Dear Jian, I recommend using this interface from the hemi.usr file. hth, Paul c----------------------------------------------------------------------- subroutine interp_v(uvw,xyz,n) c c evaluate velocity for list of points xyz c include 'SIZE' include 'TOTAL' real uvw(ldim,n),xyz(ldim,n) ________________________________ From: Nek5000-users <[email protected]> on behalf of [email protected] <[email protected]> Sent: Monday, September 10, 2018 10:27:15 AM To: [email protected] Subject: Re: [Nek5000-users] findpts Dear Nek, When I look at the hemi.usr, the only subroutine it calls for interpolating velocities for list of points as shown below. call interp_nfld(fpts,fwrk,ndim,pts(1),pts(1+n),pts(2*n+1), $ n,iwk,rwk,INTP_NMAX,.true.,intp_h) Could you please explain more? What I want are processor number and ix iy and iz for each point. Thanks so much for your help. Kind regards, Jian