Directed Graph

Draw a graph with directed edges using a colormap and different node sizes.

Edges have different colors and alphas (opacity). Drawn using matplotlib.

Out:

/home/runner/work/networkx/networkx/examples/drawing/plot_directed.py:42: MatplotlibDeprecationWarning: Starting from Matplotlib 3.6, colorbar() will steal space from the mappable's axes, rather than from the current axes, to place the colorbar.  To silence this warning, explicitly pass the 'ax' argument to colorbar().
  plt.colorbar(pc)

import matplotlib as mpl
import matplotlib.pyplot as plt
import networkx as nx

seed = 13648  # Seed random number generators for reproducibility
G = nx.random_k_out_graph(10, 3, 0.5, seed=seed)
pos = nx.spring_layout(G, seed=seed)

node_sizes = [3 + 10 * i for i in range(len(G))]
M = G.number_of_edges()
edge_colors = range(2, M + 2)
edge_alphas = [(5 + i) / (M + 4) for i in range(M)]
cmap = plt.cm.plasma

nodes = nx.draw_networkx_nodes(G, pos, node_size=node_sizes, node_color="indigo")
edges = nx.draw_networkx_edges(
    G,
    pos,
    node_size=node_sizes,
    arrowstyle="->",
    arrowsize=10,
    edge_color=edge_colors,
    edge_cmap=cmap,
    width=2,
)
# set alpha value for each edge
for i in range(M):
    edges[i].set_alpha(edge_alphas[i])

pc = mpl.collections.PatchCollection(edges, cmap=cmap)
pc.set_array(edge_colors)
plt.colorbar(pc)

ax = plt.gca()
ax.set_axis_off()
plt.show()