easygraph.functions.drawing.positioning module#

easygraph.functions.drawing.positioning.circular_position(G, center=None, scale=1)[source]#

Position nodes on a circle, the dimension is 2.

Parameters:

  • G (easygraph.Graph or easygraph.DiGraph) – A position will be assigned to every node in G

  • center (array-like or None, optional (default : None)) – Coordinate pair around which to center the layout

  • scale (number, optional (default : 1)) – Scale factor for positions

Returns:

pos – A dictionary of positions keyed by node

Return type:

dict

easygraph.functions.drawing.positioning.kamada_kawai_layout(G, dist=None, pos=None, weight='weight', scale=1, center=None, dim=2)[source]#

Position nodes using Kamada-Kawai basic-length cost-function.

Parameters:

  • G (graph or list of nodes) – A position will be assigned to every node in G.

  • dist (dict (default=None)) – A two-level dictionary of optimal distances between nodes, indexed by source and destination node. If None, the distance is computed using shortest_path_length().

  • pos (dict or None optional (default=None)) – Initial positions for nodes as a dictionary with node as keys and values as a coordinate list or tuple. If None, then use circular_layout() for dim >= 2 and a linear layout for dim == 1.

  • weight (string or None optional (default='weight')) – The edge attribute that holds the numerical value used for the edge weight. If None, then all edge weights are 1.

  • scale (number (default: 1)) – Scale factor for positions.

  • center (array-like or None) – Coordinate pair around which to center the layout.

  • dim (int) – Dimension of layout.

Returns:

pos – A dictionary of positions keyed by node

Return type:

dict

Examples

>>> pos = eg.kamada_kawai_layout(G)
easygraph.functions.drawing.positioning.random_position(G, center=None, dim=2, random_seed=None)[source]#

Returns random position for each node in graph G.

Parameters:

  • G (easygraph.Graph or easygraph.DiGraph) –

  • center (array-like or None, optional (default : None)) – Coordinate pair around which to center the layout

  • dim (int, optional (default : 2)) – Dimension of layout

  • random_seed (int or None, optional (default : None)) – Seed for RandomState instance

Returns:

pos – A dictionary of positions keyed by node

Return type:

dict

easygraph.functions.drawing.positioning.rescale_position(pos, scale=1)[source]#

Returns scaled position array to (-scale, scale) in all axes.

Parameters:

  • pos (numpy array) – positions to be scaled. Each row is a position.

  • scale (number, optional (default : 1)) – The size of the resulting extent in all directions.

Returns:

pos – scaled positions. Each row is a position.

Return type:

numpy array

easygraph.functions.drawing.positioning.shell_position(G, nlist=None, scale=1, center=None)[source]#

Position nodes in concentric circles, the dimension is 2.

Parameters:

  • G (easygraph.Graph or easygraph.DiGraph) –

  • nlist (list of lists or None, optional (default : None)) – List of node lists for each shell.

  • scale (number, optional (default : 1)) – Scale factor for positions.

  • center (array-like or None, optional (default : None)) – Coordinate pair around which to center the layout.

Returns:

pos – A dictionary of positions keyed by node

Return type:

dict

Notes

This algorithm currently only works in two dimensions and does not try to minimize edge crossings.