1 #include <petsc/private/snesimpl.h> /*I "petscsnes.h" I*/ 2 3 typedef struct { 4 PetscBool transpose_solve; 5 } SNES_KSPONLY; 6 7 static PetscErrorCode SNESSolve_KSPONLY(SNES snes) 8 { 9 SNES_KSPONLY *ksponly = (SNES_KSPONLY *)snes->data; 10 PetscInt lits; 11 Vec Y, X, F; 12 SNESNormSchedule normschedule; 13 14 PetscFunctionBegin; 15 PetscCheck(!snes->xl && !snes->xu && !snes->ops->computevariablebounds, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_WRONGSTATE, "SNES solver %s does not support bounds", ((PetscObject)snes)->type_name); 16 17 snes->numFailures = 0; 18 snes->numLinearSolveFailures = 0; 19 snes->reason = SNES_CONVERGED_ITERATING; 20 snes->iter = 0; 21 snes->norm = 0.0; 22 23 X = snes->vec_sol; 24 F = snes->vec_func; 25 Y = snes->vec_sol_update; 26 27 if (!snes->vec_func_init_set) PetscCall(SNESComputeFunction(snes, X, F)); 28 else snes->vec_func_init_set = PETSC_FALSE; 29 30 PetscCall(SNESGetNormSchedule(snes, &normschedule)); 31 if (snes->numbermonitors && (normschedule == SNES_NORM_ALWAYS || normschedule == SNES_NORM_INITIAL_ONLY || normschedule == SNES_NORM_INITIAL_FINAL_ONLY)) { 32 PetscReal fnorm; 33 PetscCall(VecNorm(F, NORM_2, &fnorm)); 34 SNESCheckFunctionNorm(snes, fnorm); 35 PetscCall(SNESMonitor(snes, 0, fnorm)); 36 } 37 38 /* Call general purpose update function */ 39 PetscTryTypeMethod(snes, update, 0); 40 41 /* Solve J Y = F, where J is Jacobian matrix */ 42 PetscCall(SNESComputeJacobian(snes, X, snes->jacobian, snes->jacobian_pre)); 43 44 SNESCheckJacobianDomainerror(snes); 45 46 PetscCall(KSPSetOperators(snes->ksp, snes->jacobian, snes->jacobian_pre)); 47 if (ksponly->transpose_solve) { 48 PetscCall(KSPSolveTranspose(snes->ksp, F, Y)); 49 } else { 50 PetscCall(KSPSolve(snes->ksp, F, Y)); 51 } 52 snes->reason = SNES_CONVERGED_ITS; 53 SNESCheckKSPSolve(snes); 54 55 PetscCall(KSPGetIterationNumber(snes->ksp, &lits)); 56 PetscCall(PetscInfo(snes, "iter=%" PetscInt_FMT ", linear solve iterations=%" PetscInt_FMT "\n", snes->iter, lits)); 57 snes->iter++; 58 59 /* Take the computed step. */ 60 PetscCall(VecAXPY(X, -1.0, Y)); 61 62 if (snes->numbermonitors && (normschedule == SNES_NORM_ALWAYS || normschedule == SNES_NORM_FINAL_ONLY || normschedule == SNES_NORM_INITIAL_FINAL_ONLY)) { 63 PetscReal fnorm; 64 PetscCall(SNESComputeFunction(snes, X, F)); 65 PetscCall(VecNorm(F, NORM_2, &fnorm)); 66 SNESCheckFunctionNorm(snes, fnorm); 67 PetscCall(SNESMonitor(snes, 1, fnorm)); 68 } 69 PetscFunctionReturn(PETSC_SUCCESS); 70 } 71 72 static PetscErrorCode SNESSetUp_KSPONLY(SNES snes) 73 { 74 PetscFunctionBegin; 75 PetscCall(SNESSetUpMatrices(snes)); 76 PetscFunctionReturn(PETSC_SUCCESS); 77 } 78 79 static PetscErrorCode SNESDestroy_KSPONLY(SNES snes) 80 { 81 PetscFunctionBegin; 82 PetscCall(PetscFree(snes->data)); 83 PetscFunctionReturn(PETSC_SUCCESS); 84 } 85 86 /*MC 87 SNESKSPONLY - Nonlinear solver that performs one Newton step with `KSPSolve()` and does not compute any norms. 88 89 Level: beginner 90 91 Note: 92 The main purpose of this solver is to solve linear problems using the `SNES` interface, without 93 any additional overhead in the form of vector norm operations. 94 95 .seealso: [](ch_snes), `SNES`, `SNESType`, `SNESCreate()`, `SNES`, `SNESSetType()`, `SNESNEWTONLS`, `SNESNEWTONTR`, `SNESKSPTRANSPOSEONLY` 96 M*/ 97 PETSC_EXTERN PetscErrorCode SNESCreate_KSPONLY(SNES snes) 98 { 99 SNES_KSPONLY *ksponly; 100 101 PetscFunctionBegin; 102 snes->ops->setup = SNESSetUp_KSPONLY; 103 snes->ops->solve = SNESSolve_KSPONLY; 104 snes->ops->destroy = SNESDestroy_KSPONLY; 105 snes->ops->setfromoptions = NULL; 106 snes->ops->view = NULL; 107 snes->ops->reset = NULL; 108 109 snes->usesksp = PETSC_TRUE; 110 snes->usesnpc = PETSC_FALSE; 111 112 snes->alwayscomputesfinalresidual = PETSC_FALSE; 113 114 PetscCall(SNESParametersInitialize(snes)); 115 116 PetscCall(PetscNew(&ksponly)); 117 snes->data = (void *)ksponly; 118 PetscFunctionReturn(PETSC_SUCCESS); 119 } 120 121 /*MC 122 SNESKSPTRANSPOSEONLY - Nonlinear solver that performs one Newton step with `KSPSolveTranspose()` and does not compute any norms. 123 124 Level: beginner 125 126 Note: 127 The main purpose of this solver is to solve transposed linear problems using the `SNES` interface, without 128 any additional overhead in the form of vector operations within adjoint solvers. 129 130 .seealso: [](ch_snes), `SNES`, `SNESType`, `SNESCreate()`, `SNES`, `SNESSetType()`, `SNESKS`, `SNESNEWTONLS`, `SNESNEWTONTR` 131 M*/ 132 PETSC_EXTERN PetscErrorCode SNESCreate_KSPTRANSPOSEONLY(SNES snes) 133 { 134 SNES_KSPONLY *kspo; 135 136 PetscFunctionBegin; 137 PetscCall(SNESCreate_KSPONLY(snes)); 138 PetscCall(PetscObjectChangeTypeName((PetscObject)snes, SNESKSPTRANSPOSEONLY)); 139 kspo = (SNES_KSPONLY *)snes->data; 140 kspo->transpose_solve = PETSC_TRUE; 141 PetscFunctionReturn(PETSC_SUCCESS); 142 } 143