| -snes_trtol <tol> | - trust region tolerance | |
| -snes_tr_mu <mu> | - trust region parameter | |
| -snes_tr_eta <eta> | - trust region parameter | |
| -snes_tr_sigma <sigma> | - trust region parameter | |
| -snes_tr_delta0 <delta0> | - initial size of the trust region is delta0*norm2(x) | |
| -snes_tr_delta1 <delta1> | - trust region parameter | |
| -snes_tr_delta2 <delta2> | - trust region parameter | |
| -snes_tr_delta3 <delta3> | - trust region parameter |
The basic algorithm is taken from "The Minpack Project", by More', Sorensen, Garbow, Hillstrom, pages 88-111 of "Sources and Development of Mathematical Software", Wayne Cowell, editor.