opposite vector

基本解釋

If you took the opposite vector field that contracts everything to the origin that will have negative divergence.
如果每點處取負的向量的話,就會得到負的散度了。
But it could be that, well, imagine that my vector field accidentally goes in the opposite direction then this part of the curve, while things are flowing to the left, contributes negatively to flux.
的確有可能出現(xiàn)往兩個方向流動的情況,可以想象到，這一小部分往相反方向流動，當流體向左流時，就只能算作負值了。
This value can be negative to extrude in the direction opposite the Face object's normal vector.
這個值可以為負，從而在 Face 對象的法向量的反方向上擠壓。

So the minus vector is the same vector flipped over, pointing the opposite way.
因此負矢量即為同一矢量的翻轉(zhuǎn),指向相反的方向
耶魯公開課 - 基礎物理課程節(jié)選