Hello Fil,
Generally, division is like multiplying by the inverse of the divisor. For
vectors, the inverse is actually a pseudoinverse or generalized
inverse<http://en.wikipedia.org/wiki/Generalized_inverse>.
In this case,
a / b = a * pinv(b)
where
julia> pinv(b)
1x3 Array{Float64,2}:
0.0519481 0.0649351 0.0779221
julia> pinv(b) * b
1-element Array{Float64,1}:
1.0
julia> a * pinv(b) # the outer product of a and pinv(b)
3x3 Array{Float64,2}:
0.0519481 0.0649351 0.0779221
0.103896 0.12987 0.155844
0.155844 0.194805 0.233766
Cheers!
Kevin
On Tue, Feb 4, 2014 at 9:19 PM, Fil Mackay <[email protected]>wrote:
> Can anyone explain what's going on here? :)
>
> julia> a = [1,2,3]
> 3-element Array{Int64,1}:
> 1
> 2
> 3
>
> julia> b = [4,5,6]
> 3-element Array{Int64,1}:
> 4
> 5
> 6
>
> julia> a / b
> 3x3 Array{Float64,2}:
> 0.0519481 0.0649351 0.0779221
> 0.103896 0.12987 0.155844
> 0.155844 0.194805 0.233766
>
> I get the principle of how two vectors (3x) lead to a matrix (3x3) result
> - but the actual values are a mystery?
>
>
