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23 lines
834 B
23 lines
834 B
import Vector from './utils/vector';
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/**
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* cosine-similarity算法 计算余弦相似度
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* @param item 元素
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* @param targetItem 目标元素
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*/
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var cosineSimilarity = function cosineSimilarity(item, targetItem) {
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// 目标元素向量
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var targetItemVector = new Vector(targetItem);
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// 目标元素向量的模长
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var targetNodeNorm2 = targetItemVector.norm2();
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// 元素向量
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var itemVector = new Vector(item);
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// 元素向量的模长
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var itemNorm2 = itemVector.norm2();
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// 计算元素向量和目标元素向量的点积
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var dot = targetItemVector.dot(itemVector);
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var norm2Product = targetNodeNorm2 * itemNorm2;
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// 计算元素向量和目标元素向量的余弦相似度
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var cosineSimilarity = norm2Product ? dot / norm2Product : 0;
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return cosineSimilarity;
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};
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export default cosineSimilarity;
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