1 2 #include <petsc-private/snesimpl.h> /*I "petscsnes.h" I*/ 3 #include <petscdmshell.h> 4 5 6 #undef __FUNCT__ 7 #define __FUNCT__ "SNESApplyPC" 8 /*@ 9 SNESApplyPC - Calls SNESSolve() on preconditioner for the SNES 10 11 Collective on SNES 12 13 Input Parameters: 14 + snes - the SNES context 15 - x - input vector 16 17 Output Parameter: 18 . y - function vector, as set by SNESSetFunction() 19 20 Notes: 21 SNESComputeFunction() should be called on X before SNESApplyPC() is called, as it is 22 with SNESComuteJacobian(). 23 24 Level: developer 25 26 .keywords: SNES, nonlinear, compute, function 27 28 .seealso: SNESGetPC(),SNESSetPC(),SNESComputeFunction() 29 @*/ 30 PetscErrorCode SNESApplyPC(SNES snes,Vec x,Vec f,PetscReal *fnorm,Vec y) 31 { 32 PetscErrorCode ierr; 33 34 PetscFunctionBegin; 35 PetscValidHeaderSpecific(snes,SNES_CLASSID,1); 36 PetscValidHeaderSpecific(x,VEC_CLASSID,2); 37 PetscValidHeaderSpecific(y,VEC_CLASSID,3); 38 PetscCheckSameComm(snes,1,x,2); 39 PetscCheckSameComm(snes,1,y,3); 40 ierr = VecValidValues(x,2,PETSC_TRUE);CHKERRQ(ierr); 41 if (snes->pc) { 42 if (f) { 43 ierr = SNESSetInitialFunction(snes->pc,f);CHKERRQ(ierr); 44 } 45 ierr = VecCopy(x,y);CHKERRQ(ierr); 46 ierr = PetscLogEventBegin(SNES_NPCSolve,snes->pc,x,y,0);CHKERRQ(ierr); 47 ierr = SNESSolve(snes->pc,snes->vec_rhs,y);CHKERRQ(ierr); 48 ierr = PetscLogEventEnd(SNES_NPCSolve,snes->pc,x,y,0);CHKERRQ(ierr); 49 ierr = VecAYPX(y,-1.0,x);CHKERRQ(ierr); 50 PetscFunctionReturn(0); 51 } 52 PetscFunctionReturn(0); 53 } 54 55 #undef __FUNCT__ 56 #define __FUNCT__ "SNESComputeFunctionDefaultPC" 57 PetscErrorCode SNESComputeFunctionDefaultPC(SNES snes,Vec X,Vec F) { 58 /* This is to be used as an argument to SNESMF -- NOT as a "function" */ 59 SNESConvergedReason reason; 60 PetscErrorCode ierr; 61 62 PetscFunctionBegin; 63 if (snes->pc) { 64 ierr = SNESApplyPC(snes,X,NULL,NULL,F);CHKERRQ(ierr); 65 ierr = SNESGetConvergedReason(snes->pc,&reason);CHKERRQ(ierr); 66 if (reason < 0 && reason != SNES_DIVERGED_MAX_IT) { 67 ierr = SNESSetFunctionDomainError(snes);CHKERRQ(ierr); 68 } 69 } else { 70 ierr = SNESComputeFunction(snes,X,F);CHKERRQ(ierr); 71 } 72 PetscFunctionReturn(0); 73 } 74 75 #undef __FUNCT__ 76 #define __FUNCT__ "SNESGetPCFunction" 77 /*@ 78 SNESGetPCFunction - Gets the function from a preconditioner after SNESSolve() has been called. 79 80 Collective on SNES 81 82 Input Parameters: 83 . snes - the SNES context 84 85 Output Parameter: 86 . F - function vector 87 . fnorm - the norm of F 88 89 Level: developer 90 91 .keywords: SNES, nonlinear, function 92 93 .seealso: SNESGetPC(),SNESSetPC(),SNESComputeFunction(),SNESApplyPC(),SNESSolve() 94 @*/ 95 PetscErrorCode SNESGetPCFunction(SNES snes,Vec F,PetscReal *fnorm) 96 { 97 PetscErrorCode ierr; 98 PCSide npcside; 99 SNESFunctionType functype; 100 SNESNormSchedule normschedule; 101 Vec FPC,XPC; 102 103 PetscFunctionBegin; 104 if (snes->pc) { 105 ierr = SNESGetPCSide(snes->pc,&npcside);CHKERRQ(ierr); 106 ierr = SNESGetFunctionType(snes->pc,&functype);CHKERRQ(ierr); 107 ierr = SNESGetNormSchedule(snes->pc,&normschedule);CHKERRQ(ierr); 108 109 /* check if the function is valid based upon how the inner solver is preconditioned */ 110 if (normschedule != SNES_NORM_NONE && normschedule != SNES_NORM_INITIAL_ONLY && (npcside == PC_RIGHT || functype == SNES_FUNCTION_UNPRECONDITIONED)) { 111 ierr = SNESGetFunction(snes->pc,&FPC,NULL,NULL);CHKERRQ(ierr); 112 if (FPC) { 113 if (fnorm) {ierr = SNESGetFunctionNorm(snes->pc,fnorm);CHKERRQ(ierr);} 114 ierr = VecCopy(FPC,F);CHKERRQ(ierr); 115 } else { 116 SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"Preconditioner has no function"); 117 } 118 } else { 119 ierr = SNESGetSolution(snes->pc,&XPC);CHKERRQ(ierr); 120 if (XPC) { 121 ierr = SNESComputeFunction(snes->pc,XPC,F);CHKERRQ(ierr); 122 if (fnorm) {ierr = VecNorm(F,NORM_2,fnorm);CHKERRQ(ierr);} 123 } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"Preconditioner has no solution"); 124 } 125 } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"No preconditioner set"); 126 PetscFunctionReturn(0); 127 } 128