I’m trying to find the most compact/clear way to reallocate an array to a different size, keeping both boilerplate and allocations to a minimum and am looking at SOURCEd allocation. In the example, with gfortran: if the new array is longer, all data is copied from a, and the trailing elements are…

On Metcalf/Reid/Cohen it states that “if allocation is for an array, source-expr may be an array of the same rank, otherwise source-expr must be scalar”. also “because the bounds and shape of the allocated item are not taken from the source, making a clone of an array has to be done [by specifying i…

If you know they are shorter, you could apply bounds to the source: allocate(shorter(5), source = a[:5]) Or more general: allocate(shorter(new_size), source = a[:min(new_size, size(a))])

This program demonstrates an array constructor with an implied do loop and also reshape with pad to grow an array: program main implicit none real, allocatable :: x(:), y(:), z(:) integer :: i x = [10.0, 20.0] y = [x, (0.0,i=1,3)] z = reshape(x, shape=[5], pad=[0.0]) print "(*(f4.1,1x))", y,z end p…

Nice alternatives, thank you both. So I’m guessing the best option is still the sourced allocation, but unfortunately, more bound checking lines will always be necessary like pure subroutine resize(array,newsize) type(mytype), intent(inout), allocatable :: array(:) integer, inten…

Hi Federico, I was looking for how to resize an array, and I found this thread. At first I thought that using source was a neat solution, but then I started wondering: where will this memory go? Maybe at the beginning of the new array? At its end? Somewhere in the middle? I might be wrong, but this …

[image] Beliavsky: z = reshape(x, shape=[5], pad=[0.0]) I think it’s pretty clear that sourced allocation from a different-size array is non standard conforming. So, to achieve the one liner I was suggesting in the first place, @Beliavsky ’s example is the way to go. But I’m not sure about th…

This is where GitHub - PierUgit/enhanced-allocatables: Fortran allocatable arrays made resizable would be useful (the code is non-standard, it’s just there to illustrate the added value of resizable arrays).

Unfortunately, the Fortran standard does not offer the much-desired flexibility with array resizing, refilling, rebinding, and rebinding + refilling (which by merging them, I call it rebilling). Frustrated with explaining user needs to the Fortran committee members (only to have the suggestions dism…

[image] shahmoradi: Unfortunately, the Fortran standard does not offer the much-desired flexibility with array resizing, refilling, rebinding, and rebinding + refilling. Frustrated with explaining user needs to the Fortran committee members (only to have the suggestions dismissed a day after wit…

[image] rwmsu: Just about everyone that has had to deal with Fortran allocatable arrays since F90 has wanted an intrinsic procedure to resize/reallocate and a dynamically varying array (like C++ vector classes) etc. What is even more frustrating here is that implementing it both in the standa…

SOURCEd allocation for dynamic array handling

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Beliavsky April 27, 2024, 1:53pm 14

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SOURCEd allocation for dynamic array handling

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