#!/usr/bin/env python
"""
Weighted Graphs (2)
===================

Alternative visualisation for a weighted graph using edge widths to represent the absolute edge weight,
and colour to represent the sign of the weight.
"""

import numpy as np
import matplotlib.pyplot as plt

from netgraph import Graph

weighted_cube = [
    (0, 1, -0.1),
    (1, 2, -0.2),
    (2, 3, -0.4),
    (3, 2,  0.0),
    (3, 0, -0.2),
    (4, 5,  0.7),
    (5, 6,  0.9),
    (6, 5, -0.2),
    (6, 7,  0.5),
    (7, 4,  0.1),
    (0, 4,  0.5),
    (1, 5, -0.3),
    (5, 1, -0.4),
    (2, 6,  0.8),
    (3, 7,  0.4)
]

edge_width = {(u, v) : 3 * np.abs(w) for (u, v, w) in weighted_cube}
edge_color = {(u, v) : 'blue' if w <=0 else 'red' for (u, v, w) in weighted_cube}
Graph(weighted_cube, edge_width=edge_width, edge_color=edge_color, arrows=True)

plt.show()