more variational quadtrature code

GPy/likelihoods/bernoulli.py

@@ -113,10 +113,8 @@ class Bernoulli(Likelihood):
         .. Note:
             Each y_i must be in {0, 1}
         """
-        assert np.atleast_1d(inv_link_f).shape == np.atleast_1d(y).shape
         #objective = (inv_link_f**y) * ((1.-inv_link_f)**(1.-y))
-        objective = np.where(y, inv_link_f, 1.-inv_link_f)
-        return np.exp(np.sum(np.log(objective)))
+        return np.where(y, inv_link_f, 1.-inv_link_f)
 
     def logpdf_link(self, inv_link_f, y, Y_metadata=None):
         """
@@ -133,9 +131,7 @@ class Bernoulli(Likelihood):
         :returns: log likelihood evaluated at points inverse link of f.
         :rtype: float
         """
-        assert np.atleast_1d(inv_link_f).shape == np.atleast_1d(y).shape
         #objective = y*np.log(inv_link_f) + (1.-y)*np.log(inv_link_f)
-        state = np.seterr(divide='ignore')
         p = np.where(y==1, inv_link_f, 1.-inv_link_f)
         return np.log(p)
 
@@ -154,13 +150,10 @@ class Bernoulli(Likelihood):
         :returns: gradient of log likelihood evaluated at points inverse link of f.
         :rtype: Nx1 array
         """
-        assert np.atleast_1d(inv_link_f).shape == np.atleast_1d(y).shape
         #grad = (y/inv_link_f) - (1.-y)/(1-inv_link_f)
-        state = np.seterr(divide='ignore')
-        # TODO check y \in {0, 1} or {-1, 1}
-        grad = np.where(y, 1./inv_link_f, -1./(1-inv_link_f))
-        np.seterr(**state)
-        return grad
+        #grad = np.where(y, 1./inv_link_f, -1./(1-inv_link_f))
+        denom = np.where(y, inv_link_f, -(1-inv_link_f))
+        return 1./denom
 
     def d2logpdf_dlink2(self, inv_link_f, y, Y_metadata=None):
         """
@@ -183,13 +176,12 @@ class Bernoulli(Likelihood):
             Will return diagonal of hessian, since every where else it is 0, as the likelihood factorizes over cases
             (the distribution for y_i depends only on inverse link of f_i not on inverse link of f_(j!=i)
         """
-        assert np.atleast_1d(inv_link_f).shape == np.atleast_1d(y).shape
         #d2logpdf_dlink2 = -y/(inv_link_f**2) - (1-y)/((1-inv_link_f)**2)
         state = np.seterr(divide='ignore')
         # TODO check y \in {0, 1} or {-1, 1}
-        d2logpdf_dlink2 = np.where(y, -1./np.square(inv_link_f), -1./np.square(1.-inv_link_f))
-        np.seterr(**state)
-        return d2logpdf_dlink2
+        #d2logpdf_dlink2 = np.where(y, -1./np.square(inv_link_f), -1./np.square(1.-inv_link_f))
+        arg = np.where(y, inv_link_f, 1.-inv_link_f)
+        return -1./np.square(arg)
 
     def d3logpdf_dlink3(self, inv_link_f, y, Y_metadata=None):
         """

GPy/likelihoods/likelihood.py

@@ -146,20 +146,26 @@ class Likelihood(Parameterized):
 
         if gh_points is None:
             gh_x, gh_w = np.polynomial.hermite.hermgauss(20)
+        else:
+            gh_x, gh_w = gh_points
 
         shape = m.shape
         m,v,Y = m.flatten(), v.flatten(), Y.flatten()
 
         #make a grid of points
         X = gh_x[None,:]*np.sqrt(2.*v[:,None]) + m[:,None]
-        logp = self.logpdf(X,Y[:,None])
 
-        p = np.clip(p, 1e-9, 1.-1e-9) # for numerical stability
-        N = stats.norm.pdf(X)
-        F = np.log(p).dot(self.gh_w)
-        NoverP = N/p
-        dF_dm = (NoverP*self.Ysign[:,None]).dot(self.gh_w)
-        dF_dv = -0.5*(NoverP**2 + NoverP*X).dot(self.gh_w)
+        #evaluate the likelhood for the grid. First ax indexes the data (and mu, var) and the second indexes the grid.
+        # broadcast needs to be handled carefully. 
+        logp = self.logpdf(X,Y[:,None])
+        dlogp_dx = self.dlogpdf_df(X, Y[:,None])
+        d2logp_dx2 = self.d2logpdf_df2(X, Y[:,None])
+
+        #average over the gird to get derivatives of the Gaussian's parameters
+        F = np.dot(logp, gh_w)
+        dF_dm = np.dot(dlogp_dx, gh_w)
+        dF_dv = np.dot(d2logp_dx2, gh_w)/2.
+
         return F, dF_dm, dF_dv
 
 

GPy/testing/likelihood_tests.py

@@ -352,7 +352,7 @@ class TestNoiseModels(object):
         print model
         #print model._get_params()
         np.testing.assert_almost_equal(
-                               model.pdf(f.copy(), Y.copy()),
+                model.pdf(f.copy(), Y.copy()).prod(),
                                np.exp(model.logpdf(f.copy(), Y.copy()).sum())
                                )