28 lines
925 B
Python
28 lines
925 B
Python
import math
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print("===== 题目3 向量运算 =====")
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A = [3, 4]
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B = [1, 2]
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A_plus_B = [a + b for a, b in zip(A, B)]
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print(f"A + B = {A_plus_B}")
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two_A = [2 * a for a in A]
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print(f"2 * A = {two_A}")
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norm_A = math.sqrt(sum(x**2 for x in A))
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print(f"A的模长 = {norm_A}")
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print("\n===== 题目4 点积 & 余弦相似度 =====")
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A1 = [1, 2, 3]
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B1 = [4, 5, 6]
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dot1 = sum(a*b for a, b in zip(A1, B1))
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norm_A1 = math.sqrt(sum(x**2 for x in A1))
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norm_B1 = math.sqrt(sum(x**2 for x in B1))
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cos1 = dot1 / (norm_A1 * norm_B1)
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print(f"A1·B1 点积 = {dot1}")
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print(f"A1、B1 余弦相似度 = {cos1:.4f}")
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A2 = [1, 0]
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B2 = [0, 1]
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dot2 = sum(a*b for a, b in zip(A2, B2))
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norm_A2 = math.sqrt(sum(x**2 for x in A2))
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norm_B2 = math.sqrt(sum(x**2 for x in B2))
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cos2 = dot2 / (norm_A2 * norm_B2)
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print(f"\nA2·B2 点积 = {dot2}")
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print(f"A2、B2 余弦相似度 = {cos2}")
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print("原因：两向量正交（夹角90°），余弦值为0") |