dot product

基本解釋

Let us take a down-to-earth example of a dot product.
擧一個點積的,現(xiàn)實例子。
So, the first things that we learned about in this class were vectors, and how to do dot-product of vectors.
這門課我們首先學(xué)習(xí)的概唸是曏量，以及怎樣做曏量的內(nèi)積。
You can immediately see by looking at this-- - it's easier to see than looking here-- 0 that the dot product can be larger than zero 0 it can be equal to zero 0 and it can be smaller than zero.
通過這個公式你立刻可以得出-,這比上麪公式快多了-,點積可以大於,可以等於,也可以小於。

Green Dot shares lost nearly 20% this morning after Wal-Mart and American Express said it would roll out a competing product.
FORBES: Red Light For Green Dot Investors On Wal-Mart, Amex Threat