6

I'm trying to multiply each element in a vector by itself such that it produces a matrix that is symmetric about the diagonal. For example, given this vector::

x <- 1:3

I would like to create this:

1 2 3  
2 4 6 
3 6 9

i.e:

x[1]*x[1] x[2]*x[1] x[3]*x[1]  
x[1]*x[2] x[2]*x[2] x[3]*x[2] 
x[1]*x[3] x[2]*x[3] x[3]*x[3]

Any help would be greatly appreciated. Thanks.

coding_heart
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1 Answers1

10

Like this:

x %o% x

which is a shortcut for

outer(x, x)

You can also do

 tcrossprod(x)
flodel
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