Julia:将1x1数组从内部乘积转换为数字 [英] Julia: convert 1x1 array from inner product to number

问题描述

从内积运算中获取数字而不是从1x1数组中获取数字的最佳方法是什么.有没有比这更好的方法了?

What is the best way to get a number out of an inner product operation, rather than a 1x1 array. Is there a better way than this:

([1 2 3]*[4 5 6]')[1]

推荐答案

如果可能的话，我不会手动制作内部产品，而是使用dot，即

If possible, I wouldn't do the inner product manually, I'd use dot, i.e.

 dot([1, 2, 3], [4, 5, 6])

我注意到您实际上并没有向量，而是有1x3个矩阵(行)，因此，如果这确实是您所需要的，则必须首先vec个它们，这是一个有点不愉快:

I've noticed that you don't actually have vectors there though, instead you have 1x3 matrices (rows), so if thats really what you have you'd have to vec them first, which is a bit unpleasant:

dot(vec([1 2 3]), vec([4 5 6]))

或者，一个人可以做

 sum([1 2 3].*[4 5 6])

这与尺寸无关.

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