Source code for pgl.nn.pool

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# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
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#     http://www.apache.org/licenses/LICENSE-2.0
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"""This package implements common pooling to help building
graph neural networks.
"""

import numpy as np

import paddle
import paddle.nn as nn
import paddle.nn.functional as F
import pgl
import pgl.math as math

__all__ = ["GraphPool"]


class GraphPool(nn.Layer):
    """Implementation of graph pooling

    This is an implementation of graph pooling

    Args:
        graph: the graph object from (:code:`Graph`)

        feature: A tensor with shape (num_nodes, feature_size).

        pool_type: The type of pooling ("sum", "mean" , "min", "max")

    Return:
        A tensor with shape (num_graph, feature_size)
    """

    def __init__(self):
        super(GraphPool, self).__init__()

    def forward(self, graph, feature, pool_type):
        graph_feat = math.segment_pool(feature, graph.graph_node_id, pool_type)
        return graph_feat