Revision 48270681afc13081094f7f398a1e194c6b07ba9b authored by vdutor on 03 January 2018, 17:44:53 UTC, committed by Mark van der Wilk on 03 January 2018, 17:44:53 UTC
* Outline of new expectations code.

* Quadrature code now uses TensorFlow shape inference.

* General expectations work.

* Expectations RBF kern, not tested

* Add Identity mean function

* General unittests for Expectations

* Add multipledispatch package to travis

* Update tests_expectations

* Expectations of mean functions

* Mean function uncertain conditional

* Uncertain conditional with mean_function. Tested.

* Support for Add and Prod kernels and quadrature fallback decorator

* Refactor expectations unittests

* Psi stats Linear kernel

* Split expectations in different files

* Expectation Linear kernel and Linear mean function

* Remove None's from expectations api

* Removed old ekernels framework

* Add multipledispatch to setup file

* Work on PR feedback, not finished

* Addressed PR feedback

* Support for pairwise xKxz

* Enable expectations unittests

* Renamed `TimeseriesGaussian` to `MarkovGaussian` and added tests.

* Rename some variable, plus note for later test of <x Kxz>_q.

* Update conditionals.py

Add comment

* Change order of inputs to (feat, kern)

* Stef/expectations (#601)

* adding gaussmarkov quad

* don't override the markvogaussian in the quadrature

* can't test

* adding external test

* quadrature code done and works for MarkovGauss

* MarkovGaussian with quad implemented. All tests pass

* Shape comments.

* Removed superfluous autoflow functions for kernel expectations

* Update kernels.py

* Update quadrature.py
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reference.py
import numpy as np

def referenceRbfKernel(X, lengthScale, signalVariance):
    nDataPoints, _ = X.shape
    kernel = np.zeros((nDataPoints, nDataPoints))
    for row_index in range(nDataPoints):
        for column_index in range(nDataPoints):
            vecA = X[row_index,:]
            vecB = X[column_index,:]
            delta = vecA - vecB
            distanceSquared = np.dot(delta.T, delta)
            kernel[row_index, column_index] = signalVariance * np.exp(-0.5 * distanceSquared / lengthScale**2)
    return kernel


def referenceArcCosineKernel( X, order, weightVariances, biasVariance, signalVariance ):
    num_points = X.shape[0]
    kernel = np.empty((num_points, num_points))
    for row in range(num_points):
        for col in range(num_points):
            x = X[row]
            y = X[col]

            numerator = (weightVariances * x).dot(y) + biasVariance

            x_denominator = np.sqrt((weightVariances * x).dot(x) + biasVariance)
            y_denominator = np.sqrt((weightVariances * y).dot(y) + biasVariance)
            denominator = x_denominator * y_denominator

            theta = np.arccos(np.clip(numerator / denominator, -1., 1.))
            if order == 0:
                J = np.pi - theta
            elif order == 1:
                J = np.sin(theta) + (np.pi - theta) * np.cos(theta)
            elif order == 2:
                J = 3. * np.sin(theta) * np.cos(theta)
                J += (np.pi - theta) * (1. + 2. * np.cos(theta) ** 2)

            kernel[row, col] = signalVariance * (1. / np.pi) * J * \
                               x_denominator ** order * \
                               y_denominator ** order
    return kernel


def referencePeriodicKernel( X, lengthScale, signalVariance, period ):
    # Based on the GPy implementation of standard_period kernel
    base = np.pi * (X[:, None, :] - X[None, :, :]) / period
    exp_dist = np.exp( -0.5* np.sum( np.square(  np.sin( base ) / lengthScale ), axis = -1 ) )
    return signalVariance * exp_dist
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