I get the fortran runtime warning "An array temporary was created" when running my code (compiled with gfortran) and I would like to know if there is a better way to solve this warning.
My original code is something like this:
allocate(flx_est(lsign,3))
allocate(flx_err(lsign,3))
do i=1,lsign
call combflx_calc(flx_est(i,:),flx_err(i,:))
enddo
Inside the subroutine I define the variables like this:
subroutine combflx_calc(flx_est,flx_err)
use,intrinsic :: ISO_Fortran_env, only: real64
implicit none
real(real64),intent(inout) :: flx_est(3),flx_err(3)
flux_est and flx_err vectors may change inside the subroutine depending on several conditions and I need to update their values accordingly.
Fortran does not seem to like this structure. I can solve it defining temporary variables:
tmp_flx_est=flx_est(i,:)
tmp_flx_err=flx_err(i,:)
call combflx_calc(tmp_flx_est,tmp_flx_err)
flx_est(i,:)=tmp_flx_est
flx_err(i,:)=tmp_flx_err
But it seems to me quite a silly way to fix it.
As you may see I'm not an expert with Fortran, so any help is more than welcome.
One way is to pass an assumed shape array
real(real64),intent(inout) :: flx_est(:),flx_err(:)
the other is to exchange the dimensions of your array, so that you can pass a contiguous section of the 2D array.
call combflx_calc(flx_est(:,i),flx_err(:,i))
The problem is that the explicit size dummy arguments of your procedure (var(n)) require contiguous arrays. The assumed shape arrays can have some stride.