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Verification check of thread safety v004
Description This verification check examines whether a model called in parallel by multiple threads gives the same results as when called sequentially. A number `num_configs` (preset in the code) of configurations is generated, each containing a different number of atoms based on a randomly distorted, periodic, face-centered cubic (fcc) structure containing a random distribution of all atoms supported by the model. Configurations used for testing are provided as auxiliary files. The energy and forces for each configuration are computed in sequence. Then the calculations are repeated using Python multithreading with `num_configs` threads and the Global Interpreter Lock (GIL) released to ensure true parallelism. Each thread possesses its own copy of memory related to the calculation. The threaded calculations are repeated `num_cycles` times (preset in the code) with the configurations randomly distributed to the threads to create many varying opportunities for collisions. To pass the test, the total energy and the forces on all atoms for a given configuration obtained in all cycles must be be identical to those obtained in the sequential calculation. Failure of this verification check implies that the model is inappropriately storing information in persistent (static) memory during or between calls. Passing this verification check provides some assurance the the model is thread-safe, but it is NOT a guarantee due to the inherent randomness of race conditions in unsafe code. To be certain, the model code would need to be studied and analyzed carefully.


Changes in version 004:
* Update syntax for latest ASE calculator to release GIL
* Use context manager for ASE calculator in single-threaded stage to ensure model destroy is called (in case the model has global variables managed by its create/destroy functions that could impact thread safety)
* Minor reformatting
A statement of applicability provided by the contributor, informing users of the intended use of this KIM Item.
Contributor Ellad B. Tadmor
Maintainer Ellad B. Tadmor
Published on KIM 2020
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Funding Not available
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DOI 10.25950/435d6538
KIM Item TypeVerification Check
Properties as defined in kimspec.edn.
KIM API Version2.0
Simulator Name
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Programming Language(s)
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100.00% Python
Previous Version ThreadSafety__VC_881176209980_003

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