[英]NetworkX: how to create an incidence matrix of a weighted graph?
創建了這樣的網格網絡:
from __future__ import division
import networkx as nx
from pylab import *
import matplotlib.pyplot as plt
%pylab inline
ncols=10
N=10 #Nodes per side
G=nx.grid_2d_graph(N,N)
labels = dict( ((i,j), i + (N-1-j) * N ) for i, j in G.nodes() )
nx.relabel_nodes(G,labels,False)
inds=labels.keys()
vals=labels.values()
inds=[(N-j-1,N-i-1) for i,j in inds]
pos2=dict(zip(vals,inds))
並為每個邊緣分配了與其長度相對應的權重(在這種情況下,所有長度均為1):
#Weights
from math import sqrt
weights = dict()
for source, target in G.edges():
x1, y1 = pos2[source]
x2, y2 = pos2[target]
weights[(source, target)] = round((math.sqrt((x2-x1)**2 + (y2-y1)**2)),3)
for e in G.edges():
G[e[0]][e[1]] = weights[e] #Assigning weights to G.edges()
這就是我的G.edges()
樣子:(起始節點ID,結束節點ID,權重)
[(0, 1, 1.0),
(0, 10, 1.0),
(1, 11, 1.0),
(1, 2, 1.0),... ] #Trivial case: all weights are unitary
如何創建一個考慮了剛剛定義的權重的關聯矩陣? 我想使用nx.incidence_matrix(G, nodelist=None, edgelist=None, oriented=False, weight=None)
,但是在這種情況下weight
的正確值是多少?
文檔說weight
是一個字符串,表示“用於在矩陣中提供每個值的邊緣數據鍵”,但是它的具體含義是什么? 我也沒有找到相關的例子。
有任何想法嗎?
這是一個簡單的示例,顯示了如何正確設置邊緣屬性以及如何生成加權的入射矩陣。
import networkx as nx
from math import sqrt
G = nx.grid_2d_graph(3,3)
for s, t in G.edges():
x1, y1 = s
x2, y2 = t
G[s][t]['weight']=sqrt((x2-x1)**2 + (y2-y1)**2)*42
print(nx.incidence_matrix(G,weight='weight').todense())
輸出值
[[ 42. 42. 42. 0. 0. 0. 0. 0. 0. 0. 0. 0.]
[ 0. 0. 0. 42. 42. 42. 0. 0. 0. 0. 0. 0.]
[ 42. 0. 0. 0. 0. 0. 42. 0. 0. 0. 0. 0.]
[ 0. 0. 0. 0. 0. 0. 0. 42. 42. 42. 0. 0.]
[ 0. 42. 0. 42. 0. 0. 0. 0. 42. 0. 42. 0.]
[ 0. 0. 0. 0. 0. 0. 0. 42. 0. 0. 0. 42.]
[ 0. 0. 0. 0. 0. 42. 0. 0. 0. 42. 0. 0.]
[ 0. 0. 0. 0. 0. 0. 42. 0. 0. 0. 42. 42.]
[ 0. 0. 42. 0. 42. 0. 0. 0. 0. 0. 0. 0.]]
如果要對矩陣中的節點和邊進行特定排序,請使用networkx.indicence_matrix()的nodelist =和edgelist =可選參數。
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