Porting of the DBCSR Library for Sparse Matrix-Matrix Multiplications to Intel Xeon Phi Systems

Multiplication of two sparse matrices is a key operation in the simulation of the electronic structure of systems containing thousands of atoms and electrons. The highly optimized sparse linear algebra library DBCSR (Distributed Block Compressed Sparse Row) has been specifically designed to efficiently perform such sparse matrix-matrix multiplications. This library is the basic building block for linear scaling electronic structure theory and low scaling correlated methods in CP2K. It is parallelized using MPI and OpenMP, and can exploit GPU accelerators by means of CUDA. We describe a performance comparison of DBCSR on systems with Intel Xeon Phi Knights Landing (KNL) processors, with respect to systems with Intel Xeon CPUs (including systems with GPUs).