| -ksp_richardson_scale <scale, default=1.0> | - see KSPRICHARDSON | |
| -ksp_gmres_restart <restart, default=40> | - see KSPGMRES | |
| -ksp_hpddm_type <type, default=gmres> | - any of gmres, bgmres, cg, bcg, gcrodr, bgcrodr, or bfbcg | |
| -ksp_hpddm_deflation_tol <eps, default=-1.0> | - tolerance when deflating right-hand sides inside block methods (no deflation by default, only relevant with block methods) | |
| -ksp_hpddm_enlarge_krylov_subspace <p, default=1> | - split the initial right-hand side into multiple vectors (only relevant with nonblock methods) | |
| -ksp_hpddm_orthogonalization <type, default=cgs> | - any of cgs or mgs, see KSPGMRES | |
| -ksp_hpddm_qr <type, default=cholqr> | - distributed QR factorizations with any of cholqr, cgs, or mgs (only relevant with block methods) | |
| -ksp_hpddm_variant <type, default=left> | - any of left, right, or flexible (this option is superseded by KSPSetPCSide()) | |
| -ksp_hpddm_recycle <n, default=0> | - number of harmonic Ritz vectors to compute (only relevant with GCRODR or BGCRODR) | |
| -ksp_hpddm_recycle_target <type, default=SM> | - criterion to select harmonic Ritz vectors using either SM, LM, SR, LR, SI, or LI (only relevant with GCRODR or BGCRODR) | |
| -ksp_hpddm_recycle_strategy <type, default=A> | - generalized eigenvalue problem A or B to solve for recycling (only relevant with flexible GCRODR or BGCRODR) |
| 1980 | - The Block Conjugate Gradient Algorithm and Related Methods. O'Leary. Linear Algebra and its Applications. | |
| 2006 | - Recycling Krylov Subspaces for Sequences of Linear Systems. Parks, de Sturler, Mackey, Johnson, and Maiti. SIAM Journal on Scientific Computing | |
| 2013 | - A Modified Block Flexible GMRES Method with Deflation at Each Iteration for the Solution of Non-Hermitian Linear Systems with Multiple Right-Hand Sides. Calandra, Gratton, Lago, Vasseur, and Carvalho. SIAM Journal on Scientific Computing. | |
| 2016 | - Block Iterative Methods and Recycling for Improved Scalability of Linear Solvers. Jolivet and Tournier. SC16. | |
| 2017 | - A breakdown-free block conjugate gradient method. Ji and Li. BIT Numerical Mathematics. |