PetscErrorCode FormInitial(PetscReal t, Vec X, void *ctx)
{
PetscScalar *x;
AppCtx *app = (AppCtx*) ctx;
PetscErrorCode ierr;
PetscFunctionBegin;
ierr = VecGetArray(X,&x);CHKERRQ(ierr);
/**/
formInitial(&app->nx,&app->ny,&app->nz,app->h,
&t,x);
/**/
ierr = VecRestoreArray(X,&x);CHKERRQ(ierr);
PetscFunctionReturn(0);
}
int main(int argc,char **argv) {
PetscErrorCode ierr;
SNES snes;
Vec u;
DMDALocalInfo info;
Ctx user;
PetscInitialize(&argc,&argv,(char*)0,help);
ierr = configureCtx(&user); CHKERRQ(ierr);
ierr = DMDACreate2d(PETSC_COMM_WORLD,
DM_BOUNDARY_NONE, DM_BOUNDARY_NONE,
DMDA_STENCIL_STAR,
-3,-3,
PETSC_DECIDE,PETSC_DECIDE,
1,1,
NULL,NULL,
&user.da); CHKERRQ(ierr);
ierr = DMDASetUniformCoordinates(user.da,-1.0,1.0,-1.0,1.0,0.0,1.0); CHKERRQ(ierr);
ierr = DMSetApplicationContext(user.da,&user); CHKERRQ(ierr);
ierr = DMDAGetLocalInfo(user.da,&info); CHKERRQ(ierr);
if ((info.mx < 2) || (info.my < 2)) {
SETERRQ(PETSC_COMM_WORLD,1,"grid too coarse ... require (mx,my) > (2,2)");
}
ierr = DMCreateGlobalVector(user.da,&u); CHKERRQ(ierr);
ierr = PetscObjectSetName((PetscObject)u,"u_vec");CHKERRQ(ierr);
ierr = formInitial(&info,&user,u); CHKERRQ(ierr);
ierr = SNESCreate(PETSC_COMM_WORLD,&snes);CHKERRQ(ierr);
ierr = SNESSetDM(snes,user.da);CHKERRQ(ierr);
ierr = DMDASNESSetFunctionLocal(user.da,INSERT_VALUES,
(DMDASNESFunction)FormFunctionLocal,&user);CHKERRQ(ierr);
ierr = DMDASNESSetJacobianLocal(user.da,
(DMDASNESJacobian)FormJacobianLocal,&user);CHKERRQ(ierr);
ierr = SNESSetFromOptions(snes);CHKERRQ(ierr);
ierr = SNESSolve(snes,NULL,u); CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD,
"done on %d x %d x %d grid with eps=%g ...\n",
info.mx,info.my,info.mz,user.eps); CHKERRQ(ierr);
VecDestroy(&u);
SNESDestroy(&snes); DMDestroy(&user.da);
ierr = PetscFinalize(); CHKERRQ(ierr);
return 0;
}
