1 #include <../src/snes/impls/fas/fasimpls.h> /*I "petscsnes.h" I*/ 2 3 /*@ 4 SNESFASGetGalerkin - Gets if the coarse problems are formed by projection to the fine problem 5 6 Not collective but the result would be the same on all MPI ranks 7 8 Input Parameter: 9 . snes - the `SNESFAS` nonlinear solver context 10 11 Output parameter: 12 . flg - `PETSC_TRUE` if the coarse problem is formed by projection 13 14 Level: advanced 15 16 .seealso: `SNESFAS`, `SNESFASSetLevels()`, `SNESFASSetGalerkin()` 17 @*/ 18 PetscErrorCode SNESFASGetGalerkin(SNES snes, PetscBool *flg) 19 { 20 SNES_FAS *fas; 21 22 PetscFunctionBegin; 23 PetscValidHeaderSpecificType(snes, SNES_CLASSID, 1, SNESFAS); 24 fas = (SNES_FAS *)snes->data; 25 *flg = fas->galerkin; 26 PetscFunctionReturn(0); 27 } 28 29 /*@ 30 SNESFASSetGalerkin - Sets coarse problems as formed by projection to the fine problem 31 32 Collective 33 34 Input Parameters: 35 + snes - the `SNESFAS` nonlinear solver context 36 - flg - `PETSC_TRUE` to use the projection process 37 38 Level: advanced 39 40 .seealso: `SNESFAS`, `SNESFASSetLevels()`, `SNESFASGetGalerkin()` 41 @*/ 42 PetscErrorCode SNESFASSetGalerkin(SNES snes, PetscBool flg) 43 { 44 SNES_FAS *fas; 45 46 PetscFunctionBegin; 47 PetscValidHeaderSpecificType(snes, SNES_CLASSID, 1, SNESFAS); 48 fas = (SNES_FAS *)snes->data; 49 fas->galerkin = flg; 50 if (fas->next) PetscCall(SNESFASSetGalerkin(fas->next, flg)); 51 PetscFunctionReturn(0); 52 } 53 54 /*@C 55 SNESFASGalerkinFunctionDefault - Computes the Galerkin FAS function 56 57 Collective 58 59 Input Parameters: 60 + snes - the `SNESFAS` nonlinear solver context 61 . X - input vector 62 - ctx - the application context 63 64 Output Parameter: 65 . F - output vector 66 67 Note: 68 The Galerkin FAS function evalutation is defined as 69 $ F^l(x^l) = I^l_0 F^0(P^0_l x^l) 70 71 Level: developer 72 73 .seealso: `SNESFAS`, `SNESFASGetGalerkin()`, `SNESFASSetGalerkin()` 74 @*/ 75 PetscErrorCode SNESFASGalerkinFunctionDefault(SNES snes, Vec X, Vec F, void *ctx) 76 { 77 SNES fassnes; 78 SNES_FAS *fas; 79 SNES_FAS *prevfas; 80 SNES prevsnes; 81 Vec b_temp; 82 83 PetscFunctionBegin; 84 /* prolong to the fine level and evaluate there. */ 85 fassnes = (SNES)ctx; 86 fas = (SNES_FAS *)fassnes->data; 87 prevsnes = fas->previous; 88 prevfas = (SNES_FAS *)prevsnes->data; 89 /* interpolate down the solution */ 90 PetscCall(MatInterpolate(prevfas->interpolate, X, prevfas->Xg)); 91 /* the RHS we care about is at the coarsest level */ 92 b_temp = prevsnes->vec_rhs; 93 prevsnes->vec_rhs = NULL; 94 PetscCall(SNESComputeFunction(prevsnes, prevfas->Xg, prevfas->Fg)); 95 prevsnes->vec_rhs = b_temp; 96 /* restrict up the function */ 97 PetscCall(MatRestrict(prevfas->restrct, prevfas->Fg, F)); 98 PetscFunctionReturn(0); 99 } 100