循环卷积python代码

 1 # -*- coding:utf-8 -*-
 2 import numpy as np
 3 import matplotlib.pyplot as plt
 4 #x1=[6,5,6,3,5,7,0,1]
 5 #x2=[7,1,2,9,4,3,20,1,2,3,5]
 6 x1=[1,2,3,4]
 7 x2=[1,1,1,1,0,0,0,0]
 8 
 9 #确定循环卷积序列的长度N
10 N=max(len(x1),len(x2))
11 
12 #补0
13 if len(x1)>len(x2):
14     for i in range(len(x2),len(x1)):
15         x2.append(0)
16 else:
17     for i in range(len(x1),len(x2)):
18         x1.append(0)
19 
20 #序列x1周期延拓，以y轴为对称轴对称变换，截取0~N-1的序列
21 temp_x1=[]
22 temp_x1.append(x1[0])
23 for i in range(1,len(x1)):
24     temp_x1.append(x1[N-i])
25 print(temp_x1)
26 
27 #针对变化后的x1进行0~N-1的循环移动，获得一个N*N的cycle_matrix矩阵
28 x1=temp_x1
29 cycle_matrix=[]
30 cycle_matrix.append(x1)
31 for step in range(1,N):
32     temp=[]
33     for i in range(0,N):
34         temp.append(0)
35     for i in range(0,N):
36         temp[(i+step)%N]=x1[i]
37     cycle_matrix.append(temp)
38 print(cycle_matrix)
39 
40 #矩阵相乘，获得循环卷积结果序列result
41 cycle_matrix=np.array(cycle_matrix)
42 x2=np.array(x2)
43 result=np.matmul(cycle_matrix,np.transpose(x2))
44 result=list(result)
45 nnum=[]
46 for i in range(0,N):
47     nnum.append(i)
48 print(result,nnum)
49 
50 #画图
51 plt.bar (nnum,result,width=0.04,color =‘r‘)
52 plt.xlabel (‘n‘)
53 plt.ylabel (‘y‘)
54 plt.title (‘result‘)
55 plt.show ()