1 2 #include <petsc-private/snesimpl.h> /*I "petscsnes.h" I*/ 3 #include <petscdm.h> /*I "petscdm.h" I*/ 4 #include <../src/mat/impls/mffd/mffdimpl.h> 5 #include <petsc-private/matimpl.h> 6 7 #undef __FUNCT__ 8 #define __FUNCT__ "MatMFFDComputeJacobian" 9 /*@C 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 Logically 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() as the Jacobian evaluation function argument 33 when using a completely matrix-free solver, 34 that is the B matrix is also the same matrix operator. This is used when you select 35 -snes_mf but rarely used directly by users. (All this routine does is call MatAssemblyBegin/End() on 36 the Mat jac. 37 38 .seealso: MatMFFDGetH(), MatCreateSNESMF(), MatCreateMFFD(), MATMFFD, 39 MatMFFDSetHHistory(), MatMFFDSetFunctionError(), MatCreateMFFD(), SNESSetJacobian() 40 41 @*/ 42 PetscErrorCode MatMFFDComputeJacobian(SNES snes,Vec x,Mat *jac,Mat *B,MatStructure *flag,void *dummy) 43 { 44 PetscErrorCode ierr; 45 46 PetscFunctionBegin; 47 ierr = MatAssemblyBegin(*jac,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr); 48 ierr = MatAssemblyEnd(*jac,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr); 49 PetscFunctionReturn(0); 50 } 51 52 PETSC_EXTERN PetscErrorCode MatAssemblyEnd_MFFD(Mat,MatAssemblyType); 53 PETSC_EXTERN_C PetscErrorCode MatMFFDSetBase_MFFD(Mat,Vec,Vec); 54 55 #undef __FUNCT__ 56 #define __FUNCT__ "MatAssemblyEnd_SNESMF" 57 /* 58 MatAssemblyEnd_SNESMF - Calls MatAssemblyEnd_MFFD() and then sets the 59 base from the SNES context 60 61 */ 62 PetscErrorCode MatAssemblyEnd_SNESMF(Mat J,MatAssemblyType mt) 63 { 64 PetscErrorCode ierr; 65 MatMFFD j = (MatMFFD)J->data; 66 SNES snes = (SNES)j->funcctx; 67 Vec u,f; 68 69 PetscFunctionBegin; 70 ierr = MatAssemblyEnd_MFFD(J,mt);CHKERRQ(ierr); 71 72 ierr = SNESGetSolution(snes,&u);CHKERRQ(ierr); 73 ierr = SNESGetFunction(snes,&f,NULL,NULL);CHKERRQ(ierr); 74 ierr = MatMFFDSetBase_MFFD(J,u,f);CHKERRQ(ierr); 75 PetscFunctionReturn(0); 76 } 77 78 EXTERN_C_BEGIN 79 /* 80 This routine resets the MatAssemblyEnd() for the MatMFFD created from MatCreateSNESMF() so that it NO longer 81 uses the solution in the SNES object to update the base. See the warning in MatCreateSNESMF(). 82 */ 83 #undef __FUNCT__ 84 #define __FUNCT__ "MatMFFDSetBase_SNESMF" 85 PetscErrorCode MatMFFDSetBase_SNESMF(Mat J,Vec U,Vec F) 86 { 87 PetscErrorCode ierr; 88 89 PetscFunctionBegin; 90 ierr = MatMFFDSetBase_MFFD(J,U,F);CHKERRQ(ierr); 91 92 J->ops->assemblyend = MatAssemblyEnd_MFFD; 93 PetscFunctionReturn(0); 94 } 95 EXTERN_C_END 96 97 #undef __FUNCT__ 98 #define __FUNCT__ "MatCreateSNESMF" 99 /*@ 100 MatCreateSNESMF - Creates a matrix-free matrix context for use with 101 a SNES solver. This matrix can be used as the Jacobian argument for 102 the routine SNESSetJacobian(). See MatCreateMFFD() for details on how 103 the finite difference computation is done. 104 105 Collective on SNES and Vec 106 107 Input Parameters: 108 . snes - the SNES context 109 110 Output Parameter: 111 . J - the matrix-free matrix 112 113 Level: advanced 114 115 Warning: 116 If MatMFFDSetBase() is ever called on jac then this routine will NO longer get 117 the x from the SNES object and MatMFFDSetBase() must from that point on be used to 118 change the base vector x. 119 120 Notes: The difference between this routine and MatCreateMFFD() is that this matrix 121 automatically gets the current base vector from the SNES object and not from an 122 explicit call to MatMFFDSetBase(). 123 124 .seealso: MatDestroy(), MatMFFDSetFunctionError(), MatMFFDDSSetUmin() 125 MatMFFDSetHHistory(), MatMFFDResetHHistory(), MatCreateMFFD(), 126 MatMFFDGetH(), MatMFFDRegisterDynamic), MatMFFDComputeJacobian() 127 128 @*/ 129 PetscErrorCode MatCreateSNESMF(SNES snes,Mat *J) 130 { 131 PetscErrorCode ierr; 132 PetscInt n,N; 133 134 PetscFunctionBegin; 135 if (snes->vec_func) { 136 ierr = VecGetLocalSize(snes->vec_func,&n);CHKERRQ(ierr); 137 ierr = VecGetSize(snes->vec_func,&N);CHKERRQ(ierr); 138 } else if (snes->dm) { 139 Vec tmp; 140 ierr = DMGetGlobalVector(snes->dm,&tmp);CHKERRQ(ierr); 141 ierr = VecGetLocalSize(tmp,&n);CHKERRQ(ierr); 142 ierr = VecGetSize(tmp,&N);CHKERRQ(ierr); 143 ierr = DMRestoreGlobalVector(snes->dm,&tmp);CHKERRQ(ierr); 144 } else SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_WRONGSTATE,"Must call SNESSetFunction() or SNESSetDM() first"); 145 ierr = MatCreateMFFD(PetscObjectComm((PetscObject)snes),n,n,N,N,J);CHKERRQ(ierr); 146 ierr = MatMFFDSetFunction(*J,(PetscErrorCode (*)(void*,Vec,Vec))SNESComputeFunction,snes);CHKERRQ(ierr); 147 148 (*J)->ops->assemblyend = MatAssemblyEnd_SNESMF; 149 150 ierr = PetscObjectComposeFunction((PetscObject)*J,"MatMFFDSetBase_C","MatMFFDSetBase_SNESMF",MatMFFDSetBase_SNESMF);CHKERRQ(ierr); 151 PetscFunctionReturn(0); 152 } 153 154 155 156 157 158 159