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 14 if (snes->xl || snes->xu || snes->ops->computevariablebounds) { 15 SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_WRONGSTATE, "SNES solver %s does not support bounds", ((PetscObject)snes)->type_name); 16 } 17 18 snes->numFailures = 0; 19 snes->numLinearSolveFailures = 0; 20 snes->reason = SNES_CONVERGED_ITERATING; 21 snes->iter = 0; 22 snes->norm = 0.0; 23 24 X = snes->vec_sol; 25 F = snes->vec_func; 26 Y = snes->vec_sol_update; 27 28 ierr = SNESComputeFunction(snes,X,F);CHKERRQ(ierr); 29 if (snes->numbermonitors) { 30 PetscReal fnorm; 31 ierr = VecNorm(F,NORM_2,&fnorm);CHKERRQ(ierr); 32 ierr = SNESMonitor(snes,0,fnorm);CHKERRQ(ierr); 33 } 34 35 /* Call general purpose update function */ 36 if (snes->ops->update) { 37 ierr = (*snes->ops->update)(snes, 0);CHKERRQ(ierr); 38 } 39 40 /* Solve J Y = F, where J is Jacobian matrix */ 41 ierr = SNESComputeJacobian(snes,X,snes->jacobian,snes->jacobian_pre);CHKERRQ(ierr); 42 ierr = KSPSetOperators(snes->ksp,snes->jacobian,snes->jacobian_pre);CHKERRQ(ierr); 43 ierr = KSPSolve(snes->ksp,F,Y);CHKERRQ(ierr); 44 snes->reason = SNES_CONVERGED_ITS; 45 SNESCheckKSPSolve(snes); 46 47 ierr = KSPGetIterationNumber(snes->ksp,&lits);CHKERRQ(ierr); 48 snes->linear_its += lits; 49 ierr = PetscInfo2(snes,"iter=%D, linear solve iterations=%D\n",snes->iter,lits);CHKERRQ(ierr); 50 snes->iter++; 51 52 /* Take the computed step. */ 53 ierr = VecAXPY(X,-1.0,Y);CHKERRQ(ierr); 54 if (snes->numbermonitors) { 55 PetscReal fnorm; 56 ierr = SNESComputeFunction(snes,X,F);CHKERRQ(ierr); 57 ierr = VecNorm(F,NORM_2,&fnorm);CHKERRQ(ierr); 58 ierr = SNESMonitor(snes,1,fnorm);CHKERRQ(ierr); 59 } 60 PetscFunctionReturn(0); 61 } 62 63 #undef __FUNCT__ 64 #define __FUNCT__ "SNESSetUp_KSPONLY" 65 static PetscErrorCode SNESSetUp_KSPONLY(SNES snes) 66 { 67 PetscErrorCode ierr; 68 69 PetscFunctionBegin; 70 ierr = SNESSetUpMatrices(snes);CHKERRQ(ierr); 71 PetscFunctionReturn(0); 72 } 73 74 #undef __FUNCT__ 75 #define __FUNCT__ "SNESDestroy_KSPONLY" 76 static PetscErrorCode SNESDestroy_KSPONLY(SNES snes) 77 { 78 79 PetscFunctionBegin; 80 PetscFunctionReturn(0); 81 } 82 83 /* -------------------------------------------------------------------------- */ 84 /*MC 85 SNESKSPONLY - Nonlinear solver that only performs one Newton step and does not compute any norms. 86 The main purpose of this solver is to solve linear problems using the SNES interface, without 87 any additional overhead in the form of vector operations. 88 89 Level: beginner 90 91 .seealso: SNESCreate(), SNES, SNESSetType(), SNESNEWTONLS, SNESNEWTONTR 92 M*/ 93 #undef __FUNCT__ 94 #define __FUNCT__ "SNESCreate_KSPONLY" 95 PETSC_EXTERN PetscErrorCode SNESCreate_KSPONLY(SNES snes) 96 { 97 98 PetscFunctionBegin; 99 snes->ops->setup = SNESSetUp_KSPONLY; 100 snes->ops->solve = SNESSolve_KSPONLY; 101 snes->ops->destroy = SNESDestroy_KSPONLY; 102 snes->ops->setfromoptions = 0; 103 snes->ops->view = 0; 104 snes->ops->reset = 0; 105 106 snes->usesksp = PETSC_TRUE; 107 snes->usespc = PETSC_FALSE; 108 109 snes->data = 0; 110 PetscFunctionReturn(0); 111 } 112