1 2 #include <petsc/private/snesimpl.h> 3 4 static PetscErrorCode SNESSolve_KSPONLY(SNES snes) 5 { 6 PetscErrorCode ierr; 7 PetscInt lits; 8 Vec Y,X,F; 9 10 PetscFunctionBegin; 11 if (snes->xl || snes->xu || snes->ops->computevariablebounds) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_WRONGSTATE, "SNES solver %s does not support bounds", ((PetscObject)snes)->type_name); 12 13 snes->numFailures = 0; 14 snes->numLinearSolveFailures = 0; 15 snes->reason = SNES_CONVERGED_ITERATING; 16 snes->iter = 0; 17 snes->norm = 0.0; 18 19 X = snes->vec_sol; 20 F = snes->vec_func; 21 Y = snes->vec_sol_update; 22 23 ierr = SNESComputeFunction(snes,X,F);CHKERRQ(ierr); 24 if (snes->numbermonitors) { 25 PetscReal fnorm; 26 ierr = VecNorm(F,NORM_2,&fnorm);CHKERRQ(ierr); 27 ierr = SNESMonitor(snes,0,fnorm);CHKERRQ(ierr); 28 } 29 30 /* Call general purpose update function */ 31 if (snes->ops->update) { 32 ierr = (*snes->ops->update)(snes, 0);CHKERRQ(ierr); 33 } 34 35 /* Solve J Y = F, where J is Jacobian matrix */ 36 ierr = SNESComputeJacobian(snes,X,snes->jacobian,snes->jacobian_pre);CHKERRQ(ierr); 37 ierr = KSPSetOperators(snes->ksp,snes->jacobian,snes->jacobian_pre);CHKERRQ(ierr); 38 ierr = KSPSolve(snes->ksp,F,Y);CHKERRQ(ierr); 39 snes->reason = SNES_CONVERGED_ITS; 40 SNESCheckKSPSolve(snes); 41 42 ierr = KSPGetIterationNumber(snes->ksp,&lits);CHKERRQ(ierr); 43 snes->linear_its += lits; 44 ierr = PetscInfo2(snes,"iter=%D, linear solve iterations=%D\n",snes->iter,lits);CHKERRQ(ierr); 45 snes->iter++; 46 47 /* Take the computed step. */ 48 ierr = VecAXPY(X,-1.0,Y);CHKERRQ(ierr); 49 if (snes->numbermonitors) { 50 PetscReal fnorm; 51 ierr = SNESComputeFunction(snes,X,F);CHKERRQ(ierr); 52 ierr = VecNorm(F,NORM_2,&fnorm);CHKERRQ(ierr); 53 ierr = SNESMonitor(snes,1,fnorm);CHKERRQ(ierr); 54 } 55 PetscFunctionReturn(0); 56 } 57 58 static PetscErrorCode SNESSetUp_KSPONLY(SNES snes) 59 { 60 PetscErrorCode ierr; 61 62 PetscFunctionBegin; 63 ierr = SNESSetUpMatrices(snes);CHKERRQ(ierr); 64 PetscFunctionReturn(0); 65 } 66 67 static PetscErrorCode SNESDestroy_KSPONLY(SNES snes) 68 { 69 70 PetscFunctionBegin; 71 PetscFunctionReturn(0); 72 } 73 74 /* -------------------------------------------------------------------------- */ 75 /*MC 76 SNESKSPONLY - Nonlinear solver that only performs one Newton step and does not compute any norms. 77 The main purpose of this solver is to solve linear problems using the SNES interface, without 78 any additional overhead in the form of vector operations. 79 80 Level: beginner 81 82 .seealso: SNESCreate(), SNES, SNESSetType(), SNESNEWTONLS, SNESNEWTONTR 83 M*/ 84 PETSC_EXTERN PetscErrorCode SNESCreate_KSPONLY(SNES snes) 85 { 86 87 PetscFunctionBegin; 88 snes->ops->setup = SNESSetUp_KSPONLY; 89 snes->ops->solve = SNESSolve_KSPONLY; 90 snes->ops->destroy = SNESDestroy_KSPONLY; 91 snes->ops->setfromoptions = 0; 92 snes->ops->view = 0; 93 snes->ops->reset = 0; 94 95 snes->usesksp = PETSC_TRUE; 96 snes->usesnpc = PETSC_FALSE; 97 98 snes->alwayscomputesfinalresidual = PETSC_FALSE; 99 100 snes->data = 0; 101 PetscFunctionReturn(0); 102 } 103