dmlc--dgl
Rhett Ying
82 行
2.7 KiB
ReStructuredText
82 行
2.7 KiB
ReStructuredText
.. _guide-minibatch:
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Chapter 6: Stochastic Training on Large Graphs
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=======================================================
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:ref:`(中文版) <guide_cn-minibatch>`
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If we have a massive graph with, say, millions or even billions of nodes
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or edges, usually full-graph training as described in
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:ref:`guide-training`
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would not work. Consider an :math:`L`-layer graph convolutional network
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with hidden state size :math:`H` running on an :math:`N`-node graph.
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Storing the intermediate hidden states requires :math:`O(NLH)` memory,
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easily exceeding one GPU’s capacity with large :math:`N`.
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This section provides a way to perform stochastic minibatch training,
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where we do not have to fit the feature of all the nodes into GPU.
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Overview of Neighborhood Sampling Approaches
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--------------------------------------------
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Neighborhood sampling methods generally work as the following. For each
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gradient descent step, we select a minibatch of nodes whose final
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representations at the :math:`L`-th layer are to be computed. We then
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take all or some of their neighbors at the :math:`L-1` layer. This
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process continues until we reach the input. This iterative process
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builds the dependency graph starting from the output and working
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backwards to the input, as the figure below shows:
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.. figure:: https://data.dgl.ai/asset/image/guide_6_0_0.png
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:alt: Imgur
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With this, one can save the workload and computation resources for
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training a GNN on a large graph.
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DGL provides a few neighborhood samplers and a pipeline for training a
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GNN with neighborhood sampling, as well as ways to customize your
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sampling strategies.
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Roadmap
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-----------
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The chapter starts with sections for training GNNs stochastically under
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different scenarios.
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* :ref:`guide-minibatch-node-classification-sampler`
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* :ref:`guide-minibatch-edge-classification-sampler`
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* :ref:`guide-minibatch-link-classification-sampler`
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The remaining sections cover more advanced topics, suitable for those who
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wish to develop new sampling algorithms, new GNN modules compatible with
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mini-batch training and understand how evaluation and inference can be
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conducted in mini-batches.
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* :ref:`guide-minibatch-customizing-neighborhood-sampler`
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* :ref:`guide-minibatch-sparse`
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* :ref:`guide-minibatch-custom-gnn-module`
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* :ref:`guide-minibatch-inference`
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The following are performance tips for implementing and using neighborhood
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sampling:
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* :ref:`guide-minibatch-gpu-sampling`
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* :ref:`guide-minibatch-parallelism`
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.. toctree::
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:maxdepth: 1
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:hidden:
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:glob:
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minibatch-node
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minibatch-edge
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minibatch-link
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minibatch-custom-sampler
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minibatch-sparse
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minibatch-nn
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minibatch-inference
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minibatch-gpu-sampling
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minibatch-parallelism
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