2: static char help[] = "Model multi-physics solver\n\n";

  4: /*
  5:      A model "multi-physics" solver based on the Vincent Mousseau's reactor core pilot code.

  7:      There a three grids:

  9:             ----------------------     ---------------
 10:        |   |                     /    /              /
 11:        |   |                     /    /              /
 12:        |   |                     /    /              /
 13:        |   |                     /    /              /
 14:        |   |                     /    /              /
 15:             ----------------------     ---------------

 17:    A 1d grid along the left edge, a 2d grid in the middle and another 2d grid on the right.

 19: */

 21:  #include petscdmmg.h



 29: int main(int argc,char **argv)
 30: {
 31:   DMMG           *dmmg;               /* multilevel grid structure */
 33:   MPI_Comm       comm;
 34:   DA             da;
 35:   VecPack        pack;

 37:   PetscInitialize(&argc,&argv,(char *)0,help);
 38:   comm = PETSC_COMM_WORLD;


 41:   PreLoadBegin(PETSC_TRUE,"SetUp");

 43:     /*
 44:        Create the VecPack object to manage the three grids/physics. 
 45:        We only support a 1d decomposition along the y direction (since one of the grids is 1d).

 47:     */
 48:     VecPackCreate(comm,&pack);
 49:     DACreate1d(comm,DA_NONPERIODIC,-6,1,1,0,&da);
 50:     VecPackAddDA(pack,da);
 51:     DADestroy(da);
 52:     DACreate2d(comm,DA_NONPERIODIC,DA_STENCIL_STAR,-6,-6,1,PETSC_DETERMINE,1,1,0,0,&da);
 53:     VecPackAddDA(pack,da);
 54:     DADestroy(da);
 55:     DACreate2d(comm,DA_NONPERIODIC,DA_STENCIL_STAR,-6,-6,1,PETSC_DETERMINE,1,1,0,0,&da);
 56:     VecPackAddDA(pack,da);
 57:     DADestroy(da);
 58: 
 59:     /*
 60:        Create the solver object and attach the grid/physics info 
 61:     */
 62:     DMMGCreate(comm,2,0,&dmmg);
 63:     DMMGSetDM(dmmg,(DM)pack);
 64:     VecPackDestroy(pack);
 65:     CHKMEMQ;


 68:     DMMGSetInitialGuessLocal(dmmg,(PetscErrorCode (*)(void)) FormInitialGuessLocal);
 69:     CHKMEMQ;
 70:     DMMGSetSNESLocal(dmmg,(PetscErrorCode (*)(void))0,0,0,0);
 71:     CHKMEMQ;

 73:     /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 74:        Solve the nonlinear system
 75:        - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 77:   PreLoadStage("Solve");
 78:     DMMGSolve(dmmg);

 80:     /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 81:        Free work space.  All PETSc objects should be destroyed when they
 82:        are no longer needed.
 83:        - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 85:     DMMGDestroy(dmmg);
 86:   PreLoadEnd();

 88:   PetscFinalize();
 89:   return 0;
 90: }

 92: /* ------------------------------------------------------------------- */


 97: /* 
 98:    FormInitialGuessLocal - Forms initial approximation.

100:    Input Parameters:
101:    user - user-defined application context
102:    X - vector

104:    Output Parameter:
105:    X - vector
106:  */
107: PetscErrorCode FormInitialGuessLocal(DALocalInfo *info1,PetscScalar *x1,DALocalInfo *info2,PetscScalar **x2,DALocalInfo *info3,PetscScalar **x3)
108: {
109:   PetscInt       i;
110:   PetscReal      hx,dhx;

113:   dhx = (PetscReal)(info1->mx-1);
114:   hx = 1.0/dhx;

116:   for (i=info1->xs; i<info1->xs+info1->xm; i++) {
117:     x1[i]   = 22.3;
118:   }
119:   return(0);
120: }
121: