[Nek5000-users] Using an external file for forcing in 'ffx'

[nek5000-users at lists.mcs.anl.gov]

Hey everyone,

Just following up on this question. Could really use some suggestion.

Thanks,
Saikat

Saikat Mukherjee,
PhD Student,
Paul Research Group - http://www.me.vt.edu/mpaul/
Engineering Science and Mechanics,
Virginia Tech.

On Wed, Jul 11, 2018 at 11:34 AM, Saikat Mukherjee <msaikat6 at vt.edu> wrote:

> Hey All,
>
> I have been stuck in this problem for a while now but I think it should be
> simple and probably you can tell where I am going wrong.
>
> - So I have a forcing function on a finite difference X-Y grid, which I am
> reading in as a text file in the 'userdat2' subroutine.
>
> - I am then parallelizing it using a previous suggestion by Paul, here is
> a snippet of the routine.
>
> ------------------------------------------------------------
> --------------------------------------------
>
>      subroutine usrdat2
>
>
>       include 'SIZE'
>
>       include 'TOTAL'
>
>        double precision :: my_array(651)
>
>        integer m
>
>         common /myarray/ my_array
>
>
>         parameter (my_array_size=651)
>
>
>         real  work(my_array_size)
>
>
>
>         n = my_array_size
>
>
>         call rzero(my_array,n)
>
>         call rzero(work,n)
>
>
>         if (nid.eq.0) then
>
>           open (unit=49,file='fint41.txt')
>
>              do k = 1,n
>
>                 read(49,*) my_array(k)
>
>              enddo
>
>           close(49)
>
>         endif
>
>
>          call gop(my_array,work,'+  ',n)   !  Sum over all processors
>
>
>       return
>
>       end
> ------------------------------------------------------------
> ---------------------------------------------
>
> - Next I am interpolating this forcing function to the GLL grid points in
> the userf routine, by a piecewise linear interpolant, here's how,
>
> ------------------------------------------------------------
> ----------------------------------------------
>
>      subroutine userf  (ix,iy,iz,ieg)
>
>
>       include 'SIZE'
>
>       include 'TOTAL'
>
>       include 'NEKUSE'
>
>       EQUIVALENCE    (prandtl,param(2))
>
>
>          double precision :: my_array(651)
>
>          double precision :: shaped_array(31,21)
>
>          real new_array(nx1,ny1,nz1,nelv)
>
>          double precision :: xin(21),yin(31)
>
>          double precision :: xn(nx1*ny1*nelv),yn(nx1*ny1*nelv)
>
>          double precision :: fo(nx1*ny1*nelv)
>
>          integer i,j,k,l,p,q
>
>          integer e,eg
>
>          common /myarray/ my_array
>
>
>          open(16,file='xin.txt')
>
>          do p=1,21
>
>          read(16,*) xin(p)
>
>          end do
>
>          close(16)
>
>
>          open(12,file='yin.txt')
>
>          do q=1,31
>
>          read(12,*) yin(q)
>
>          end do
>
>          close(12)
>
>
>          shaped_array = reshape(my_array,(/31,21/))
>
>
>          do i=1,nx1*ny1*nelv
>
>          xn(i) = xm1(i,1,1,1)
>
>          yn(i) = ym1(i,1,1,1)
>
>          end do
>
>          call pwl_interp_2d(31,21,yin,xin,shaped_array,nx1*ny1*nelv,yn,xn,
> fo)
>
>         new_array=reshape(fo,(/nx1,ny1,nz1,nelv/))
>
>
>                  do e=1,nelv
>
>                       eg = lglel(e)
>
>                       ffx = new_array(ix,iy,iz,eg)
>
>                  end do
>
>
>          ffy = 0.0
>
>          ffz = 0.0
>
>
>       return
>
>       end
>
>
> ------------------------------------------------------------
> ------------------------------------------------------------
> ---------------
>
> This is a test domain I made, with 6 elements. It seems to be working when
> I am using only 1 core, i.e., in series. In parallel, it seems to be giving
> me a different flowfield. My actual domain has 252 elements which I intend
> to parallelize with 48 cores. So would like to ask you how to proceed. I
> think I am close but I am slightly confused about part of the code that I
> have made red.
>
> When I am trying this in my actual domain, I get an error, "Segmentation
> fault occurred." I think the key here is parallelization and identifying
> the elements correctly which I am not sure I am doing right. Thanks for
> reading this lengthy email. Will be eager to hear from you.
>
> Thanks,
> Saikat
>
>
>
>
>
>
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