MIT 6.006 Introduction to Algorithms - Lecture 2: Models of Computation, Document Distance介绍了一个计算两个文档差异的方法,如下图所示:
要计算“cosine of the angle between two vectors”,不是应该像Angle between two vectors所说的那样计算吗?
The cosine of the angle between two vectors is equal to the dot product of this vectors divided by the product of vector magnitude.
为什么在课程所介绍的方法中,“The cosine of the angle between two vectors”是“the dot product of this vectors”除以“the product of the number of words in document”?