In the LHCb experiment, a wide variety of Monte Carlo simulated samples need to be produced for the experiment’s physics programme. LHCb has a centralised production system for simulating, reconstructing and processing collision data, which runs on the DIRAC backend on the WLCG.
To cope with a large set of different types of sample, requests for simulation production are based on a concept of “models” (templates) for each data-taking period, with variations for different generators and fast-simulation techniques. Request are then customised via pre-defined configuration per type of event (i.e. decay). This allows requests to be created and handled efficiently on a world-wide distributed system by a small team of people. However, maintenance and regular updates of these models, as well as the creation of bespoke requests (e.g. with filtered output) can be time-consuming tasks, prone to human error.
We present LbMCSubmit: a new scriptable submission system which generates the necessary requests from a parametrisation of the desired samples. The numerous request models are replaced by a set of rules for creating requests, thus ensuring consistency and reducing the workload required for their maintenance. Support for common use-cases is built-in, while also allowing for fine-grained customisation as needed.
Data-files specifying production requests are collected in a GitLab repository, then tested and submitted by CI jobs, using a shared infrastructure with the existing Analysis Productions package. LbMCSubmit may also be used at the command-line for running local tests or submitting user jobs (e.g. for generator tuning studies) to DIRAC.
LbMCSubmit results in a significant reduction in the time spent maintaining and updating request models, preparing and submitting the requests themselves, as well as ensuring that newly released configuration files (e.g. for new decay types) are immediately available in production.
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