Alamode uses the Simplified Linear Equation Solver (SLES) library form the Portable Extensible Toolkit for Scientific Computation (PETSc) as its linear equation solver. This provides access to a wide range of preconditioned iterative algorithms for solving linear systems of equations.
Most linear systems can be solved with -slesPreconditioning ilu -slesAccelerator bcgs, but some may require a direct factorization.