FEAST Solver Package
Current status:
 Solving Ax=ex or Ax=eBx,
A is real symmetric or complex Hermitian, B is symmetric or Hermitian positive definite.
 Two libraries: SMP version (one node), and MPI version (multinodes).
 Real/Complex and Single/Double precisions,
 All FEAST interfaces compatible with Fortran (77, 90) and C. All the FEAST interfaces require (any) BLAS and LAPACK packages.
 Source code and precompiled libraries provided for common architectures (x64).
 Reverse communication interfaces (RCI): Maximum flexibility for applicationspecific.
 Predefined driver interfaces for dense, banded, and sparse formats: Less flexibility but
easy to use ("plug and play")
 Large number of examples provided and documentation included,
 FEAST utility drivers for sparse systems included: users can provide directly their sparse systems for quick testing, timing, etc. .
Current development:
 FEAST for nonsymmetric eigenvalue problem (including nonHermitian and complex symmetric).
 NLFEAST, new scheme for solving the nonlinear eigenvector problems (e.g. for electronic structure calculations).

FEAST Algorithm
Some of the important capabilities of the FEAST algorithm described in [1]
can be outlined as follows:
 Fast convergence  FEAST converges in ~23 iterations with very high accuracy
 Naturally captures all multiplicities
 No(explicit) orthogonalization procedure
 Reusable subspace  can benefit from suitable initial guess for solving series of eigenvalue problems that are close one another
 Ideally suited for large sparse systems allows the use of iterative methods.
 the scalability of the FEAST algorithm is first and foremost dependent on the scalability of the inner
linear system solver;
 Three levels of parallelism: (i) many search interval
can be run independently (no overlap), (ii) the independent inner linear systems can be solved simultaneously on each nodes (using FEASTMPI),
(iii) within a given node, the inner system solver can be solved in parallel (currently with shared memory capability).
Current research:
