Thanks Eric, it helps :)
----- 原始邮件 ----- 发件人: "Erik Schnetter" schnetter@gmail.com 收件人: "白济民" beki-cat@sjtu.edu.cn 抄送: "users" users@einsteintoolkit.org, "1614603292" 1614603292@qq.com 发送时间: 星期四, 2022年 4 月 28日 下午 10:28:57 主题: Re: [Users] reduction operation in CarpetIOScalar
CarpetIOScalar has two kinds of reduction operations when it comes to mesh refinement, those without the "i" prefix (for physical quantities) and those with an "i" prefix (for discretization quantities).
In particular, "isum" sums over all grid points independent of their level. This helps debug, but doesn't give information that is physically interesting. "sum" weighs each grid point by its volume, i.e. points on finer levels have a smaller weight. Adding a refined level should leave the result of "sum" unchanged. "sum" also does the right thing near symmetry boundaries.
To get the integral over the domain, use the "sum" reduction and multiply by the coarse grid spacings, i.e. the volume of one coarse grid cell.
"icount" is the number of grid points. It's usually not useful, but it's necessary internally e.g. for "norm2", and thus it can be output as well. (Why not?) "iaverage" is the (unweighted) average over all grid points. "inorm" is the unweighted norm (I don't recall which norm, probably the 2-norm).
-erik
On Sun, Apr 24, 2022 at 11:51 AM 白济民 beki-cat@sjtu.edu.cn wrote:
Hi, I'm concerning about how outscalar_reductions (e.g. one of its default, sum) in the thorn CarpetIOScalar counting values on carpet grid with multiple refinement levels. The output section in the gallery parfile nsnstohmns.par has one line reading IOScalar::outScalar_vars="...(e.g. HydroBase::rho)", so does it count values on a specified refinement level and is the counting different among different outscalar_vars? I also wonder what does "icount iaverage inorm" mean in outscalar_reductions' default. Thanks in advance for your help! Yours sincerely, Jimmy _______________________________________________ Users mailing list Users@einsteintoolkit.org http://lists.einsteintoolkit.org/mailman/listinfo/users