Method add_edges

python/dgl/heterograph.py:435–627

r"""Add multiple new edges for the specified edge type The i-th new edge will be from ``u[i]`` to ``v[i]``. Parameters ---------- u : int, tensor, numpy.ndarray, list Source node IDs, ``u[i]`` gives the source node for the i-th new edge. v : int,

(self, u, v, data=None, etype=None)

        self._reset_cached_info()

    def add_edges(self, u, v, data=None, etype=None):
        r"""Add multiple new edges for the specified edge type

        The i-th new edge will be from ``u[i]`` to ``v[i]``.

        Parameters
        ----------
        u : int, tensor, numpy.ndarray, list
            Source node IDs, ``u[i]`` gives the source node for the i-th new edge.
        v : int, tensor, numpy.ndarray, list
            Destination node IDs, ``v[i]`` gives the destination node for the i-th new edge.
        data : dict, optional
            Feature data of the added edges. The i-th row of the feature data
            corresponds to the i-th new edge.
        etype : str or tuple of str, optional
            The type of the new edges. Can be omitted if there is
            only one edge type in the graph.

        Notes
        -----

        * Inplace update is applied to the current graph.
        * If end nodes of adding edges does not exists, add_nodes is invoked
          to add new nodes. The node features of the new nodes will be created
          by initializers defined with :func:`set_n_initializer` (default
          initializer fills zeros). In certain cases, it is recommanded to
          add_nodes first and then add_edges.
        * If the key of ``data`` does not contain some existing feature fields,
          those features for the new edges will be created by initializers
          defined with :func:`set_n_initializer` (default initializer fills zeros).
        * If the key of ``data`` contains new feature fields, those features for
          the old edges will be created by initializers defined with
          :func:`set_n_initializer` (default initializer fills zeros).
        * This function discards the batch information. Please use
          :func:`dgl.DGLGraph.set_batch_num_nodes`
          and :func:`dgl.DGLGraph.set_batch_num_edges` on the transformed graph
          to maintain the information.

        Examples
        --------

        The following example uses PyTorch backend.

        >>> import dgl
        >>> import torch

        **Homogeneous Graphs or Heterogeneous Graphs with A Single Edge Type**

        >>> g = dgl.graph((torch.tensor([0, 1]), torch.tensor([1, 2])))
        >>> g.num_edges()
        2
        >>> g.add_edges(torch.tensor([1, 3]), torch.tensor([0, 1]))
        >>> g.num_edges()
        4

        Since ``u`` or ``v`` contains a non-existing node ID, the nodes are
        added implicitly.
        >>> g.num_nodes()