| -snes_ngmres_select_type<difference,none,linesearch> | - choose the select between candidate and combined solution | |
| -snes_ngmres_restart_type<difference,none,periodic> | - choose the restart conditions | |
| -snes_ngmres_candidate | - Use NGMRES variant which combines candidate solutions instead of actual solutions | |
| -snes_ngmres_m | - Number of stored previous solutions and residuals | |
| -snes_ngmres_restart_it | - Number of iterations the restart conditions hold before restart | |
| -snes_ngmres_gammaA | - Residual tolerance for solution select between the candidate and combination | |
| -snes_ngmres_gammaC | - Residual tolerance for restart | |
| -snes_ngmres_epsilonB | - Difference tolerance between subsequent solutions triggering restart | |
| -snes_ngmres_deltaB | - Difference tolerance between residuals triggering restart | |
| -snes_ngmres_restart_fm_rise | - Restart on residual rise from x_M step | |
| -snes_ngmres_monitor | - Prints relevant information about the ngmres iteration | |
| -snes_linesearch_type <basic,l2,cp> | - Line search type used for the default smoother | |
| -additive_snes_linesearch_type | - linesearch type used to select between the candidate and combined solution with additive select type |
The N-GMRES method combines m previous solutions into a minimum-residual solution by solving a small linearized optimization problem at each iteration.
Very similar to the SNESANDERSON algorithm.
| 1. | - C. W. Oosterlee and T. Washio, "Krylov Subspace Acceleration of Nonlinear Multigrid with Application to Recirculating Flows", SIAM Journal on Scientific Computing, 21(5), 2000. | |
| 2. | - Peter R. Brune, Matthew G. Knepley, Barry F. Smith, and Xuemin Tu, "Composing Scalable Nonlinear Algebraic Solvers", SIAM Review, 57(4), 2015 |