1 2 #include <petsc-private/snesimpl.h> 3 4 #undef __FUNCT__ 5 #define __FUNCT__ "SNESSolve_KSPONLY" 6 static PetscErrorCode SNESSolve_KSPONLY(SNES snes) 7 { 8 PetscErrorCode ierr; 9 PetscInt lits; 10 MatStructure flg = DIFFERENT_NONZERO_PATTERN; 11 Vec Y,X,F; 12 KSPConvergedReason kspreason; 13 14 PetscFunctionBegin; 15 snes->numFailures = 0; 16 snes->numLinearSolveFailures = 0; 17 snes->reason = SNES_CONVERGED_ITERATING; 18 snes->iter = 0; 19 snes->norm = 0.0; 20 21 X = snes->vec_sol; 22 F = snes->vec_func; 23 Y = snes->vec_sol_update; 24 25 ierr = SNESComputeFunction(snes,X,F);CHKERRQ(ierr); 26 if (snes->domainerror) { 27 snes->reason = SNES_DIVERGED_FUNCTION_DOMAIN; 28 PetscFunctionReturn(0); 29 } 30 if (snes->numbermonitors) { 31 PetscReal fnorm; 32 ierr = VecNorm(F,NORM_2,&fnorm);CHKERRQ(ierr); 33 ierr = SNESMonitor(snes,0,fnorm);CHKERRQ(ierr); 34 } 35 36 /* Call general purpose update function */ 37 if (snes->ops->update) { 38 ierr = (*snes->ops->update)(snes, 0);CHKERRQ(ierr); 39 } 40 41 /* Solve J Y = F, where J is Jacobian matrix */ 42 ierr = SNESComputeJacobian(snes,X,&snes->jacobian,&snes->jacobian_pre,&flg);CHKERRQ(ierr); 43 ierr = KSPSetOperators(snes->ksp,snes->jacobian,snes->jacobian_pre,flg);CHKERRQ(ierr); 44 ierr = KSPSolve(snes->ksp,F,Y);CHKERRQ(ierr); 45 ierr = KSPGetConvergedReason(snes->ksp,&kspreason);CHKERRQ(ierr); 46 if (kspreason < 0 && ++snes->numLinearSolveFailures >= snes->maxLinearSolveFailures) { 47 ierr = PetscInfo2(snes,"iter=%D, number linear solve failures %D greater than current SNES allowed, stopping solve\n",snes->iter,snes->numLinearSolveFailures);CHKERRQ(ierr); 48 snes->reason = SNES_DIVERGED_LINEAR_SOLVE; 49 } else snes->reason = SNES_CONVERGED_ITS; 50 51 ierr = KSPGetIterationNumber(snes->ksp,&lits);CHKERRQ(ierr); 52 snes->linear_its += lits; 53 ierr = PetscInfo2(snes,"iter=%D, linear solve iterations=%D\n",snes->iter,lits);CHKERRQ(ierr); 54 snes->iter++; 55 56 /* Take the computed step. */ 57 ierr = VecAXPY(X,-1.0,Y);CHKERRQ(ierr); 58 if (snes->numbermonitors) { 59 PetscReal fnorm; 60 ierr = SNESComputeFunction(snes,X,F);CHKERRQ(ierr); 61 ierr = VecNorm(F,NORM_2,&fnorm);CHKERRQ(ierr); 62 ierr = SNESMonitor(snes,1,fnorm);CHKERRQ(ierr); 63 } 64 PetscFunctionReturn(0); 65 } 66 67 #undef __FUNCT__ 68 #define __FUNCT__ "SNESSetUp_KSPONLY" 69 static PetscErrorCode SNESSetUp_KSPONLY(SNES snes) 70 { 71 PetscErrorCode ierr; 72 73 PetscFunctionBegin; 74 ierr = SNESSetUpMatrices(snes);CHKERRQ(ierr); 75 PetscFunctionReturn(0); 76 } 77 78 #undef __FUNCT__ 79 #define __FUNCT__ "SNESDestroy_KSPONLY" 80 static PetscErrorCode SNESDestroy_KSPONLY(SNES snes) 81 { 82 83 PetscFunctionBegin; 84 PetscFunctionReturn(0); 85 } 86 87 /* -------------------------------------------------------------------------- */ 88 /*MC 89 SNESKSPONLY - Nonlinear solver that only performs one Newton step and does not compute any norms. 90 The main purpose of this solver is to solve linear problems using the SNES interface, without 91 any additional overhead in the form of vector operations. 92 93 Level: beginner 94 95 .seealso: SNESCreate(), SNES, SNESSetType(), SNESNEWTONLS, SNESNEWTONTR 96 M*/ 97 #undef __FUNCT__ 98 #define __FUNCT__ "SNESCreate_KSPONLY" 99 PETSC_EXTERN PetscErrorCode SNESCreate_KSPONLY(SNES snes) 100 { 101 102 PetscFunctionBegin; 103 snes->ops->setup = SNESSetUp_KSPONLY; 104 snes->ops->solve = SNESSolve_KSPONLY; 105 snes->ops->destroy = SNESDestroy_KSPONLY; 106 snes->ops->setfromoptions = 0; 107 snes->ops->view = 0; 108 snes->ops->reset = 0; 109 110 snes->usesksp = PETSC_TRUE; 111 snes->usespc = PETSC_FALSE; 112 113 snes->data = 0; 114 PetscFunctionReturn(0); 115 } 116