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https://github.com/Visualize-ML/Book4_Power-of-Matrix.git
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74 lines
1.7 KiB
Python
74 lines
1.7 KiB
Python
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###############
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# Authored by Weisheng Jiang
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# Book 4 | From Basic Arithmetic to Machine Learning
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# Published and copyrighted by Tsinghua University Press
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# Beijing, China, 2022
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###############
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# Bk4_Ch8_01.py
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import matplotlib.pyplot as plt
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import numpy as np
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def plot_shape(X,copy = False):
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if copy:
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fill_color = np.array([255,236,255])/255
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edge_color = np.array([255,0,0])/255
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else:
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fill_color = np.array([219,238,243])/255
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edge_color = np.array([0,153,255])/255
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plt.fill(X[:,0], X[:,1],
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color = fill_color,
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edgecolor = edge_color)
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plt.plot(X[:,0], X[:,1],marker = 'x',
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markeredgecolor = edge_color*0.5,
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linestyle = 'None')
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X = np.array([[1,1],
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[0,-1],
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[-1,-1],
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[-1,1]])
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# visualizations
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fig, ax = plt.subplots()
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plot_shape(X) # plot original
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# translation
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t1 = np.array([3,2]);
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Z = X + t1
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plot_shape(Z,True) # plot copy
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t2 = np.array([-3,-2]);
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Z = X + t2
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plot_shape(Z,True) # plot copy
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t3 = np.array([-2,3]);
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Z = X + t3
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plot_shape(Z,True) # plot copy
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t4 = np.array([3,-3]);
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Z = X + t4
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plot_shape(Z,True) # plot copy
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# Decorations
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ax.grid(linestyle='--', linewidth=0.25, color=[0.5,0.5,0.5])
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plt.axis('equal')
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plt.axis('square')
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plt.axhline(y=0, color='k', linewidth = 0.25)
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plt.axvline(x=0, color='k', linewidth = 0.25)
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plt.xticks(np.arange(-5, 6))
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plt.yticks(np.arange(-5, 6))
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ax.set_xlim(-5,5)
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ax.set_ylim(-5,5)
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ax.spines['top'].set_visible(False)
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ax.spines['right'].set_visible(False)
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ax.spines['bottom'].set_visible(False)
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ax.spines['left'].set_visible(False)
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plt.xlabel('$x_1$')
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plt.ylabel('$x_2$')
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