1 #define PETSCKSP_DLL 2 3 /* 4 Full multigrid using either additive or multiplicative V or W cycle 5 */ 6 #include "src/ksp/pc/impls/mg/mgimpl.h" 7 8 EXTERN PetscErrorCode MGMCycle_Private(MG *,PetscTruth*); 9 10 /* 11 MGFCycle_Private - Given an MG structure created with MGCreate() runs 12 full multigrid. 13 14 Iput Parameters: 15 . mg - structure created with MGCreate(). 16 17 Note: This may not be what others call full multigrid. What we 18 do is restrict the rhs to all levels, then starting 19 on the coarsest level work our way up generating 20 initial guess for the next level. This provides an 21 improved preconditioner but not a great improvement. 22 */ 23 #undef __FUNCT__ 24 #define __FUNCT__ "MGFCycle_Private" 25 PetscErrorCode MGFCycle_Private(MG *mg) 26 { 27 PetscErrorCode ierr; 28 PetscInt i,l = mg[0]->levels; 29 PetscScalar zero = 0.0; 30 31 PetscFunctionBegin; 32 /* restrict the RHS through all levels to coarsest. */ 33 for (i=l-1; i>0; i--){ 34 ierr = MatRestrict(mg[i]->restrct,mg[i]->b,mg[i-1]->b);CHKERRQ(ierr); 35 } 36 37 /* work our way up through the levels */ 38 ierr = VecSet(&zero,mg[0]->x);CHKERRQ(ierr); 39 for (i=0; i<l-1; i++) { 40 ierr = MGMCycle_Private(&mg[i],PETSC_NULL);CHKERRQ(ierr); 41 ierr = MatInterpolate(mg[i+1]->interpolate,mg[i]->x,mg[i+1]->x);CHKERRQ(ierr); 42 } 43 ierr = MGMCycle_Private(&mg[l-1],PETSC_NULL);CHKERRQ(ierr); 44 PetscFunctionReturn(0); 45 } 46 47 /* 48 MGKCycle_Private - Given an MG structure created with MGCreate() runs 49 full Kascade MG solve. 50 51 Iput Parameters: 52 . mg - structure created with MGCreate(). 53 54 Note: This may not be what others call Kascadic MG. 55 */ 56 #undef __FUNCT__ 57 #define __FUNCT__ "MGKCycle_Private" 58 PetscErrorCode MGKCycle_Private(MG *mg) 59 { 60 PetscErrorCode ierr; 61 PetscInt i,l = mg[0]->levels; 62 PetscScalar zero = 0.0; 63 64 PetscFunctionBegin; 65 /* restrict the RHS through all levels to coarsest. */ 66 for (i=l-1; i>0; i--){ 67 ierr = MatRestrict(mg[i]->restrct,mg[i]->b,mg[i-1]->b);CHKERRQ(ierr); 68 } 69 70 /* work our way up through the levels */ 71 ierr = VecSet(&zero,mg[0]->x);CHKERRQ(ierr); 72 for (i=0; i<l-1; i++) { 73 if (mg[i]->eventsolve) {ierr = PetscLogEventBegin(mg[i]->eventsolve,0,0,0,0);CHKERRQ(ierr);} 74 ierr = KSPSolve(mg[i]->smoothd,mg[i]->b,mg[i]->x);CHKERRQ(ierr); 75 if (mg[i]->eventsolve) {ierr = PetscLogEventEnd(mg[i]->eventsolve,0,0,0,0);CHKERRQ(ierr);} 76 ierr = MatInterpolate(mg[i+1]->interpolate,mg[i]->x,mg[i+1]->x);CHKERRQ(ierr); 77 } 78 if (mg[l-1]->eventsolve) {ierr = PetscLogEventBegin(mg[l-1]->eventsolve,0,0,0,0);CHKERRQ(ierr);} 79 ierr = KSPSolve(mg[l-1]->smoothd,mg[l-1]->b,mg[l-1]->x);CHKERRQ(ierr); 80 if (mg[l-1]->eventsolve) {ierr = PetscLogEventEnd(mg[l-1]->eventsolve,0,0,0,0);CHKERRQ(ierr);} 81 82 PetscFunctionReturn(0); 83 } 84 85 86