1 #include <private/snesimpl.h> /*I "petscsnes.h" I*/ 2 3 typedef struct { 4 PetscInt sweeps; 5 } SNES_GS; 6 7 #undef __FUNCT__ 8 #define __FUNCT__ "SNESReset_GS" 9 PetscErrorCode SNESReset_GS(SNES snes) 10 { 11 PetscFunctionBegin; 12 PetscFunctionReturn(0); 13 } 14 15 #undef __FUNCT__ 16 #define __FUNCT__ "SNESDestroy_GS" 17 PetscErrorCode SNESDestroy_GS(SNES snes) 18 { 19 PetscErrorCode ierr; 20 21 PetscFunctionBegin; 22 ierr = SNESReset_GS(snes);CHKERRQ(ierr); 23 ierr = PetscFree(snes->data); 24 PetscFunctionReturn(0); 25 } 26 27 #undef __FUNCT__ 28 #define __FUNCT__ "SNESSetUp_GS" 29 PetscErrorCode SNESSetUp_GS(SNES snes) 30 { 31 PetscFunctionBegin; 32 PetscFunctionReturn(0); 33 } 34 35 #undef __FUNCT__ 36 #define __FUNCT__ "SNESSetFromOptions_GS" 37 PetscErrorCode SNESSetFromOptions_GS(SNES snes) 38 { 39 PetscErrorCode ierr; 40 41 PetscFunctionBegin; 42 ierr = PetscOptionsHead("SNES GS options");CHKERRQ(ierr); 43 PetscFunctionReturn(0); 44 } 45 46 #undef __FUNCT__ 47 #define __FUNCT__ "SNESView_GS" 48 PetscErrorCode SNESView_GS(SNES snes, PetscViewer viewer) 49 { 50 PetscFunctionBegin; 51 PetscFunctionReturn(0); 52 } 53 54 #undef __FUNCT__ 55 #define __FUNCT__ "SNESSolve_GS" 56 PetscErrorCode SNESSolve_GS(SNES snes) 57 { 58 Vec F; 59 Vec X; 60 Vec B; 61 PetscInt i; 62 PetscReal fnorm; 63 PetscErrorCode ierr; 64 65 PetscFunctionBegin; 66 67 X = snes->vec_sol; 68 F = snes->vec_func; 69 B = snes->vec_rhs; 70 71 ierr = PetscObjectTakeAccess(snes);CHKERRQ(ierr); 72 snes->iter = 0; 73 snes->norm = 0.; 74 ierr = PetscObjectGrantAccess(snes);CHKERRQ(ierr); 75 76 snes->reason = SNES_CONVERGED_ITERATING; 77 /* compute the initial function and preconditioned update delX */ 78 ierr = SNESComputeFunction(snes,X,F);CHKERRQ(ierr); 79 if (snes->domainerror) { 80 snes->reason = SNES_DIVERGED_FUNCTION_DOMAIN; 81 PetscFunctionReturn(0); 82 } 83 /* convergence test */ 84 ierr = VecNorm(F, NORM_2, &fnorm);CHKERRQ(ierr); /* fnorm <- ||F|| */ 85 if (PetscIsInfOrNanReal(fnorm)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_FP,"Infinite or not-a-number generated in norm"); 86 ierr = PetscObjectTakeAccess(snes);CHKERRQ(ierr); 87 snes->norm = fnorm; 88 ierr = PetscObjectGrantAccess(snes);CHKERRQ(ierr); 89 SNESLogConvHistory(snes,fnorm,0); 90 ierr = SNESMonitor(snes,0,fnorm);CHKERRQ(ierr); 91 92 /* set parameter for default relative tolerance convergence test */ 93 snes->ttol = fnorm*snes->rtol; 94 /* test convergence */ 95 ierr = (*snes->ops->converged)(snes,0,0.0,0.0,fnorm,&snes->reason,snes->cnvP);CHKERRQ(ierr); 96 if (snes->reason) PetscFunctionReturn(0); 97 98 /* Call general purpose update function */ 99 if (snes->ops->update) { 100 ierr = (*snes->ops->update)(snes, snes->iter);CHKERRQ(ierr); 101 } 102 for (i = 0; i < snes->max_its; i++) { 103 ierr = SNESComputeGS(snes, B, X);CHKERRQ(ierr); 104 ierr = SNESComputeFunction(snes,X,F);CHKERRQ(ierr); 105 if (snes->domainerror) { 106 snes->reason = SNES_DIVERGED_FUNCTION_DOMAIN; 107 PetscFunctionReturn(0); 108 } 109 ierr = VecNorm(F, NORM_2, &fnorm);CHKERRQ(ierr); /* fnorm <- ||F|| */ 110 if (PetscIsInfOrNanReal(fnorm)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_FP,"Infinite or not-a-number generated in norm"); 111 /* Monitor convergence */ 112 ierr = PetscObjectTakeAccess(snes);CHKERRQ(ierr); 113 snes->iter = i+1; 114 snes->norm = fnorm; 115 ierr = PetscObjectGrantAccess(snes);CHKERRQ(ierr); 116 SNESLogConvHistory(snes,snes->norm,0); 117 ierr = SNESMonitor(snes,snes->iter,snes->norm);CHKERRQ(ierr); 118 119 /* Test for convergence */ 120 ierr = (*snes->ops->converged)(snes,snes->iter,0.0,0.0,fnorm,&snes->reason,snes->cnvP);CHKERRQ(ierr); 121 if (snes->reason) PetscFunctionReturn(0); 122 123 /* Call general purpose update function */ 124 if (snes->ops->update) { 125 ierr = (*snes->ops->update)(snes, snes->iter);CHKERRQ(ierr); 126 } 127 } 128 if (!snes->reason) snes->reason = SNES_CONVERGED_ITS; /* GS is meant to be used as a preconditioner */ 129 PetscFunctionReturn(0); 130 } 131 132 /*MC 133 SNESGS - Just calls the user-provided solution routine provided with SNESSetGS() 134 135 Level: advanced 136 137 Notes: 138 the Gauss-Seidel smoother is inherited through composition. If a solver has been created with SNESGetPC(), it will have 139 its parent's Gauss-Seidel routine associated with it. 140 141 .seealso: SNESCreate(), SNES, SNESSetType(), SNESSetGS(), SNESType (for list of available types) 142 M*/ 143 144 EXTERN_C_BEGIN 145 #undef __FUNCT__ 146 #define __FUNCT__ "SNESCreate_GS" 147 PetscErrorCode SNESCreate_GS(SNES snes) 148 { 149 SNES_GS *gs; 150 PetscErrorCode ierr; 151 152 PetscFunctionBegin; 153 snes->ops->destroy = SNESDestroy_GS; 154 snes->ops->setup = SNESSetUp_GS; 155 snes->ops->setfromoptions = SNESSetFromOptions_GS; 156 snes->ops->view = SNESView_GS; 157 snes->ops->solve = SNESSolve_GS; 158 snes->ops->reset = SNESReset_GS; 159 160 snes->usesksp = PETSC_FALSE; 161 snes->usespc = PETSC_FALSE; 162 163 ierr = PetscNewLog(snes, SNES_GS, &gs);CHKERRQ(ierr); 164 snes->data = (void*) gs; 165 PetscFunctionReturn(0); 166 } 167 EXTERN_C_END 168