dgl.DGLHeteroGraph.in_degrees

DGLHeteroGraph.in_degrees(v='__ALL__', etype=None)[source]

Return the in-degree(s) of the given nodes.

It computes the in-degree(s) w.r.t. to the edges of the given edge type.

Parameters
  • v (node IDs) –

    The node IDs. The allowed formats are:

    • int: A single node.

    • Int Tensor: Each element is a node ID. The tensor must have the same device type and ID data type as the graph’s.

    • iterable[int]: Each element is a node ID.

    If not given, return the in-degrees of all the nodes.

  • etype (str or (str, str, str), optional) –

    The type name of the edges. The allowed type name formats are:

    • (str, str, str) for source node type, edge type and destination node type.

    • or one str edge type name if the name can uniquely identify a triplet format in the graph.

    Can be omitted if the graph has only one type of edges.

Returns

The in-degree(s) of the node(s) in a Tensor. The i-th element is the in-degree of the i-th input node. If v is an int, return an int too.

Return type

int or Tensor

Examples

The following example uses PyTorch backend.

>>> import dgl
>>> import torch

Create a homogeneous graph.

>>> g = dgl.graph((torch.tensor([0, 0, 1, 1]), torch.tensor([1, 1, 2, 3])))

Query for all nodes.

>>> g.in_degrees()
tensor([0, 2, 1, 1])

Query for nodes 1 and 2.

>>> g.in_degrees(torch.tensor([1, 2]))
tensor([2, 1])

For a graph of multiple edge types, it is required to specify the edge type in query.

>>> hg = dgl.heterograph({
...     ('user', 'follows', 'user'): (torch.tensor([0, 1]), torch.tensor([1, 2])),
...     ('user', 'plays', 'game'): (torch.tensor([3, 4]), torch.tensor([5, 6]))
... })
>>> hg.in_degrees(torch.tensor([1, 0]), etype='follows')
tensor([1, 0])

See also

out_degrees