Assembly of stiffness matrices via atomics

Finite element methods require the composition of the global stiffness matrix from finite element contributions. The composition process combines the computation of element stiffness matrices and their assembly into the global stiffness matrix, which is sparse and often symmetric. In this paper we consider the assembly process of the global stiffness matrix and explore different algorithms and their efficiency on shared memory systems using C++. A key aspect of our investigation is the use of atomic synchronization primitives. Furthermore, we propose a new storage format for sparse matrices and compare its performance with the compressed row storage format.