Python3 用matplotlib绘制sigmoid函数的案例

时间:2022-09-01 18:15:40

我就废话不多说了,大家还是直接看代码吧~

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import matplotlib.pyplot as plt
import numpy as np
def sigmoid(x):
  # 直接返回sigmoid函数
  return 1. / (1. + np.exp(-x))
 
def plot_sigmoid():
  # param:起点,终点,间距
  x = np.arange(-8, 8, 0.2)
  y = sigmoid(x)
  plt.plot(x, y)
  plt.show()
 
if __name__ == '__main__':
  plot_sigmoid()

如图:

Python3 用matplotlib绘制sigmoid函数的案例

补充知识:python:实现并绘制 sigmoid函数,tanh函数,ReLU函数,PReLU函数

如下所示:

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# -*- coding:utf-8 -*-
from matplotlib import pyplot as plt
import numpy as np
import mpl_toolkits.axisartist as axisartist
 
def sigmoid(x):
  return 1. / (1 + np.exp(-x))
 
def tanh(x):
  return (np.exp(x) - np.exp(-x)) / (np.exp(x) + np.exp(-x))
 
def relu(x):
  return np.where(x<0,0,x)
 
def prelu(x):
  return np.where(x<0,0.5*x,x)
 
def plot_sigmoid():
  x = np.arange(-10, 10, 0.1)
  y = sigmoid(x)
  fig = plt.figure()
  # ax = fig.add_subplot(111)
  ax = axisartist.Subplot(fig,111)
  ax.spines['top'].set_color('none')
  ax.spines['right'].set_color('none')
  # ax.spines['bottom'].set_color('none')
  # ax.spines['left'].set_color('none')
  ax.axis['bottom'].set_axisline_style("-|>",size=1.5)
  ax.spines['left'].set_position(('data', 0))
  ax.plot(x, y)
  plt.xlim([-10.05, 10.05])
  plt.ylim([-0.02, 1.02])
  plt.tight_layout()
  plt.savefig("sigmoid.png")
  plt.show()
 
def plot_tanh():
  x = np.arange(-10, 10, 0.1)
  y = tanh(x)
  fig = plt.figure()
  ax = fig.add_subplot(111)
  ax.spines['top'].set_color('none')
  ax.spines['right'].set_color('none')
  # ax.spines['bottom'].set_color('none')
  # ax.spines['left'].set_color('none')
  ax.spines['left'].set_position(('data', 0))
  ax.spines['bottom'].set_position(('data', 0))
  ax.plot(x, y)
  plt.xlim([-10.05, 10.05])
  plt.ylim([-1.02, 1.02])
  ax.set_yticks([-1.0, -0.5, 0.5, 1.0])
  ax.set_xticks([-10, -5, 5, 10])
  plt.tight_layout()
  plt.savefig("tanh.png")
  plt.show()
 
def plot_relu():
  x = np.arange(-10, 10, 0.1)
  y = relu(x)
  fig = plt.figure()
  ax = fig.add_subplot(111)
  ax.spines['top'].set_color('none')
  ax.spines['right'].set_color('none')
  # ax.spines['bottom'].set_color('none')
  # ax.spines['left'].set_color('none')
  ax.spines['left'].set_position(('data', 0))
  ax.plot(x, y)
  plt.xlim([-10.05, 10.05])
  plt.ylim([0, 10.02])
  ax.set_yticks([2, 4, 6, 8, 10])
  plt.tight_layout()
  plt.savefig("relu.png")
  plt.show()
 
def plot_prelu():
  x = np.arange(-10, 10, 0.1)
  y = prelu(x)
  fig = plt.figure()
  ax = fig.add_subplot(111)
  ax.spines['top'].set_color('none')
  ax.spines['right'].set_color('none')
  # ax.spines['bottom'].set_color('none')
  # ax.spines['left'].set_color('none')
  ax.spines['left'].set_position(('data', 0))
  ax.spines['bottom'].set_position(('data', 0))
  ax.plot(x, y)
  plt.xticks([])
  plt.yticks([])
  plt.tight_layout()
  plt.savefig("prelu.png")
  plt.show()
 
if __name__ == "__main__":
  plot_sigmoid()
  plot_tanh()
  plot_relu()
  plot_prelu()

以上这篇Python3 用matplotlib绘制sigmoid函数的案例就是小编分享给大家的全部内容了,希望能给大家一个参考,也希望大家多多支持服务器之家。

原文链接:https://blog.csdn.net/hiudawn/article/details/79876726