I stumbled across the function *circshift* today in the Julia
documentation. I have a use case for a slight extension of that function. I
wonder whether it might be useful for others.
Assume you are generating vectors iteratively and you store those vectors
as the columns of a matrix. Let's say you only need the last N generated
vectors and thus the matrix has N columns.
If the number of iterations exceed N then you need to shift the columns to
the left and overwrite the right-most column. A very crude implementation
would be:
function circupdate(A, x)
A = circshift(A, [0; -1])
for i = 1:size(A, 1)
A[i, end] = x[i]
end
return A
end
where x is the newest vector you are storing in the matrix A.
Considering memory usage I was thinking on a *circshift!* function which
overwrites the input and adding an optional argument to facilitate what I
tried to accomplish with the crude code above.
