Source code for graphscope.analytical.app.k_shell

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#
# Copyright 2020 Alibaba Group Holding Limited. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
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from graphscope.framework.app import AppAssets
from graphscope.framework.app import not_compatible_for
from graphscope.framework.app import project_to_simple

__all__ = ["k_shell"]


@project_to_simple
@not_compatible_for("arrow_property", "dynamic_property")
def k_shell(graph, k: int):
    """The k-shell is the subgraph induced by nodes with core number k.
    That is, nodes in the k-core that are not in the (k+1)-core.

    Args:
        graph (:class:`graphscope.Graph`): A simple graph.
        k (int): The order of the k_shell.

    Returns:
        :class:`graphscope.framework.context.VertexDataContextDAGNode`:
            A context with each vertex assigned with a boolean:
                1 if the vertex satisfies k-shell, otherwise 0.
            Evaluated in eager mode.

    Examples:

    .. code:: python

        >>> import graphscope
        >>> from graphscope.dataset import load_p2p_network
        >>> sess = graphscope.session(cluster_type="hosts", mode="eager")
        >>> g = load_p2p_network(sess)
        >>> # project to a simple graph (if needed)
        >>> pg = g.project(vertices={"host": ["id"]}, edges={"connect": ["dist"]})
        >>> c = graphscope.k_shell(pg, k=3)
        >>> sess.close()
    """
    k = int(k)
    return AppAssets(algo="kshell", context="vertex_data")(graph, k)