[Yt-dev] Smoothing grid change

[Matthew Turk]

Hi all,

Nicholas Earl reported a problem with his simulations -- 400x200x200
-- that resulted in a breakage in the smoothed covering grid, used for
ghost zone and vertex centered data generation.  In r1679 I applied a
fix for this to the yt trunk, changing the rounding method for
calculation of the extents of a covering grid from "ceil" to "rint".
I investigated his data and what was happening was simply a precision
bug causing the ceil to go over, where I believed when I wrote the
code it would always be epsilon below the desired value.

This should only affect generation of ghost zones for L=0 grids; if
any of you happen to run volume renderings that die on getting vertex
centered data from L=0 grids, please let me know immediately and we'll
try to fix it in a more robust fashion.

-Matt