sumops.rst

Sum Operations

LibSPN-Keras offers a convenient way to control the backward pass for sum operations used in the SPNs you build. Internally, LibSPN-Keras defines a couple of sum operations with different backward passes, for gradient as well as EM learning. All of these operations inherit from the SumOpBase class in libspn_keras/sum_ops.py.

NOTE

By default, LibSPN-Keras uses SumOpGradBackprop.

Getting And Setting a Sum Op

These methods allow for setting and getting the current default SumOpBase. By setting a default all sum layers (DenseSum, Conv2DSum, Local2DSum and RootSum) will use that sum op, unless you explicitly provide a SumOpBase instance to any of those classes when initializing them.

.. autofunction:: libspn_keras.config.sum_op.set_default_sum_op

.. autofunction:: libspn_keras.config.sum_op.get_default_sum_op

Sum Operation With Gradients In Backward Pass

.. autoclass:: libspn_keras.sum_ops.SumOpGradBackprop

Sum Operations With EM Signals In Backward Pass

.. autoclass:: libspn_keras.sum_ops.SumOpEMBackprop

.. autoclass:: libspn_keras.sum_ops.SumOpHardEMBackprop

.. autoclass:: libspn_keras.sum_ops.SumOpUnweightedHardEMBackprop