{{ message }}
Repository navigation
SimpleMPS algorithm breaks due to integer overflow of cell coordinates #2
Description
The current SimpleMPS code creates points that lie out of the expected bounding box, i.e. outside the grid coordinates. Particularly if I check all generated points for x > 0 the assertion fails, but only very randomly. I didn't debug further, but if I switch to the commented code with pool updates as defined here https://github.com/sandialabs/DeterministicMPS/blob/main/source/SimpleMPS.cpp#L124-L143 the problem vanishes.
Activity
[-]Version without pool updates generates erronous points[/-][+]Algorithm generates points outside of domain[/+]drlight-code commentedon Nov 1, 2024
The problem also crops up when using the version with pool updates, so it seems not directly related after all.
[-]Algorithm generates points outside of domain[/-][+]Algorithm generates points outside of domain due to integer overflow[/+][-]Algorithm generates points outside of domain due to integer overflow[/-][+]SimpleMPS algorithm generates points outside of domain due to integer overflow[/+]drlight-code commentedon Nov 4, 2024
I did the debugging, the problem occurs due to an integer overflow of the cell coordinates. It happens only very rarely for certain choices of random seeds, where a high number of refinements is necessary. When the error occurs here, I'm at refinement level 19. The problem appears in the
refinemethod step when the cell coordinates are doubled https://github.com/sandialabs/DeterministicMPS/blob/main/source/SimpleMPS.cpp#L353-L354Defining the cell coordinates as
size_tinstead ofintfixes the issue for me https://github.com/sandialabs/DeterministicMPS/blob/main/source/SimpleMPS.hpp#L28[-]SimpleMPS algorithm generates points outside of domain due to integer overflow[/-][+]SimpleMPS algorithm breaks due to integer overflow of cell coordinates[/+]