matplotlib 習題

11.1

# -*- coding: utf-8 -*-
"""
Created on Tue May 29 19:34:16 2018

@author: 12046
"""
import numpy as np
import scipy
import matplotlib.pyplot as plt

def f(x):
    return (np.sin(x-2)**2)*(np.e**(-(x**2)))
x = np.linspace(0,2,1000)
y = f(x)
plt.plot(x,y)
plt.xlabel('x')
plt.ylabel('y=f(x)')
plt.title(r'$f(x) = \mathrm{sin}^2(x-2)*{e}^{-x^2}$')
plt.savefig('a.jpg')

輸出圖像

11.2

# -*- coding: utf-8 -*-
"""
Created on Tue May 29 20:09:29 2018

@author: 12046
"""

import numpy as np
import scipy
import matplotlib.pyplot as plt

X=np.random.randn(20,10)*np.random.randint(1,10)
z=np.random.normal(0,1,size=(20,1))
b1=np.random.rand(10,1)
y=np.dot(X,b1)+z
b2=np.array(np.linalg.lstsq(X,y,rcond=-1)[0])
x=np.linspace(1,10,10)
plt.scatter(x,b1,c='r',marker='x',label='True b')
plt.scatter(x,b2,c='b',marker='o',label='Estimated b')
plt.xlabel('index')    
plt.ylabel('value')  
plt.title('Execise 11.2')  
plt.legend()
plt.savefig('a.jpg')

輸出圖像

11.3

# -*- coding: utf-8 -*-
"""
Created on Tue May 29 20:31:11 2018

@author: 12046
"""

import numpy as np  
import matplotlib.pyplot as plt  
import scipy

z = np.random.normal(0, 1, 10000)  
kernel = scipy.stats.gaussian_kde(z)  

x= np.linspace(-4,4,1000)  
  
plt.hist(z, 25,rwidth=0.8,normed = True,color='orange')  
plt.plot(ind, x.evaluate(ind),label='kde')  
plt.title('Execise 11.3')    
plt.savefig('a.jpg')