Vectorization and Parallelization of Algorithms for Selection and Reconstruction of J/ψ → e +e - Decaysin Real Time of the CBM Experiment

The measurements of J/ψ decays is one of the key goals of the CBM experiment. The technique of J/ψ registration in its dielectron channel has been developed, which includes a chain of methods of trajectories and momentum reconstruction of charged particles with STS, electron/positron identification with RICH, TRD and TOF, as well as construction of the J/ψ-candidates and their characteristics using the KFParticle package. Taking into account that selection and reconstruction decays of J/ψ → e +e - are planned to be carried out in real time of the CBM experiment, the used methods and algorithms should be not only effective but also fast. In this paper the time-consuming estimation of the existing algorithms based on their acceleration via code vectorization by means of SIMD instructions and parallelization between the processor cores that are implemented using OpenMP, OpenCL software environments and TBB library has been carried out. This analysis allowed to establish weak points in this chain, which are under investigation, as well as offer a fast and efficient parallel algorithm for the identification of the charged particles with TRD based on the ωn k criterion.

multivariate analysis, CBM experiment, selection of J/ψ → e e decays, parallel computation, SIMD instructions