1 #define PETSCSNES_DLL 2 3 #include "include/private/snesimpl.h" /*I "petscsnes.h" I*/ 4 #include "include/private/matimpl.h" 5 #include "src/mat/impls/mffd/mffdimpl.h" 6 7 #undef __FUNCT__ 8 #define __FUNCT__ "MatMFFDComputeJacobian" 9 /*@ 10 MatMFFDComputeJacobian - Tells the matrix-free Jacobian object the new location at which 11 Jacobian matrix vector products will be computed at, i.e. J(x) * a. The x is obtained 12 from the SNES object (using SNESGetSolution()). 13 14 Collective on SNES 15 16 Input Parameters: 17 + snes - the nonlinear solver context 18 . x - the point at which the Jacobian vector products will be performed 19 . jac - the matrix-free Jacobian object 20 . B - either the same as jac or another matrix type (ignored) 21 . flag - not relevent for matrix-free form 22 - dummy - the user context (ignored) 23 24 Level: developer 25 26 Warning: 27 If MatMFFDSetBase() is ever called on jac then this routine will NO longer get 28 the x from the SNES object and MatMFFDSetBase() must from that point on be used to 29 change the base vector x. 30 31 Notes: 32 This can be passed into SNESSetJacobian() when using a completely matrix-free solver, 33 that is the B matrix is also the same matrix operator. This is used when you select 34 -snes_mf but rarely used directly by users. 35 36 .seealso: MatMFFDGetH(), MatCreateSNESMF(), MatCreateMFFD(), MATMFFD, 37 MatMFFDSetHHistory(), 38 MatMFFDKSPMonitor(), MatMFFDSetFunctionError(), MatMFFDCreate(), SNESSetJacobian() 39 40 @*/ 41 PetscErrorCode PETSCSNES_DLLEXPORT MatMFFDComputeJacobian(SNES snes,Vec x,Mat *jac,Mat *B,MatStructure *flag,void *dummy) 42 { 43 PetscErrorCode ierr; 44 PetscFunctionBegin; 45 ierr = MatAssemblyBegin(*jac,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr); 46 ierr = MatAssemblyEnd(*jac,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr); 47 PetscFunctionReturn(0); 48 } 49 50 PetscErrorCode MatAssemblyEnd_MFFD(Mat,MatAssemblyType); 51 #undef __FUNCT__ 52 #define __FUNCT__ "MatAssemblyEnd_SNESMF" 53 /* 54 MatAssemblyEnd_SNESMF - Calls MatAssemblyEnd_MFFD() and then sets the 55 base from the SNES context 56 57 */ 58 PetscErrorCode MatAssemblyEnd_SNESMF(Mat J,MatAssemblyType mt) 59 { 60 PetscErrorCode ierr; 61 MatMFFD j = (MatMFFD)J->data; 62 SNES snes = (SNES)j->funcctx; 63 Vec u,f; 64 65 PetscFunctionBegin; 66 ierr = MatAssemblyEnd_MFFD(J,mt);CHKERRQ(ierr); 67 68 ierr = SNESGetSolution(snes,&u);CHKERRQ(ierr); 69 ierr = SNESGetFunction(snes,&f,PETSC_NULL,PETSC_NULL);CHKERRQ(ierr); 70 ierr = MatMFFDSetBase(J,u,f);CHKERRQ(ierr); 71 PetscFunctionReturn(0); 72 } 73 74 EXTERN_C_BEGIN 75 extern PetscErrorCode PETSCMAT_DLLEXPORT MatMFFDSetBase_MFFD(Mat,Vec,Vec); 76 /* 77 This routine resets the MatAssemblyEnd() for the MatMFFD created from MatCreateSNESMF() so that it NO longer 78 uses the solution in the SNES object to update the base. See the warning in MatCreateSNESMF(). 79 */ 80 #undef __FUNCT__ 81 #define __FUNCT__ "MatMFFDSetBase_SNESMF" 82 PetscErrorCode PETSCMAT_DLLEXPORT MatMFFDSetBase_SNESMF(Mat J,Vec U,Vec F) 83 { 84 PetscErrorCode ierr; 85 86 PetscFunctionBegin; 87 ierr = MatMFFDSetBase_MFFD(J,U,F);CHKERRQ(ierr); 88 J->ops->assemblyend = MatAssemblyEnd_MFFD; 89 PetscFunctionReturn(0); 90 } 91 EXTERN_C_END 92 93 #undef __FUNCT__ 94 #define __FUNCT__ "MatCreateSNESMF" 95 /*@ 96 MatCreateSNESMF - Creates a matrix-free matrix context for use with 97 a SNES solver. This matrix can be used as the Jacobian argument for 98 the routine SNESSetJacobian(). See MatCreateMFFD() for details on how 99 the finite difference computation is done. 100 101 Collective on SNES and Vec 102 103 Input Parameters: 104 . snes - the SNES context 105 106 Output Parameter: 107 . J - the matrix-free matrix 108 109 Level: advanced 110 111 Warning: 112 If MatMFFDSetBase() is ever called on jac then this routine will NO longer get 113 the x from the SNES object and MatMFFDSetBase() must from that point on be used to 114 change the base vector x. 115 116 Notes: The difference between this routine and MatCreateMFFD() is that this matrix 117 automatically gets the current base vector from the SNES object and not from an 118 explicit call to MatMFFDSetBase(). 119 120 .seealso: MatDestroy(), MatMFFDSetFunctionError(), MatMFFDDefaultSetUmin() 121 MatMFFDSetHHistory(), MatMFFDResetHHistory(), MatCreateMFFD(), 122 MatMFFDGetH(),MatMFFDKSPMonitor(), MatMFFDRegisterDynamic), MatMFFDComputeJacobian() 123 124 @*/ 125 PetscErrorCode PETSCSNES_DLLEXPORT MatCreateSNESMF(SNES snes,Mat *J) 126 { 127 PetscErrorCode ierr; 128 PetscInt n,N; 129 130 PetscFunctionBegin; 131 if (!snes->vec_func) SETERRQ(PETSC_ERR_ARG_WRONGSTATE,"SNESSetFunction() must be called first"); 132 133 ierr = VecGetLocalSize(snes->vec_func,&n);CHKERRQ(ierr); 134 ierr = VecGetSize(snes->vec_func,&N);CHKERRQ(ierr); 135 ierr = MatCreateMFFD(((PetscObject)snes)->comm,n,n,N,N,J);CHKERRQ(ierr); 136 ierr = MatMFFDSetFunction(*J,(PetscErrorCode (*)(void*,Vec,Vec))SNESComputeFunction,snes);CHKERRQ(ierr); 137 (*J)->ops->assemblyend = MatAssemblyEnd_SNESMF; 138 ierr = PetscObjectComposeFunctionDynamic((PetscObject)*J,"MatMFFDSetBase_C","MatMFFDSetBase_SNESMF",MatMFFDSetBase_SNESMF);CHKERRQ(ierr); 139 PetscFunctionReturn(0); 140 } 141 142 143 144 145 146 147