23 lines
747 B
Python
23 lines
747 B
Python
import math
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A = [1, 2, 3]
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B = [4, 5, 6]
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def dot_product(v1, v2):
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return sum(x * y for x, y in zip(v1, v2))
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A_dot_B = dot_product(A, B)
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print("1. A · B =", A_dot_B)
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def vector_norm(v):
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return math.sqrt(sum(x ** 2 for x in v))
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def cosine_similarity(v1, v2):
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dot = dot_product(v1, v2)
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norm1 = vector_norm(v1)
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norm2 = vector_norm(v2)
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if norm1 == 0 or norm2 == 0:
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return 0.0
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return dot / (norm1 * norm2)
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cos_sim = cosine_similarity(A, B)
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print("2. 余弦相似度 =", round(cos_sim, 4))
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A2 = [1, 0]
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B2 = [0, 1]
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cos_sim2 = cosine_similarity(A2, B2)
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print("3. A=[1,0], B=[0,1] 的余弦相似度 =", cos_sim2)
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print(" 原因：点积为 0，说明两向量正交，夹角为 90°，所以余弦相似度为 0。") |