dgl.distributed.graph_services.sample_neighbors¶

dgl.distributed.graph_services.
sample_neighbors
(g, nodes, fanout, edge_dir='in', prob=None, replace=False)[source]¶ Sample from the neighbors of the given nodes from a distributed graph.
For each node, a number of inbound (or outbound when
edge_dir == 'out'
) edges will be randomly chosen. The returned graph will contain all the nodes in the original graph, but only the sampled edges.Node/edge features are not preserved. The original IDs of the sampled edges are stored as the dgl.EID feature in the returned graph.
For heterogeneous graphs,
nodes
is a dictionary whose key is node type and the value is typespecific node IDs. Parameters
g (DistGraph) – The distributed graph..
nodes (tensor or dict) – Node IDs to sample neighbors from. If it’s a dict, it should contain only one keyvalue pair to make this API consistent with dgl.sampling.sample_neighbors.
fanout (int) –
The number of edges to be sampled for each node.
If 1 is given, all of the neighbors will be selected.
edge_dir (str, optional) –
Determines whether to sample inbound or outbound edges.
Can take either
in
for inbound edges orout
for outbound edges.prob (str, optional) –
Feature name used as the (unnormalized) probabilities associated with each neighboring edge of a node. The feature must have only one element for each edge.
The features must be nonnegative floats, and the sum of the features of inbound/outbound edges for every node must be positive (though they don’t have to sum up to one). Otherwise, the result will be undefined.
replace (bool, optional) –
If True, sample with replacement.
When sampling with replacement, the sampled subgraph could have parallel edges.
For sampling without replacement, if fanout > the number of neighbors, all the neighbors are sampled. If fanout == 1, all neighbors are collected.
 Returns
A sampled subgraph containing only the sampled neighboring edges. It is on CPU.
 Return type