I just realized this behavior:

```
julia> x = [ 0. , 0. ]
2-element Array{Float64,1}:
0.0
0.0
julia> y = x
2-element Array{Float64,1}:
0.0
0.0
julia> y[1] = 1.
1.0
julia> x
2-element Array{Float64,1}:
1.0
0.0
```

`x`

and `y`

are just different names for the same vector. How do I copy a vector into another one, then?

Also, is there any style suggestion to avoid running into errors given that we could be modifying previous values of array variables this way?