[Developers] How about changing avoid_origin* restricted ?
Erik Schnetter
schnetter at cct.lsu.edu
Sat Apr 14 09:09:52 CDT 2007
On Apr 14, 2007, at 07:15:01, jtao at cct.lsu.edu wrote:
> It is sometime necessary to check if the grid contains origin.
> If avoid_origin parameters can be accessed directly,
> one doesn't have to do explicit checking. Is it ok to change
> those avoid_origin parameters restricted ?
I'm afraid that this would not work in the general case. Even
CartGrid3D ignores the avoid_origin parameter under certain
circumstances. CoordBase does not take them into account. With mesh
refinement, avoid_origin describes only the coarsest grid, and finer
grids can have different behaviour. avoid_origin is meant for a
human being to give instructions to CartGrid3D. It is not a good
idea to use it to draw conclusions about how the grid is laid out in
the end.
Instead, you can calculate the quantity
CCTK_REAL nx0 = (0.0 - CCTK_ORIGIN_SPACE(0)) / CCTK_DELTA_SPACE(0)
and test whether it is integer or not:
if (fabs (nx0 - floor(nx0)) < 0.01) /* grid point at origin */
else if (fabs (nx0 - floor(nx0) + 0.5) < 0.01) /* staggered about
origin */
else /* no definite relation */
-erik
--
Erik Schnetter <schnetter at cct.lsu.edu>
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