Hello, I’d like to have an array which elements A[i, j] are computed from a given function f(i, j) (say f(i, j) = i + j) only when that element is used, i.e. I would not like to build the whole matrix beforehand. I was thinking of maybe writing a new type which subtypes AbstractArray, but it’s a b…

Computing array elements on call

pint February 5, 2017, 4:49pm 8

and with some hackery, we can improve. i have no clue if it is documented.

rettype(f, n) = Base.return_types(f, ntuple(_->Int, n))[1]
CalculatedArray(f, dims) = CalculatedArray{rettype(f, length(dims)), length(dims)}(f, dims)

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Computing array elements on call

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