Greedy Coloring#

We attempt to color a graph using as few colors as possible, where no neighbors of a node can have same color as the node itself.

```import numpy as np
import networkx as nx
import matplotlib.pyplot as plt
import matplotlib.colors as mpl
from matplotlib import animation

G = nx.dodecahedral_graph()

# Apply greedy coloring
graph_coloring = nx.greedy_color(G)
unique_colors = set(graph_coloring.values())

# Assign colors to nodes based on the greedy coloring
graph_color_to_mpl_color = dict(zip(unique_colors, mpl.TABLEAU_COLORS))
node_colors = [graph_color_to_mpl_color[graph_coloring[n]] for n in G.nodes()]

pos = nx.spring_layout(G, seed=14)
nx.draw(
G,
pos,
with_labels=True,
node_size=500,
node_color=node_colors,
edge_color="grey",
font_size=12,
font_color="#333333",
width=2,
)
plt.show()
```

3D graph.#

The same graph plotted in 3D.

```pos = nx.spectral_layout(G, dim=3)
labels = list(G)
nodes = np.array([pos[v] for v in G])
edges = np.array([(pos[u], pos[v]) for u, v in G.edges()])

def init():
ax.clear()
ax.scatter(*nodes.T, alpha=0.9, s=500, color=node_colors)
for vizedge in edges:
ax.plot(*vizedge.T, color="gray")
ax.grid(False)
ax.set_axis_off()
for p in pos:
ax.text(
*pos[p],
labels[p],
size=14,
horizontalalignment="center",
verticalalignment="center",
)

fig = plt.figure(layout="tight")
init()
plt.show()
```

Rotating 3D graph animation.#

Rotation of the 3D graph.

```def _frame_update(index):
ax.view_init(index * 0.2, index * 0.5)

fig = plt.figure(layout="tight")