Allocate array from array of sizes

Question

Let's say I have an array of dimensions declared like this:

integer, dimension(5) :: dims
dims = (/ 5, 6, 7, 8, 9 /)

How can I most simply use this array to allocate another array, using the elements of dims to specify the size of the respective dimensions? Say the second array is declared like this:

real, dimension(:,:,:,:,:), allocatable :: dset

Why can't I do the following?

allocate (dset(dims(:)))

I get Error: Rank mismatch in array reference when I attempt to compile.

I realize that I can do this:

allocate (dset(dims(1), dims(2), dims(3), dims(4), dims(5)))

But I'm looking for something more easily extensible.

Answer 1

You cannot write allocate(dset(dims(:))) for exactly the reason the compiler gives: they have different ranks. If you were to print shape(dims), you would see 5 on-screen; if you were to print shape(dset), you would see either 0 0 0 0 0 or 5 6 7 8 9 (depends if you allocated it or not); dims is a rank-1 array, dset is a rank-5 array.

So pretty much the only way to allocate an allocatable is via the explicit method that you feel is inextensible.