This repository implements accelerated cyclic reduction (ACR), a distributed-memory fast direct solver for rank-compressible block tridiagonal linear systems arising from the discretization of elliptic operators, developed here for three dimensions. Algorithmic synergies between cyclic reduction and hierarchical matrix arithmetic operations result in a solver that has log-linear arithmetic complexity and memory footprint. Further information of the method can be found at A Direct Elliptic Solver Based on Hierarchically Low-Rank Schur Complements
Usage information can be found in ./testFolder