[Users] interpolation error

[Haas, Roland]

Hello Chia-Hui,

the error message indicates that the code tried to interpolation a
quantity to location (x,y,z)=(-157.725,-576.349,-99.2027) but that the
grid only has a size of (xmin,ymin,zmin)x(xmax,ymax,zmax) =
(-576,-576,-576)x(576,576,576) (where I made a guess for the ymax and
zmax values given that the output only shows the shape of the grid on
one MPI rank).

So the interpolation point is outside of the domain.

Depending on what caused the interpolation this could mean eg that a
tracer particle (given the function name
"DoOneRK4StepForParticleTracerET") tried to leave the domain. This is
something that needsto be fixed in the particle_tracerET thorn,
probably by making it deactivate particles that get too close to the
edge of the domain.

Yours,
Roland

> Hello,
> 
> I am using IllinoisGRMHD with the test with nsns_test.par in https://bitbucket.org/zach_etienne/wvuthorns_diagnostics/src/master/NSNS_parameter_files/  .
> 
> The simulation runs well until t~5300 and an error occurs. The error message is like this:
> 
> 
> WARNING level 1 from host nid02210 process 0
>   while executing schedule bin particle_tracerET, routine particle_tracerET::DoOneRK4StepForParticleTracerET
>   in thorn AEILocalInterp, file /global/u1/c/chlin/et/Cactus/arrangements/Numerical/AEILocalInterp/src/Lagrange-tensor-product/../template.c:1109:
>   ->  
>    CCTK_InterpLocalUniform():
>         interpolation point is either outside the grid,
>         or inside but too close to the grid boundary!
>         (this may be caused by a global interpolation with
>          driver::ghost_size too small)
>         0-origin interpolation point number pt=0 of N_interp_points=1
>         interpolation point (x,y,z)=(-157.725,-576.349,-99.2027)
>         grid x_min(delta_x)x_max = -576(18)576
>         grid y_min(delta_y)y_max = -576(18)54
>         grid z_min(delta_z)z_max = -576(18)54
> 
> WARNING level 1 from host nid02210 process 0
>   while executing schedule bin particle_tracerET, routine particle_tracerET::DoOneRK4StepForParticleTracerET
>   in thorn particle_tracerET, file /global/u1/c/chlin/et/Cactus/arrangements/WVUThorns_Diagnostics/particle_tracerET/src/Interpolate_velocities_at_particle_positions.C:131:
>   -> interpolation screwed up  
> WARNING level 1 from host nid02210 process 1
>   while executing schedule bin particle_tracerET, routine particle_tracerET::DoOneRK4StepForParticleTracerET
>   in thorn particle_tracerET, file /global/u1/c/chlin/et/Cactus/arrangements/WVUThorns_Diagnostics/particle_tracerET/src/Interpolate_velocities_at_particle_positions.C:131:
>   -> interpolation screwed up  
> srun: error: nid02211: tasks 2-3: Exited with exit code 1
> srun: Terminating job step 21753671.0
> srun: error: nid02210: tasks 0-1: Exited with exit code 1
> 
> 
> I think maybe t can be avoided by decreasing the timestep so that the tracer particle would not move too fast to make the  interpolation screwed up but I am not sure. So what I want to ask is :
> 
>   1.  It this error can be avoided by decreasing the timestep ?
>   2.  If so, how can I  decrease the timestep in parameter file (or in other places)?
> 
> 
> Thank you.
> Best regards,
> Chia-Hui



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