Question about Calculation of Cross Product
Try library(pracma) ? cross Michael Weylandt
On Thu, Nov 3, 2011 at 1:17 AM, ?? <rz1991 at foxmail.com> wrote:
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? ? ? ? ?[[alternative HTML version deleted]]
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