to_array(mu)
gamma = param_to_array(gamma)
Z = param_to_array(Z)
support_code = """
@ -130,7 +135,6 @@ try:
double Zm1q = Z(m1,q);
double Zm2q = Z(m2,q);
double gnq = gamma(n,q);
double g1nq = gamma1(n,q);
double mu_nq = mu(n,q);
if(m2==0) {
@ -156,7 +160,7 @@ try:
dmu(n,q) += lpsi1*Zmu*d_exp1/(denom*exp_sum);
dS(n,q) += lpsi1*(Zmu2_denom-1.)*d_exp1/(denom*exp_sum)/2.;
dgamma(n,q) += lpsi1*(d_exp1*g1nq-d_exp2*gnq)/exp_sum;
dgamma(n,q) += lpsi1*(d_exp1/gnq-d_exp2/(1.-gnq))/exp_sum;
dl(q) += lpsi1*((Zmu2_denom+Snq/lq)/denom*d_exp1+Zm1q*Zm1q/(lq*lq)*d_exp2)/(2.*exp_sum);
dZ(m1,q) += lpsi1*(-Zmu/denom*d_exp1-Zm1q/lq*d_exp2)/exp_sum;
}
@ -184,7 +188,7 @@ try:
dmu(n,q) += -2.*lpsi2*muZhat/denom*d_exp1/exp_sum;
dS(n,q) += lpsi2*(2.*muZhat2_denom-1.)/denom*d_exp1/exp_sum;
dgamma(n,q) += lpsi2*(d_exp1*g1nq-d_exp2*gnq)/exp_sum;
dgamma(n,q) += lpsi2*(d_exp1/gnq-d_exp2/(1.-gnq))/exp_sum;
dl(q) += lpsi2*(((Snq/lq+muZhat2_denom)/denom+dZm1m2*dZm1m2/(4.*lq*lq))*d_exp1+Z2/(2.*lq*lq)*d_exp2)/exp_sum;
dZ(m1,q) += 2.*lpsi2*((muZhat/denom-dZm1m2/(2*lq))*d_exp1-Zm1q/lq*d_exp2)/exp_sum;
}
@ -192,7 +196,7 @@ try:
}
}
"""
weave.inline(code, support_code=support_code, arg_names=['dL_dpsi1','dL_dpsi2','psi1','psi2n','N','M','Q','variance','l2','Z','mu','S','gamma','gamma1','log_denom1','log_denom2','log_gamma','log_gamma1','dvar','dl','dmu','dS','dgamma','dZ'], type_converters=weave.converters.blitz)
weave.inline(code, support_code=support_code, arg_names=['dL_dpsi1','dL_dpsi2','psi1','psi2n','N','M','Q','variance','l2','Z','mu','S','gamma','log_denom1','log_denom2','log_gamma','log_gamma1','dvar','dl','dmu','dS','dgamma','dZ'], type_converters=weave.converters.blitz)
dl *= 2.*lengthscale
if not ARD:

5
GPy/models/ss_gplvm.py
View file

@ -39,7 +39,10 @@ class SSGPLVM(SparseGP_MPI):
X_variance = np.random.uniform(0,.1,X.shape)
if Gamma is None:
gamma = np.random.randn(X.shape[0], input_dim)
gamma = np.empty_like(X) # The posterior probabilities of the binary variable in the variational approximation
gamma[:] = 0.5 + 0.1 * np.random.randn(X.shape[0], input_dim)
gamma[gamma>1.-1e-9] = 1.-1e-9
gamma[gamma<1e-9] = 1e-9
else:
gamma = Gamma.copy()