[Nek5000-users] Monitor points, location probe

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

I need to monitor scalar gradient (scalar is modelled with temperature as in examples.pdf).
So I have inserted in USERCHK
      parameter (lt=lx1*ly1*lz1*lelt)
      common /ilgrad/ dtdx(lt),dtdy(lt),dtdz(lt)
      if ((mod(istep,iostep).eq.0).and.(istep.ge.iostep)) then
      call gradm1(dtdx,dtdy,dtdz,t)
      endif
      call hpts()

Next there are two options to monitor a quantity
1. in .rea file like
  ***** HISTORY AND INTEGRAL DATA *****
 001   POINTS.  Hcode, I,J,H,IEL
 UV PT    H      3    3    1    1

But I dont know how to tell it that I want instead of UV, and also I don't know how to calculate number of element IEL from physical location.

2. hpts.in file
you can input physical coordinates of a location, but in hpts.out only the following variables 
# time  vx  vy  [vz]  pr  T  PS1  PS2  ...
are being stored.

So I tried to modify nek5000/branches/mvmesh/postpro.f in the following way:
first I put 
      parameter (lt=lx1*ly1*lz1*lelt)
      common /ilgrad/ dtdx(lt),dtdy(lt),dtdz(lt)
in the beginning of subroutine hpts

and later in this routine changed the code:


      ! pack working array
      nflds = 0
      if(ifvo) then
        call copy(wrk(1,1),vx,ntot)
        call copy(wrk(1,2),vy,ntot)
        if(if3d) call copy(wrk(1,3),vz,ntot)
        nflds = ndim
      endif
      if(ifpo) then
        nflds = nflds + 1
        call copy(wrk(1,nflds),pm1,ntot)
      endif
      if(ifto) then
        nflds = nflds + 1
        call copy(wrk(1,nflds),t,ntot)
      endif
        nflds = nflds + 1			!!!!!!!!!inserted
        call copy(wrk(1,nflds),dtdx,ntot)	!!!!!!!!!inserted
        nflds = nflds + 1			!!!!!!!!!inserted
        call copy(wrk(1,nflds),dtdy,ntot)	!!!!!!!!!inserted
      do i = 1,ldimt
         if(ifpsco(i)) then
           nflds = nflds + 1
           call copy(wrk(1,nflds),T(1,1,1,1,i+1),ntot)
         endif
      enddo
      
It was compiled without problem, but running the program yielded no change in hpts.out,
as before there are only 5 columns
# time  vx  vy  [vz]  pr  T  

Please help