第三章课后习题3.2和3.3

zlt-2005 / 2025-02-10 / 原文

习题3.2

点击查看代码
def X(n):  
    # 差分方程的解  
    return 2 * (-1)**(n + 1)     
n_values = [0, 1, 2, 3, 4, 5]#根据需要自行调整  
for n in n_values:  
    print(f"X({n}) = {X(n)}")
print("学号:3001")

习题3.3

点击查看代码
import numpy as np 
from scipy.sparse.linalg import eigs 
import pylab as plt  
w = np.array([[0, 1, 0, 1, 1, 1],
              [0, 0, 0, 1, 1, 1],
              [1, 1, 0, 1, 0, 0],
              [0, 0, 0, 0, 1, 1],
              [0, 0, 1, 0, 0, 1],
              [0, 0, 1, 0, 0, 0]])
r = np.sum(w,axis=1,keepdims=True)
n = w.shape[0] 
d = 0.85
P = (1-d)/n+d*w/r #利用矩阵广播
w,v = eigs(P.T,1) #求最大特征值及对应的特征向量
v = v/sum(v)
v = v.real 
print("最大特征值为:",w.real)
print("归一化特征向量为:\n",np.round(v,4))
plt.bar(range(1,n+1),v.flatten(),width=0.6)
plt.show() 
print("学号:3001")