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<p>Dear all,</p>
<p>following up on last week's questions regarding a tracer particle
implementation into an evolution code I am having problems with
the function <b>CCTK_</b><b>InterpGridArrays</b>. In general, my
implementation follows the GRHydro_particle approach (in C++), and
is working in some cases. However, at some interpolation points,
the interpolation routine returns nans/infs. This error occurs
mainly for the interpolation points in refined regions and changes
when I change buffer zones, grid refinement or scheduling
options. </p>
<p>Currently, I am not finding the explicit problem, and, I observe
that my tracer particles are evolved fine in the less refined
regions (e.g., further away from the origin). For example, I may
set up 500 particles and in the first evolution step the
interpolation produces 112 nans/infs. Throughout the further
evolution, the remaining 388 particles (the ones the most far away
from the origin) are evolved fine. Therefore, I assume I am
missing something in my understanding of the interpolation
routines. Has somebody encountered similar problems or an idea
where I could direct my debugging to overcome the interpolations
to NaNs/Infs?<br>
</p>
<p>Thank you very much and my best from Valencia</p>
<p>Jens<br>
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