Python中的三角波形陣列

Question

生成一個由100個數組構成的數組的最有效方法是什麼？最大/最小幅度爲0.5時，形成下面三角波的形狀？

記三角波形：

Answer 1

使用發電機：

def triangle(length, amplitude): 
    section = length // 4 
    for direction in (1, -1): 
     for i in range(section): 
      yield i * (amplitude/section) * direction 
     for i in range(section): 
      yield (amplitude - (i * (amplitude/section))) * direction 

這會工作的優良被4整除的長度，你可能會錯過了爲其他3個值長度。

>>> list(triangle(100, 0.5)) 
[0.0, 0.02, 0.04, 0.06, 0.08, 0.1, 0.12, 0.14, 0.16, 0.18, 0.2, 0.22, 0.24, 0.26, 0.28, 0.3, 0.32, 0.34, 0.36, 0.38, 0.4, 0.42, 0.44, 0.46, 0.48, 0.5, 0.48, 0.46, 0.44, 0.42, 0.4, 0.38, 0.36, 0.33999999999999997, 0.32, 0.3, 0.28, 0.26, 0.24, 0.21999999999999997, 0.2, 0.18, 0.15999999999999998, 0.14, 0.12, 0.09999999999999998, 0.08000000000000002, 0.06, 0.03999999999999998, 0.020000000000000018, -0.0, -0.02, -0.04, -0.06, -0.08, -0.1, -0.12, -0.14, -0.16, -0.18, -0.2, -0.22, -0.24, -0.26, -0.28, -0.3, -0.32, -0.34, -0.36, -0.38, -0.4, -0.42, -0.44, -0.46, -0.48, -0.5, -0.48, -0.46, -0.44, -0.42, -0.4, -0.38, -0.36, -0.33999999999999997, -0.32, -0.3, -0.28, -0.26, -0.24, -0.21999999999999997, -0.2, -0.18, -0.15999999999999998, -0.14, -0.12, -0.09999999999999998, -0.08000000000000002, -0.06, -0.03999999999999998, -0.020000000000000018] 

Answer 2

您可以使用迭代器生成器以及numpy fromiter方法。

import numpy 

def trigen(n, amp): 
    y = 0 
    x = 0 
    s = amp/(n/4) 
    while x < n: 
     yield y 
     y += s 
     if abs(y) > amp: 
      s *= -1 
     x += 1 

a = numpy.fromiter(trigen(100, 0.5), "d") 

現在你有一個方波陣列。

Answer 3

要使用numpy的：

def triangle2(length, amplitude): 
    section = length // 4 
    x = np.linspace(0, amplitude, section+1) 
    mx = -x 
    return np.r_[x, x[-2::-1], mx[1:], mx[-2:0:-1]] 

Answer 4

三角是鋸齒的絕對值。

from scipy import signal 
time=np.arange(0,1,0.001) 
freq=3 
tri=np.abs(signal.sawtooth(2 * np.pi * freq * time)) 

Answer 5

生成三角波的最簡單方法是使用signal.sawtooth。注意signal.sawtooth（phi，width）接受兩個參數。第一個參數是階段，下一個參數指定對稱性。寬度= 1給出右側鋸齒，寬度= 0給出左側鋸齒，寬度= 0.5給出對稱三角形。請享用！

from scipy import signal 
import numpy as np 
import matplotlib.pyplot as plt 
t = np.linspace(0, 1, 500) 
triangle = signal.sawtooth(2 * np.pi * 5 * t, 0.5) 
plt.plot(t, triangle)