# Drawing¶

Tools to visualize topologies of D-Wave QPUs and weighted graph problems on them.

Note

Some functionality requires NumPy and/or Matplotlib.

## Chimera Graph Functions¶

Tools to visualize Chimera lattices and weighted graph problems on them.

 `chimera_layout`(G[, scale, center, dim]) Positions the nodes of graph G in a Chimera cross topology. `draw_chimera`(G, **kwargs) Draws graph G in a Chimera cross topology.

## Example¶

This example uses the `chimera_layout()` function to show the positions of nodes of a simple 5-node NetworkX graph in a Chimera lattice. It then uses the `chimera_graph()` and `draw_chimera()` functions to display those positions on a Chimera unit cell.

```>>> import networkx as nx
>>> import dwave_networkx as dnx
>>> import matplotlib.pyplot as plt
>>> H = nx.Graph()
>>> H.add_nodes_from([0, 4, 5, 6, 7])
>>> H.add_edges_from([(0, 4), (0, 5), (0, 6), (0, 7)])
>>> pos=dnx.chimera_layout(H)
>>> pos
{0: array([ 0. , -0.5]),
4: array([ 0.5,  0. ]),
5: array([ 0.5 , -0.25]),
6: array([ 0.5 , -0.75]),
7: array([ 0.5, -1. ])}
>>> # Show graph H on a Chimera unit cell
>>> plt.ion()
>>> G=dnx.chimera_graph(1, 1, 4)  # Draw a Chimera unit cell
>>> dnx.draw_chimera(G)
>>> dnx.draw_chimera(H, node_color='b', node_shape='*', style='dashed', edge_color='b', width=3)
>>> # matplotlib commands to add labels to graphic not shown
``` Graph H (blue) overlaid on a Chimera unit cell (red nodes and black edges).

## Pegasus Graph Functions¶

Tools to visualize Pegasus lattices and weighted graph problems on them.

 `draw_pegasus`(G[, crosses]) Draws graph G in a Pegasus topology. `draw_pegasus_embedding`(G, *args, **kwargs) Draws an embedding onto Pegasus graph G. `pegasus_layout`(G[, scale, center, dim, crosses]) Positions the nodes of graph G in a Pegasus topology. `pegasus_node_placer_2d`(G[, scale, center, ...]) Generates a function to convert Pegasus indices to plottable coordinates.

## Example¶

This example uses the `draw_pegasus()` function to show the positions of nodes of a simple 5-node graph on a small Pegasus lattice.

```>>> import dwave_networkx as dnx
>>> import matplotlib.pyplot as plt
>>> G = dnx.pegasus_graph(2)
>>> H = dnx.pegasus_graph(2, node_list=[4, 40, 41, 42, 43],
edge_list=[(4, 40), (4, 41), (4, 42), (4, 43)])
>>> # Show graph H on a small Pegasus lattice
>>> plt.ion()
>>> # Show graph H on a small Pegasus lattice
>>> plt.ion()
>>> dnx.draw_pegasus(G, with_labels=True, crosses=True, node_color="Yellow")
>>> dnx.draw_pegasus(H, crosses=True, node_color='b', style='dashed',
edge_color='b', width=3)
``` Graph H (blue) overlaid on a small Pegasus lattice(yellow nodes and black edges).