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| -rw-r--r-- | Docs/source/usage/parameters.rst | 5 |
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diff --git a/Docs/source/usage/parameters.rst b/Docs/source/usage/parameters.rst index e1cc5304e..f90ec5485 100644 --- a/Docs/source/usage/parameters.rst +++ b/Docs/source/usage/parameters.rst @@ -1223,6 +1223,11 @@ Numerics and algorithms See equations 21-23 of (`Godfrey and Vay, 2013 <https://doi.org/10.1016/j.jcp.2013.04.006>`_) and associated references for details. Defaults to `1` unless ``warpx.do_nodal = 1`` and/or ``algo.field_gathering = momentum-conserving``. + .. warning:: + + The default behavior should not normally be changed. + At present, this parameter is intended mainly for testing and development purposes. + * ``interpolation.field_gathering_nox``, ``interpolation.field_gathering_noy``, ``interpolation.field_gathering_noz`` (default: ``2`` in all directions) The order of the interpolation used with staggered grids (``warpx.do_nodal = 0``) and momentum-conserving field gathering (``algo.field_gathering = momentum-conserving``) to interpolate the electric and magnetic fields from the cell centers to the cell nodes, before gathering the fields from the cell nodes to the particle positions. High-order interpolation (order 8 in each direction, at least) is necessary to ensure stability in typical LWFA boosted-frame simulations using the Galilean PSATD or comoving PSATD schemes. This arbitrary-order interpolation is used only when the PSATD solver is used for Maxwell's equations. With the FDTD solver, basic linear interpolation is used instead. |