Implements the IBiCGStab (Improved Stabilized version of BiConjugate Gradient) method [YB02] in an alternative form to have only a single global reduction operation instead of the usual 3 (or 4)
Supports left and right preconditioning
KSPBCGSL for additional stabilization
Unlike the Bi-CG-stab algorithm, this requires one multiplication be the transpose of the operator before the iteration starts.
The paper has two errors in the algorithm presented, they are fixed in the code in
For maximum reduction in the number of global reduction operations, this solver should be used with
This is not supported for complex numbers.
Laurence T. Yang and Richard Brent. The improved BiCGStab method for large and sparse unsymmetric linear systems on parallel distributed memory architectures. In Proceedings of the Fifth International Conference on Algorithms and Architectures for Parallel Processing. IEEE, 2002.