xref: /petsc/src/ts/interface/tscreate.c (revision da9f1d6b25924a16baf1fafcd5e58fa8eaafd3cf)
1 #define PETSCTS_DLL
2 
3 #include "include/private/tsimpl.h"      /*I "petscts.h"  I*/
4 
5 #undef __FUNCT__
6 #define __FUNCT__ "TSPublish_Petsc"
7 static PetscErrorCode TSPublish_Petsc(PetscObject obj)
8 {
9   PetscFunctionBegin;
10   PetscFunctionReturn(0);
11 }
12 
13 #undef  __FUNCT__
14 #define __FUNCT__ "TSCreate"
15 /*@C
16   TSCreate - This function creates an empty timestepper. The problem type can then be set with TSSetProblemType() and the
17        type of solver can then be set with TSSetType().
18 
19   Collective on MPI_Comm
20 
21   Input Parameter:
22 . comm - The communicator
23 
24   Output Parameter:
25 . ts   - The TS
26 
27   Level: beginner
28 
29 .keywords: TS, create
30 .seealso: TSSetType(), TSSetUp(), TSDestroy(), MeshCreate(), TSSetProblemType()
31 @*/
32 PetscErrorCode PETSCTS_DLLEXPORT TSCreate(MPI_Comm comm, TS *ts) {
33   TS             t;
34   PetscErrorCode ierr;
35 
36   PetscFunctionBegin;
37   PetscValidPointer(ts,1);
38   *ts = PETSC_NULL;
39 #ifndef PETSC_USE_DYNAMIC_LIBRARIES
40   ierr = TSInitializePackage(PETSC_NULL);CHKERRQ(ierr);
41 #endif
42 
43   ierr = PetscHeaderCreate(t, _p_TS, struct _TSOps, TS_COOKIE, -1, "TS", comm, TSDestroy, TSView);CHKERRQ(ierr);
44   ierr = PetscMemzero(t->ops, sizeof(struct _TSOps));CHKERRQ(ierr);
45   t->bops->publish    = TSPublish_Petsc;
46   t->type_name        = PETSC_NULL;
47 
48   t->ops->prestep       = TSDefaultPreStep;
49   t->ops->update        = TSDefaultUpdate;
50   t->ops->poststep      = TSDefaultPostStep;
51 
52   /* General TS description */
53   t->problem_type       = TS_LINEAR;
54   t->vec_sol            = PETSC_NULL;
55   t->vec_sol_always     = PETSC_NULL;
56   t->numbermonitors     = 0;
57   t->isExplicit         = PETSC_NULL;
58   t->Iindex             = PETSC_NULL;
59   t->ksp                = PETSC_NULL;
60   t->A                  = PETSC_NULL;
61   t->B                  = PETSC_NULL;
62   t->Arhs               = PETSC_NULL;
63   t->Alhs               = PETSC_NULL;
64   t->matflg             = DIFFERENT_NONZERO_PATTERN;
65   t->snes               = PETSC_NULL;
66   t->funP               = PETSC_NULL;
67   t->jacP               = PETSC_NULL;
68   t->setupcalled        = 0;
69   t->data               = PETSC_NULL;
70   t->user               = PETSC_NULL;
71   t->max_steps          = 5000;
72   t->max_time           = 5.0;
73   t->time_step          = .1;
74   t->time_step_old      = t->time_step;
75   t->initial_time_step  = t->time_step;
76   t->steps              = 0;
77   t->ptime              = 0.0;
78   t->linear_its         = 0;
79   t->nonlinear_its      = 0;
80   t->work               = PETSC_NULL;
81   t->nwork              = 0;
82 
83   *ts = t;
84   PetscFunctionReturn(0);
85 }
86 
87 /* Set A = 1/dt*Alhs - A, B = 1/dt*Blhs - B */
88 #undef __FUNCT__
89 #define __FUNCT__ "TSScaleShiftMatrices"
90 PetscErrorCode TSScaleShiftMatrices(TS ts,Mat A,Mat B,MatStructure str)
91 {
92   PetscTruth     flg;
93   PetscErrorCode ierr;
94   PetscScalar    mdt = 1.0/ts->time_step;
95 
96   PetscFunctionBegin;
97   /* this function requires additional work! */
98   ierr = PetscTypeCompare((PetscObject)A,MATMFFD,&flg);CHKERRQ(ierr);
99   if (!flg) {
100     ierr = MatScale(A,-1.0);CHKERRQ(ierr);
101     if (ts->Alhs){
102       ierr = MatAXPY(A,mdt,ts->Alhs,DIFFERENT_NONZERO_PATTERN);CHKERRQ(ierr);
103     } else {
104       ierr = MatShift(A,mdt);CHKERRQ(ierr);
105     }
106   }
107   if (B != A && str != SAME_PRECONDITIONER) {
108     ierr = MatScale(B,-1.0);CHKERRQ(ierr);
109     ierr = MatShift(B,mdt);CHKERRQ(ierr);
110   }
111   PetscFunctionReturn(0);
112 }
113