1 2 #include <private/snesimpl.h> /*I "petscsnes.h" I*/ 3 #include <../src/mat/impls/mffd/mffdimpl.h> 4 #include <private/matimpl.h> 5 6 #undef __FUNCT__ 7 #define __FUNCT__ "MatMFFDComputeJacobian" 8 /*@C 9 MatMFFDComputeJacobian - Tells the matrix-free Jacobian object the new location at which 10 Jacobian matrix vector products will be computed at, i.e. J(x) * a. The x is obtained 11 from the SNES object (using SNESGetSolution()). 12 13 Logically Collective on SNES 14 15 Input Parameters: 16 + snes - the nonlinear solver context 17 . x - the point at which the Jacobian vector products will be performed 18 . jac - the matrix-free Jacobian object 19 . B - either the same as jac or another matrix type (ignored) 20 . flag - not relevent for matrix-free form 21 - dummy - the user context (ignored) 22 23 Level: developer 24 25 Warning: 26 If MatMFFDSetBase() is ever called on jac then this routine will NO longer get 27 the x from the SNES object and MatMFFDSetBase() must from that point on be used to 28 change the base vector x. 29 30 Notes: 31 This can be passed into SNESSetJacobian() when using a completely matrix-free solver, 32 that is the B matrix is also the same matrix operator. This is used when you select 33 -snes_mf but rarely used directly by users. (All this routine does is call MatAssemblyBegin/End() on 34 the Mat jac. 35 36 .seealso: MatMFFDGetH(), MatCreateSNESMF(), MatCreateMFFD(), MATMFFD, 37 MatMFFDSetHHistory(), MatMFFDSetFunctionError(), MatCreateMFFD(), SNESSetJacobian() 38 39 @*/ 40 PetscErrorCode MatMFFDComputeJacobian(SNES snes,Vec x,Mat *jac,Mat *B,MatStructure *flag,void *dummy) 41 { 42 PetscErrorCode ierr; 43 PetscFunctionBegin; 44 ierr = MatAssemblyBegin(*jac,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr); 45 ierr = MatAssemblyEnd(*jac,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr); 46 PetscFunctionReturn(0); 47 } 48 49 PetscErrorCode MatAssemblyEnd_MFFD(Mat,MatAssemblyType); 50 EXTERN_C_BEGIN 51 PetscErrorCode MatMFFDSetBase_MFFD(Mat,Vec,Vec); 52 EXTERN_C_END 53 54 #undef __FUNCT__ 55 #define __FUNCT__ "MatAssemblyEnd_SNESMF" 56 /* 57 MatAssemblyEnd_SNESMF - Calls MatAssemblyEnd_MFFD() and then sets the 58 base from the SNES context 59 60 */ 61 PetscErrorCode MatAssemblyEnd_SNESMF(Mat J,MatAssemblyType mt) 62 { 63 PetscErrorCode ierr; 64 MatMFFD j = (MatMFFD)J->data; 65 SNES snes = (SNES)j->funcctx; 66 Vec u,f; 67 68 PetscFunctionBegin; 69 ierr = MatAssemblyEnd_MFFD(J,mt);CHKERRQ(ierr); 70 71 ierr = SNESGetSolution(snes,&u);CHKERRQ(ierr); 72 ierr = SNESGetFunction(snes,&f,PETSC_NULL,PETSC_NULL);CHKERRQ(ierr); 73 ierr = MatMFFDSetBase_MFFD(J,u,f);CHKERRQ(ierr); 74 PetscFunctionReturn(0); 75 } 76 77 EXTERN_C_BEGIN 78 /* 79 This routine resets the MatAssemblyEnd() for the MatMFFD created from MatCreateSNESMF() so that it NO longer 80 uses the solution in the SNES object to update the base. See the warning in MatCreateSNESMF(). 81 */ 82 #undef __FUNCT__ 83 #define __FUNCT__ "MatMFFDSetBase_SNESMF" 84 PetscErrorCode MatMFFDSetBase_SNESMF(Mat J,Vec U,Vec F) 85 { 86 PetscErrorCode ierr; 87 88 PetscFunctionBegin; 89 ierr = MatMFFDSetBase_MFFD(J,U,F);CHKERRQ(ierr); 90 J->ops->assemblyend = MatAssemblyEnd_MFFD; 91 PetscFunctionReturn(0); 92 } 93 EXTERN_C_END 94 95 #undef __FUNCT__ 96 #define __FUNCT__ "MatCreateSNESMF" 97 /*@ 98 MatCreateSNESMF - Creates a matrix-free matrix context for use with 99 a SNES solver. This matrix can be used as the Jacobian argument for 100 the routine SNESSetJacobian(). See MatCreateMFFD() for details on how 101 the finite difference computation is done. 102 103 Collective on SNES and Vec 104 105 Input Parameters: 106 . snes - the SNES context 107 108 Output Parameter: 109 . J - the matrix-free matrix 110 111 Level: advanced 112 113 Warning: 114 If MatMFFDSetBase() is ever called on jac then this routine will NO longer get 115 the x from the SNES object and MatMFFDSetBase() must from that point on be used to 116 change the base vector x. 117 118 Notes: The difference between this routine and MatCreateMFFD() is that this matrix 119 automatically gets the current base vector from the SNES object and not from an 120 explicit call to MatMFFDSetBase(). 121 122 .seealso: MatDestroy(), MatMFFDSetFunctionError(), MatMFFDDSSetUmin() 123 MatMFFDSetHHistory(), MatMFFDResetHHistory(), MatCreateMFFD(), 124 MatMFFDGetH(), MatMFFDRegisterDynamic), MatMFFDComputeJacobian() 125 126 @*/ 127 PetscErrorCode MatCreateSNESMF(SNES snes,Mat *J) 128 { 129 PetscErrorCode ierr; 130 PetscInt n,N; 131 132 PetscFunctionBegin; 133 if (snes->vec_func) { 134 ierr = VecGetLocalSize(snes->vec_func,&n);CHKERRQ(ierr); 135 ierr = VecGetSize(snes->vec_func,&N);CHKERRQ(ierr); 136 } else if (snes->dm) { 137 Vec tmp; 138 ierr = DMGetGlobalVector(snes->dm,&tmp);CHKERRQ(ierr); 139 ierr = VecGetLocalSize(tmp,&n);CHKERRQ(ierr); 140 ierr = VecGetSize(tmp,&N);CHKERRQ(ierr); 141 ierr = DMRestoreGlobalVector(snes->dm,&tmp);CHKERRQ(ierr); 142 } else SETERRQ(((PetscObject)snes)->comm,PETSC_ERR_ARG_WRONGSTATE,"Must call SNESSetFunction() or SNESSetDM() first"); 143 ierr = MatCreateMFFD(((PetscObject)snes)->comm,n,n,N,N,J);CHKERRQ(ierr); 144 ierr = MatMFFDSetFunction(*J,(PetscErrorCode (*)(void*,Vec,Vec))SNESComputeFunction,snes);CHKERRQ(ierr); 145 (*J)->ops->assemblyend = MatAssemblyEnd_SNESMF; 146 ierr = PetscObjectComposeFunctionDynamic((PetscObject)*J,"MatMFFDSetBase_C","MatMFFDSetBase_SNESMF",MatMFFDSetBase_SNESMF);CHKERRQ(ierr); 147 PetscFunctionReturn(0); 148 } 149 150 151 152 153 154 155