ave/spatial for just a specific region

Hi LAMMPS community,

Is there a way to write out the averages for just a specific region? I know that ave/spatial with region keywords does a similar thing but if the specified region is not exactly coincident with a bin then it’s split between the number of bins that cover the region and reported in those bins…but what I’m looking for is just one set of averaged values for the the specified region, I’d appreciate any input helping me to handle this.


Hi Kasra, you can try the atc package using the hardy mode. If you can get the mesh to conform to the region you're interested in, it shouldn't be a problem.

Thanks Jeremy, I took a look at the fix but I couldn’t quite understand how I can use it. Would you give me an example because, I see “transfer” as a keyword in the examples on fix atc page but it’s not among the allowed keywords defined for this fix, so I’m confused would you help me more.


See the variable rmask() function which is 0 for atoms not
in the region. If you use a variable with rmask as an arg to fix ave/time
or fix ave/spatial then you can get only the atoms in the region.