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slicing support for kernel input dimension

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This commit is contained in:
Max Zwiessele 2014-03-07 16:59:41 +00:00
parent 5f3524e7da
commit db5fd17609
10 changed files with 178 additions and 65 deletions
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8
GPy/kern/_src/stationary.py
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@ -57,7 +57,7 @@ class Stationary(Kern):
if lengthscale.size != input_dim:
lengthscale = np.ones(input_dim)*lengthscale
else:
lengthscale = np.ones(self.input_dim)
lengthscale = np.ones(self.input_dim)
self.lengthscale = Param('lengthscale', lengthscale, Logexp())
self.variance = Param('variance', variance, Logexp())
assert self.variance.size==1
@ -85,12 +85,14 @@ class Stationary(Kern):
Compute the Euclidean distance between each row of X and X2, or between
each pair of rows of X if X2 is None.
"""
#X, = self._slice_X(X)
if X2 is None:
Xsq = np.sum(np.square(X),1)
r2 = -2.*tdot(X) + (Xsq[:,None] + Xsq[None,:])
util.diag.view(r2)[:,]= 0. # force diagnoal to be zero: sometime numerically a little negative
return np.sqrt(r2)
else:
#X2, = self._slice_X(X2)
X1sq = np.sum(np.square(X),1)
X2sq = np.sum(np.square(X2),1)
return np.sqrt(-2.*np.dot(X, X2.T) + (X1sq[:,None] + X2sq[None,:]))
@ -124,7 +126,6 @@ class Stationary(Kern):
self.lengthscale.gradient = 0.
def update_gradients_full(self, dL_dK, X, X2=None):
self.variance.gradient = np.einsum('ij,ij,i', self.K(X, X2), dL_dK, 1./self.variance)
#now the lengthscale gradient(s)
@ -136,7 +137,7 @@ class Stationary(Kern):
#self.lengthscale.gradient = -((dL_dr*rinv)[:,:,None]*x_xl3).sum(0).sum(0)/self.lengthscale**3
tmp = dL_dr*self._inv_dist(X, X2)
if X2 is None: X2 = X
self.lengthscale.gradient = np.array([np.einsum('ij,ij,...', tmp, np.square(X[:,q:q+1] - X2[:,q:q+1].T), -1./self.lengthscale[q]**3) for q in xrange(self.input_dim)])
self.lengthscale.gradient = np.array([np.einsum('ij,ij,...', tmp, np.square(self._slice_X(X)[:,q:q+1] - self._slice_X(X2)[:,q:q+1].T), -1./self.lengthscale[q]**3) for q in xrange(self.input_dim)])
else:
r = self._scaled_dist(X, X2)
self.lengthscale.gradient = -np.sum(dL_dr*r)/self.lengthscale
@ -176,7 +177,6 @@ class Stationary(Kern):
ret = np.empty(X.shape, dtype=np.float64)
[np.einsum('ij,ij->i', tmp, X[:,q][:,None]-X2[:,q][None,:], out=ret[:,q]) for q in xrange(self.input_dim)]
ret /= self.lengthscale**2
return ret
def gradients_X_diag(self, dL_dKdiag, X):