I would like to code an eye function that accepts an integer n and returns the n by n identity matrix. In my project, the type of n can be either integer or integer(IK). Here, IK is an integer of the parameter attribute. Imagine, for example, that IK is defined by a module that looks like the follo…

[image] zaikunzhang: The difficulty is, I do not know whether integer(IK) is identical to the default integer or not . @zaikunzhang , see the example in this thread . My suggestion will be to think like a library developer and provide generic facilities which make use of options such as integ…

kargl: Seems to be a fairly trivial function to implement. Hi @kargl . Thank you for the detailed answer. Does it work if one of int8, int16, int32, and int64 is not supported by the user’s platform?

Thank you @FortranFan for the detailed solution and explanation! [image] Faster string to double elemental subroutine str2r_rk3( r, str ) character(len=*), intent(in) :: str real(real_kinds(3)), intent(out) :: r ! Local variables integer, parameter :: WP = real_kinds(3…

[image] NormanKirkby: Size does take a kind argument so you can control the kind of your size(x. Kind=) Thank you @NormanKirkby . Yes, this would completely resolve the problem provided that I am not so lazy and careless to forget to include the kind argument almost every time.

[image] shahmoradi: Ideally, one would have to implement the function for different kinds of integers. Then the default kind or any kind associated with IK will be automatically supported because all integer kinds are supported. I totally agree. The problem is, which kinds should be included …

kargl: In the places that I have used iso_fortran_env, you would have something like use mytypes, only : ik1 => XXX, ik2 => YYY where XXX and YYY have been data mined from iso_fortran_env. Thank you @kargl for the explanation. Is there a way to do this data mining automatically so that I i…

[image] zaikunzhang: Thank you @kargl for the explanation. Is there a way to do this data mining automatically, or does the user have to do it manually? This has been discussed previously here: Portable way to check existence of ISO_FORTRAN_ENV intrinsic module - #9 by milancurcic Which Kin…

[image] certik: [image] zaikunzhang: Thank you @kargl for the explanation. Is there a way to do this data mining automatically, or does the user have to do it manually? This has been discussed previously here: [image] certik: Which Kinds are Real? Thank you @certik for pointing …

Thank everyone for the valuable input! The best solution I have seen up to now is the following (it is not by me). module eye_mod use, intrinsic :: iso_fortran_env, only : INTEGER_KINDS implicit none integer, parameter :: IK = INTEGER_KINDS(1) ! Only an example. It can be whatever kind that is v…

Here is a standalone generic subroutine and function implementation of the Eye matrix for all kinds of complex and real types (but only with default input integer kind in the function interface. Any non-default integer has really no practical storage or performance advantage from my perspective). Th…

An `eye` function that accepts the default integer and another integer kind simultaneously

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certik November 9, 2021, 12:06am 19

This has been discussed previously here:

Portable way to check existence of ISO_FORTRAN_ENV intrinsic module - #9 by milancurcic
Which Kinds are Real?
Discussion on Fortran's type-kind distinction
Best way to declare a double precision in Fortran?

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An `eye` function that accepts the default integer and another integer kind simultaneously

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