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 Vec Y,X,F; 11 12 PetscFunctionBegin; 13 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); 14 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->numbermonitors) { 27 PetscReal fnorm; 28 ierr = VecNorm(F,NORM_2,&fnorm);CHKERRQ(ierr); 29 ierr = SNESMonitor(snes,0,fnorm);CHKERRQ(ierr); 30 } 31 32 /* Call general purpose update function */ 33 if (snes->ops->update) { 34 ierr = (*snes->ops->update)(snes, 0);CHKERRQ(ierr); 35 } 36 37 /* Solve J Y = F, where J is Jacobian matrix */ 38 ierr = SNESComputeJacobian(snes,X,snes->jacobian,snes->jacobian_pre);CHKERRQ(ierr); 39 ierr = KSPSetOperators(snes->ksp,snes->jacobian,snes->jacobian_pre);CHKERRQ(ierr); 40 ierr = KSPSolve(snes->ksp,F,Y);CHKERRQ(ierr); 41 snes->reason = SNES_CONVERGED_ITS; 42 SNESCheckKSPSolve(snes); 43 44 ierr = KSPGetIterationNumber(snes->ksp,&lits);CHKERRQ(ierr); 45 snes->linear_its += lits; 46 ierr = PetscInfo2(snes,"iter=%D, linear solve iterations=%D\n",snes->iter,lits);CHKERRQ(ierr); 47 snes->iter++; 48 49 /* Take the computed step. */ 50 ierr = VecAXPY(X,-1.0,Y);CHKERRQ(ierr); 51 if (snes->numbermonitors) { 52 PetscReal fnorm; 53 ierr = SNESComputeFunction(snes,X,F);CHKERRQ(ierr); 54 ierr = VecNorm(F,NORM_2,&fnorm);CHKERRQ(ierr); 55 ierr = SNESMonitor(snes,1,fnorm);CHKERRQ(ierr); 56 } 57 PetscFunctionReturn(0); 58 } 59 60 #undef __FUNCT__ 61 #define __FUNCT__ "SNESSetUp_KSPONLY" 62 static PetscErrorCode SNESSetUp_KSPONLY(SNES snes) 63 { 64 PetscErrorCode ierr; 65 66 PetscFunctionBegin; 67 ierr = SNESSetUpMatrices(snes);CHKERRQ(ierr); 68 PetscFunctionReturn(0); 69 } 70 71 #undef __FUNCT__ 72 #define __FUNCT__ "SNESDestroy_KSPONLY" 73 static PetscErrorCode SNESDestroy_KSPONLY(SNES snes) 74 { 75 76 PetscFunctionBegin; 77 PetscFunctionReturn(0); 78 } 79 80 /* -------------------------------------------------------------------------- */ 81 /*MC 82 SNESKSPONLY - Nonlinear solver that only performs one Newton step and does not compute any norms. 83 The main purpose of this solver is to solve linear problems using the SNES interface, without 84 any additional overhead in the form of vector operations. 85 86 Level: beginner 87 88 .seealso: SNESCreate(), SNES, SNESSetType(), SNESNEWTONLS, SNESNEWTONTR 89 M*/ 90 #undef __FUNCT__ 91 #define __FUNCT__ "SNESCreate_KSPONLY" 92 PETSC_EXTERN PetscErrorCode SNESCreate_KSPONLY(SNES snes) 93 { 94 95 PetscFunctionBegin; 96 snes->ops->setup = SNESSetUp_KSPONLY; 97 snes->ops->solve = SNESSolve_KSPONLY; 98 snes->ops->destroy = SNESDestroy_KSPONLY; 99 snes->ops->setfromoptions = 0; 100 snes->ops->view = 0; 101 snes->ops->reset = 0; 102 103 snes->usesksp = PETSC_TRUE; 104 snes->usespc = PETSC_FALSE; 105 106 snes->alwayscomputesfinalresidual = PETSC_FALSE; 107 108 snes->data = 0; 109 PetscFunctionReturn(0); 110 } 111