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34 lines
671 B
Python
34 lines
671 B
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_Ch6_01.py
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import numpy as np
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A = np.array([[1, 2, 3, 0, 0],
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[4, 5, 6, 0, 0],
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[0, 0, 0, -1, 0],
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[0, 0 ,0, 0, 1]])
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# NumPy array slicing
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A_1_1 = A[0:2,0:3]
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A_1_2 = A[0:2,3:]
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# A_1_2 = A[0:2,-2:]
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A_2_1 = A[2:,0:3]
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# A_2_1 = A[-2:,0:3]
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A_2_2 = A[2:,3:]
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# A_2_2 = A[-2:,-2:]
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# Assemble a matrix from nested lists of blocks
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A_ = np.block([[A_1_1, A_1_2],
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[A_2_1, A_2_2]])
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