The function of crossprod in R puzzled me.
I would like to calculate the cross product of two vectors. According to my
text book, it defines like this:
a = (ax, ay, az)
b = (bx, by, bz)
then, the cross product of a and b is:
a X b = (ay*bz-az*by, az*bx-ax*bz, ax*by-ay*bz)
It can also write in a determinant format.
But the crossprod or tcrossprod function in R appeared not calculate the cross
product. Suppose I enter this:
> a = c(1, 2, 3)
> b = c(2, 3, 4)
> ab = crossprod(a, b)
> ab
[,1]
[1,] 20
> ab = tcrossprod(a, b)
> ab
[,1] [,2] [,3]
[1,] 2 3 4
[2,] 4 6 8
[3,] 6 9 12
Does any know how to calculate cross product in R. Or I have to write the
function myself?
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