Interpolation error

[MiriamSterl]

What can cause an InterpolationError during particle advection (with pset.execute)? I am using JITParticles and the source code says that JIT does not yet provide the context that creates such an exception, so I would be interested what possible causes could be, and how to troubleshoot this.

I am using a doubly periodic domain, where the x and y coordinates run from -L/2 to +L/2, so they are not lat/lon coordinates. The InterpolationErrors always occur when a particle reaches one of the lateral boundaries. However, the velocity fields I used for creating the FieldSet are doubly periodic (checked), and I set fieldset.add_periodic_halo(zonal=True,meridional=True) when creating the FieldSet.
The first and last columns/rows of the FieldSet are not identical; should they be, or should parcels itself 'glue them together' when given the add_periodic_halo?
Or are there any other ideas as to what could be the problem?

[VeckoTheGecko]

This tutorial notebook should help. The .add_periodic_halo() function only copies a small portion of the fieldset to the other sides of the domain (documentation), you will need to implement the periodicity directly through the use of custom kernels.

[MiriamSterl]

Thank you! I didn't realise the extra kernel was needed, but now it works perfectly :)