Grayscale Using Fieldler Vector

.py

# %%
import bpy
import networkx as nx  # /path/to/blender's/python -m pip install scipy networkx
obj = bpy.data.objects['Armadillo']
mesh = obj.data
edges = [(e.vertices[0], e.vertices[1]) for e in mesh.edges]
G = nx.Graph(edges)
S = [G.subgraph(c).copy() for c in nx.connected_components(G)]
fiedler_vector = nx.fiedler_vector(S[0])
minV = min(fiedler_vector)
maxV = max(fiedler_vector)
node2fiedler_value = dict(zip(S[0].nodes, fiedler_vector))

name = 'GrayscaleUsingFieldlerVector'
if name not in mesh.vertex_colors:
    mesh.vertex_colors.new(name=name)
vc = mesh.vertex_colors[name].data
for polygon in mesh.polygons:
    for i, v in zip(polygon.loop_indices, polygon.vertices):
        if v in node2fiedler_value:
            ratio = (node2fiedler_value[v]-minV) / (maxV-minV)
            vc[i].color = [ratio, ratio, ratio, 1]
        else:
            vc[i].color = [0, 0, 0, 0]