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 EXTERN_C_BEGIN 98 #undef __FUNCT__ 99 #define __FUNCT__ "SNESCreate_KSPONLY" 100 PetscErrorCode SNESCreate_KSPONLY(SNES snes) 101 { 102 103 PetscFunctionBegin; 104 snes->ops->setup = SNESSetUp_KSPONLY; 105 snes->ops->solve = SNESSolve_KSPONLY; 106 snes->ops->destroy = SNESDestroy_KSPONLY; 107 snes->ops->setfromoptions = 0; 108 snes->ops->view = 0; 109 snes->ops->reset = 0; 110 111 snes->usesksp = PETSC_TRUE; 112 snes->usespc = PETSC_FALSE; 113 114 snes->data = 0; 115 PetscFunctionReturn(0); 116 } 117 EXTERN_C_END 118