Merge of kern/__init__.py.

GPy/core/parameterization/index_operations.py

@@ -184,7 +184,7 @@ class ParameterIndexOperationsView(object):
     def remove(self, prop, indices):
         removed = self._param_index_ops.remove(prop, numpy.array(indices)+self._offset)
         if removed.size > 0:
-            return removed - self._size + 1
+            return removed-self._offset
         return removed
 
 

GPy/core/parameterization/parameter_core.py

@@ -312,7 +312,8 @@ class Indexable(object):
         This does not need to account for shaped parameters, as it
         basically just sums up the parameter sizes which come before param.
         """
-        raise NotImplementedError, "shouldnt happen, offset required from non parameterization object?"
+        return 0
+        #raise NotImplementedError, "shouldnt happen, offset required from non parameterization object?"
 
     def _raveled_index_for(self, param):
         """
@@ -320,7 +321,8 @@ class Indexable(object):
         that is an int array, containing the indexes for the flattened
         param inside this parameterized logic.
         """
-        raise NotImplementedError, "shouldnt happen, raveld index transformation required from non parameterization object?"
+        return param._raveled_index()
+        #raise NotImplementedError, "shouldnt happen, raveld index transformation required from non parameterization object?"
 
 
 class Constrainable(Nameable, Indexable, Observable):
@@ -368,10 +370,10 @@ class Constrainable(Nameable, Indexable, Observable):
         if value is not None:
             self[:] = value
         reconstrained = self.unconstrain()
-        self._add_to_index_operations(self.constraints, reconstrained, __fixed__, warning)
-        rav_i = self._highest_parent_._raveled_index_for(self)
-        self._highest_parent_._set_fixed(rav_i)
+        index = self._add_to_index_operations(self.constraints, reconstrained, __fixed__, warning)
+        self._highest_parent_._set_fixed(self, index)
         self.notify_observers(self, None if trigger_parent else -np.inf)
+        return index
     fix = constrain_fixed
 
     def unconstrain_fixed(self):
@@ -379,7 +381,8 @@ class Constrainable(Nameable, Indexable, Observable):
         This parameter will no longer be fixed.
         """
         unconstrained = self.unconstrain(__fixed__)
-        self._highest_parent_._set_unfixed(unconstrained)
+        self._highest_parent_._set_unfixed(self, unconstrained)
+        return unconstrained
     unfix = unconstrain_fixed
 
     def _ensure_fixes(self):
@@ -388,14 +391,16 @@ class Constrainable(Nameable, Indexable, Observable):
         # Param: ones(self._realsize_
         if not self._has_fixes(): self._fixes_ = np.ones(self.size, dtype=bool)
 
-    def _set_fixed(self, index):
+    def _set_fixed(self, param, index):
         self._ensure_fixes()
-        self._fixes_[index] = FIXED
+        offset = self._offset_for(param)
+        self._fixes_[index+offset] = FIXED
         if np.all(self._fixes_): self._fixes_ = None  # ==UNFIXED
 
-    def _set_unfixed(self, index):
+    def _set_unfixed(self, param, index):
         self._ensure_fixes()
-        self._fixes_[index] = UNFIXED
+        offset = self._offset_for(param)
+        self._fixes_[index+offset] = UNFIXED
         if np.all(self._fixes_): self._fixes_ = None  # ==UNFIXED
 
     def _connect_fixes(self):
@@ -469,8 +474,9 @@ class Constrainable(Nameable, Indexable, Observable):
         """
         self.param_array[...] = transform.initialize(self.param_array)
         reconstrained = self.unconstrain()
-        self._add_to_index_operations(self.constraints, reconstrained, transform, warning)
+        added = self._add_to_index_operations(self.constraints, reconstrained, transform, warning)
         self.notify_observers(self, None if trigger_parent else -np.inf)
+        return added
 
     def unconstrain(self, *transforms):
         """
@@ -549,7 +555,9 @@ class Constrainable(Nameable, Indexable, Observable):
         if warning and reconstrained.size > 0:
             # TODO: figure out which parameters have changed and only print those
             print "WARNING: reconstraining parameters {}".format(self.parameter_names() or self.name)
-        which.add(what, self._raveled_index())
+        index = self._raveled_index()
+        which.add(what, index)
+        return index
 
     def _remove_from_index_operations(self, which, transforms):
         """
@@ -561,9 +569,10 @@ class Constrainable(Nameable, Indexable, Observable):
         removed = np.empty((0,), dtype=int)
         for t in transforms:
             unconstrained = which.remove(t, self._raveled_index())
+            print unconstrained
             removed = np.union1d(removed, unconstrained)
             if t is __fixed__:
-                self._highest_parent_._set_unfixed(unconstrained)
+                self._highest_parent_._set_unfixed(self, unconstrained)
 
         return removed
 

GPy/examples/classification.py

@@ -61,9 +61,9 @@ def toy_linear_1d_classification(seed=default_seed, optimize=True, plot=True):
     if optimize:
         #m.update_likelihood_approximation()
         # Parameters optimization:
-        #m.optimize()
+        m.optimize()
         #m.update_likelihood_approximation()
-        m.pseudo_EM()
+        #m.pseudo_EM()
 
     # Plot
     if plot:

GPy/inference/latent_function_inference/__init__.py

@@ -29,6 +29,7 @@ from exact_gaussian_inference import ExactGaussianInference
 from laplace import Laplace
 from GPy.inference.latent_function_inference.var_dtc import VarDTC
 from expectation_propagation import EP
+from expectation_propagation_dtc import EPDTC
 from dtc import DTC
 from fitc import FITC
 from var_dtc_parallel import VarDTC_minibatch

GPy/inference/latent_function_inference/expectation_propagation.py

@@ -22,7 +22,7 @@ class EP(object):
     def reset(self):
         self.old_mutilde, self.old_vtilde = None, None
 
-    def inference(self, kern, X, likelihood, Y, Y_metadata=None):
+    def inference(self, kern, X, likelihood, Y, Y_metadata=None, Z=None):
         num_data, output_dim = X.shape
         assert output_dim ==1, "ep in 1D only (for now!)"
 

GPy/inference/latent_function_inference/expectation_propagation_dtc.py

@@ -0,0 +1,123 @@
+import numpy as np
+from ...util.linalg import pdinv,jitchol,DSYR,tdot,dtrtrs, dpotrs
+from expectation_propagation import EP
+from posterior import Posterior
+log_2_pi = np.log(2*np.pi)
+
+class EPDTC(EP):
+    #def __init__(self, epsilon=1e-6, eta=1., delta=1.):
+
+    def inference(self, kern, X, Z, likelihood, Y, Y_metadata=None):
+        num_data, output_dim = X.shape
+        assert output_dim ==1, "ep in 1D only (for now!)"
+
+        Kmm = kern.K(Z)
+        Kmn = kern.K(Z,X)
+
+        Lm = jitchol(Kmm)
+        Lmi = dtrtrs(Lm,np.eye(Lm.shape[0]))[0]
+        Kmmi = np.dot(Lmi.T,Lmi)
+        KmmiKmn = np.dot(Kmmi,Kmn)
+        K = np.dot(Kmn.T,KmmiKmn)
+
+
+        mu, Sigma, mu_tilde, tau_tilde, Z_hat = self.expectation_propagation(Kmm, Kmn, Y, likelihood, Y_metadata)
+
+        Wi, LW, LWi, W_logdet = pdinv(K + np.diag(1./tau_tilde))
+
+        alpha, _ = dpotrs(LW, mu_tilde, lower=1)
+
+        log_marginal =  0.5*(-num_data * log_2_pi - W_logdet - np.sum(alpha * mu_tilde)) # TODO: add log Z_hat??
+
+        dL_dK = 0.5 * (tdot(alpha[:,None]) - Wi)
+
+        dL_dthetaL = np.zeros(likelihood.size)#TODO: derivatives of the likelihood parameters
+
+        return Posterior(woodbury_inv=Wi, woodbury_vector=alpha, K=K), log_marginal, {'dL_dK':dL_dK, 'dL_dthetaL':dL_dthetaL}
+
+
+
+    def expectation_propagation(self, Kmm, Kmn, Y, likelihood, Y_metadata):
+
+        num_data, data_dim = Y.shape
+        assert data_dim == 1, "This EP methods only works for 1D outputs"
+
+        KmnKnm = np.dot(Kmn,Kmn.T)
+        Lm = jitchol(Kmm)
+        Lmi = dtrtrs(Lm,np.eye(Lm.shape[0]))[0] #chol_inv(Lm)
+        Kmmi = np.dot(Lmi.T,Lmi)
+        KmmiKmn = np.dot(Kmmi,Kmn)
+        Qnn_diag = np.sum(Kmn*KmmiKmn,-2)
+        LLT0 = Kmm.copy()
+
+        #Initial values - Posterior distribution parameters: q(f|X,Y) = N(f|mu,Sigma)
+        mu = np.zeros(num_data)
+        LLT = Kmm.copy() #Sigma = K.copy()
+        Sigma_diag = Qnn_diag.copy()
+
+        #Initial values - Marginal moments
+        Z_hat = np.empty(num_data,dtype=np.float64)
+        mu_hat = np.empty(num_data,dtype=np.float64)
+        sigma2_hat = np.empty(num_data,dtype=np.float64)
+
+        #initial values - Gaussian factors
+        if self.old_mutilde is None:
+            tau_tilde, mu_tilde, v_tilde = np.zeros((3, num_data))
+        else:
+            assert old_mutilde.size == num_data, "data size mis-match: did you change the data? try resetting!"
+            mu_tilde, v_tilde = self.old_mutilde, self.old_vtilde
+            tau_tilde = v_tilde/mu_tilde
+
+        #Approximation
+        tau_diff = self.epsilon + 1.
+        v_diff = self.epsilon + 1.
+       	iterations = 0
+        while (tau_diff > self.epsilon) or (v_diff > self.epsilon):
+            update_order = np.random.permutation(num_data)
+            for i in update_order:
+                #Cavity distribution parameters
+                tau_cav = 1./Sigma_diag[i] - self.eta*tau_tilde[i]
+                v_cav = mu[i]/Sigma_diag[i] - self.eta*v_tilde[i]
+                #Marginal moments
+                Z_hat[i], mu_hat[i], sigma2_hat[i] = likelihood.moments_match_ep(Y[i], tau_cav, v_cav)#, Y_metadata=None)#=(None if Y_metadata is None else Y_metadata[i]))
+                #Site parameters update
+                delta_tau = self.delta/self.eta*(1./sigma2_hat[i] - 1./Sigma_diag[i])
+                delta_v = self.delta/self.eta*(mu_hat[i]/sigma2_hat[i] - mu[i]/Sigma_diag[i])
+                tau_tilde[i] += delta_tau
+                v_tilde[i] += delta_v
+                #Posterior distribution parameters update
+
+                #DSYR(Sigma, Sigma[:,i].copy(), -delta_tau/(1.+ delta_tau*Sigma[i,i]))
+                DSYR(LLT,Kmn[:,i].copy(),delta_tau)
+                L = jitchol(LLT)
+
+                V,info = dtrtrs(L,Kmn,lower=1)
+                Sigma_diag = np.sum(V*V,-2)
+                si = np.sum(V.T*V[:,i],-1)
+                mu += (delta_v-delta_tau*mu[i])*si
+                #mu = np.dot(Sigma, v_tilde)
+
+            #(re) compute Sigma and mu using full Cholesky decompy
+            LLT = LLT0 + np.dot(Kmn*tau_tilde[None,:],Kmn.T)
+            L = jitchol(LLT)
+            V,info = dtrtrs(L,Kmn,lower=1)
+            V2,info = dtrtrs(L.T,V,lower=0)
+            #Sigma_diag = np.sum(V*V,-2)
+            #Knmv_tilde = np.dot(Kmn,v_tilde)
+            #mu = np.dot(V2.T,Knmv_tilde)
+            Sigma = np.dot(V2.T,V2)
+            mu = np.dot(Sigma,v_tilde)
+
+            #monitor convergence
+            if iterations>0:
+                tau_diff = np.mean(np.square(tau_tilde-tau_tilde_old))
+                v_diff = np.mean(np.square(v_tilde-v_tilde_old))
+            tau_tilde_old = tau_tilde.copy()
+            v_tilde_old = v_tilde.copy()
+
+            tau_diff = 0
+            v_diff = 0
+            iterations += 1
+
+        mu_tilde = v_tilde/tau_tilde
+        return mu, Sigma, mu_tilde, tau_tilde, Z_hat

GPy/models/__init__.py

@@ -16,4 +16,4 @@ from gradient_checker import GradientChecker
 from ss_gplvm import SSGPLVM
 from gp_coregionalized_regression import GPCoregionalizedRegression
 from sparse_gp_coregionalized_regression import SparseGPCoregionalizedRegression
-#.py file not included!!! #from sparse_gp_coregionalized_regression import SparseGPCoregionalizedRegression
+from gp_heteroscedastic_regression import GPHeteroscedasticRegression

GPy/models/gp_classification.py

@@ -21,7 +21,7 @@ class GPClassification(GP):
 
     """
 
-    def __init__(self, X, Y, kernel=None):
+    def __init__(self, X, Y, kernel=None,Y_metadata=None):
         if kernel is None:
             kernel = kern.RBF(X.shape[1])
 

GPy/models/gp_heteroscedastic_regression.py

@@ -0,0 +1,39 @@
+# Copyright (c) 2012 - 2014 the GPy Austhors (see AUTHORS.txt)
+# Licensed under the BSD 3-clause license (see LICENSE.txt)
+
+import numpy as np
+from ..core import GP
+from .. import likelihoods
+from .. import kern
+from .. import util
+
+class GPHeteroscedasticRegression(GP):
+    """
+    Gaussian Process model for heteroscedastic regression
+
+    This is a thin wrapper around the models.GP class, with a set of sensible defaults
+
+    :param X: input observations
+    :param Y: observed values
+    :param kernel: a GPy kernel, defaults to rbf
+    """
+    def __init__(self, X, Y, kernel=None, Y_metadata=None):
+
+        Ny = Y.shape[0]
+
+        if Y_metadata is None:
+            Y_metadata = {'output_index':np.arange(Ny)[:,None]}
+        else:
+            assert Y_metadata['output_index'].shape[0] == Ny
+
+        if kernel is None:
+            kernel = kern.RBF(X.shape[1])
+
+        #Likelihood
+        likelihoods_list = [likelihoods.Gaussian(name="Gaussian_noise_%s" %j) for j in range(Ny)]
+        likelihood = likelihoods.MixedNoise(likelihoods_list=likelihoods_list)
+
+        super(GPHeteroscedasticRegression, self).__init__(X,Y,kernel,likelihood, Y_metadata=Y_metadata)
+
+    def plot(self,*args):
+        return NotImplementedError

GPy/models/sparse_gp_classification.py

@@ -7,6 +7,7 @@ from ..core import SparseGP
 from .. import likelihoods
 from .. import kern
 from ..likelihoods import likelihood
+from ..inference.latent_function_inference import expectation_propagation_dtc
 
 class SparseGPClassification(SparseGP):
     """
@@ -26,16 +27,14 @@ class SparseGPClassification(SparseGP):
 
     """
 
-    def __init__(self, X, Y=None, likelihood=None, kernel=None, normalize_X=False, normalize_Y=False, Z=None, num_inducing=10):
-        if kernel is None:
-            kernel = kern.rbf(X.shape[1])# + kern.white(X.shape[1],1e-3)
+    #def __init__(self, X, Y=None, likelihood=None, kernel=None, normalize_X=False, normalize_Y=False, Z=None, num_inducing=10):
+    def __init__(self, X, Y=None, likelihood=None, kernel=None, Z=None, num_inducing=10, Y_metadata=None):
 
-        if likelihood is None:
-            noise_model = likelihoods.binomial()
-            likelihood = likelihoods.EP(Y, noise_model)
-        elif Y is not None:
-            if not all(Y.flatten() == likelihood.data.flatten()):
-                raise Warning, 'likelihood.data and Y are different.'
+
+        if kernel is None:
+            kernel = kern.RBF(X.shape[1])
+
+        likelihood = likelihoods.Bernoulli()
 
         if Z is None:
             i = np.random.permutation(X.shape[0])[:num_inducing]
@@ -43,6 +42,5 @@ class SparseGPClassification(SparseGP):
         else:
             assert Z.shape[1] == X.shape[1]
 
-        SparseGP.__init__(self, X, likelihood, kernel, Z=Z, normalize_X=normalize_X)
-        self.ensure_default_constraints()
-
+        SparseGP.__init__(self, X, Y, Z, kernel, likelihood, inference_method=expectation_propagation_dtc.EPDTC(), name='SparseGPClassification',Y_metadata=Y_metadata)
+    #def __init__(self, X, Y, Z, kernel, likelihood, inference_method=None, name='sparse gp', Y_metadata=None):

GPy/testing/index_operations_tests.py

@@ -24,12 +24,14 @@ class Test(unittest.TestCase):
         self.assertDictEqual(self.param_index._properties, {})
 
     def test_remove(self):
-        self.param_index.remove(three, np.r_[3:10])
+        removed = self.param_index.remove(three, np.r_[3:10])
+        self.assertListEqual(removed.tolist(), [4, 7])
         self.assertListEqual(self.param_index[three].tolist(), [2])
-        self.param_index.remove(one, [1])
+        removed = self.param_index.remove(one, [1])
+        self.assertListEqual(removed.tolist(), [])
         self.assertListEqual(self.param_index[one].tolist(), [3])
         self.assertListEqual(self.param_index.remove('not in there', []).tolist(), [])
-        self.param_index.remove(one, [9])
+        removed = self.param_index.remove(one, [9])
         self.assertListEqual(self.param_index[one].tolist(), [3])
         self.assertListEqual(self.param_index.remove('not in there', [2,3,4]).tolist(), [])
 
@@ -78,6 +80,13 @@ class Test(unittest.TestCase):
             self.assertEqual(i, i2)
             self.assertTrue(np.all(v == v2))
 
+    def test_indexview_remove(self):
+        removed = self.view.remove(two, [3])
+        self.assertListEqual(removed.tolist(), [3])        
+        removed = self.view.remove(three, np.r_[:5])
+        self.assertListEqual(removed.tolist(), [0, 2])        
+        
+
     def test_misc(self):
         for k,v in self.param_index.copy()._properties.iteritems():
             self.assertListEqual(self.param_index[k].tolist(), v.tolist())

GPy/testing/model_tests.py

@@ -401,6 +401,16 @@ class GradientTests(np.testing.TestCase):
         m.constrain_fixed('.*rbf_var', 1.)
         self.assertTrue(m.checkgrad())
 
+    def test_gp_heteroscedastic_regression(self):
+        num_obs = 25
+        X = np.random.randint(0,140,num_obs)
+        X = X[:,None]
+        Y = 25. + np.sin(X/20.) * 2. + np.random.rand(num_obs)[:,None]
+        kern = GPy.kern.Bias(1) + GPy.kern.RBF(1)
+        m = GPy.models.GPHeteroscedasticRegression(X,Y,kern)
+        self.assertTrue(m.checkgrad())
+
+
 if __name__ == "__main__":
     print "Running unit tests, please be (very) patient..."
     unittest.main()

GPy/testing/parameterized_tests.py

@@ -153,6 +153,18 @@ class ParameterizedTest(unittest.TestCase):
         self.testmodel.randomize()
         np.testing.assert_equal(variances, self.testmodel['.*var'].values())
 
+    def test_fix_unfix(self):
+        fixed = self.testmodel.kern.lengthscale.fix()
+        self.assertListEqual(fixed.tolist(), [0])
+        unfixed = self.testmodel.kern.lengthscale.unfix()
+        self.testmodel.kern.lengthscale.constrain_positive()
+        self.assertListEqual(unfixed.tolist(), [0])
+
+        fixed = self.testmodel.kern.fix()
+        self.assertListEqual(fixed.tolist(), [0,1])
+        unfixed = self.testmodel.kern.unfix()
+        self.assertListEqual(unfixed.tolist(), [0,1])
+
     def test_printing(self):
         print self.test1
         print self.param