Opened 4 months ago

Last modified 4 months ago

#2177 new defect

CarpetInterp tree_search fails when using Carpet with manual topology specified

Reported by: yosef@… Owned by:
Priority: unset Milestone:
Component: Other Version: development version
Keywords: Cc:


While running a unigrid simulation in Carpet, I ran into an issue with interpolation. The CarpetInterp tree_search algorithm fails when I used Carpet::processor_topology = "manual"

Is this expected? Setting CarpetInterp::tree_search = false
seems to make the problem go away.

This is the reported error when tree_search = yes

Inconsistent search result from find_location_tree for interpolation point #1626 at [0.043412,-0.246202,3.0151e-17] of patch #0 is not on any component

I attached a parfile showing the issue.

Attachments (1)

simple.par (4.0 KB) - added by yosef@… 4 months ago.
parfile that triggers tree_search error

Download all attachments as: .zip

Change History (5)

Changed 4 months ago by yosef@…

Attachment: simple.par added

parfile that triggers tree_search error

comment:1 Changed 4 months ago by Erik Schnetter

This is not expected, but understandable. Apparently, the manual process decomposition does not properly initialize the data structure upon which the tree search relies. Given that a manual specification is rarely used (is it?), and that there is a work-around, this might not be corrected in the near term.

The tree search speeds up interpolation when there are many processes. Is interpolation a bottleneck in this simulation? How many processes are you using?

comment:2 Changed 4 months ago by yosefz@…

I would expect that we wouldn't use more than 512 cores. What would be needed to properly initialize the appropriate data structures?

comment:3 Changed 4 months ago by Erik Schnetter

I assume that the process regions are initialized, but the superregions are not initialized. There should be one superregion, defining a tree structure for the actual regions.

Is interpolation actually a bottleneck in the simulation?

comment:4 Changed 4 months ago by yosef@…

Interpolation is not yet a bottleneck. The code is not yet used in any production setting. I found this issue while debugging an unrelated problem.

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