Hello,

I am looking for the Julia equivalent of IDL’s rebin function. It basically applies a reduction function `f`

to “macro-cells” of an array. For example, a `(M₁ * N₁, M₂ * N₂, …, Mₚ * Nₚ)`

array, `x`

would be transformed into a `(N₁, N₂, …, Nₚ)`

array, `y`

, where each cell of `y`

is the result of applying `f`

to a sub-array of `x`

```
y[i₁, i₂, …, iₚ] = f(x[s₁, s₂, …, sₚ]),
```

where `sₖ`

is the following slice (hope I didn’t get indices wrong!)

```
sₖ = (iₖ * Nₖ):((iₖ+1) * Nₖ).
```

For *strided* arrays, this is quite easily achieved using a little bit of stride magic. I proposed a Python implementation of fiew years ago : https://github.com/sbrisard/rebin, based on the discussion presented here. Since then, another implementation has been published: pydl.rebin, which is probably more robust.

My question is: is there a Julia equivalent for this (extremely useful) function?

Thanks in advance!