int main(int argc,char **argv)
{
TS ts; /* nonlinear solver */
Vec x,r; /* solution, residual vectors */
Mat J; /* Jacobian matrix */
PetscInt steps,Mx,maxsteps = 10000000;
PetscErrorCode ierr;
DM da;
MatFDColoring matfdcoloring;
ISColoring iscoloring;
PetscReal dt;
PetscReal vbounds[] = {-100000,100000,-1.1,1.1};
PetscBool wait;
Vec ul,uh;
SNES snes;
UserCtx ctx;
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Initialize program
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = PetscInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
ctx.kappa = 1.0;
ierr = PetscOptionsGetReal(NULL,"-kappa",&ctx.kappa,NULL);CHKERRQ(ierr);
ctx.cahnhillard = PETSC_FALSE;
ierr = PetscOptionsGetBool(NULL,NULL,"-cahn-hillard",&ctx.cahnhillard,NULL);CHKERRQ(ierr);
ierr = PetscViewerDrawSetBounds(PETSC_VIEWER_DRAW_(PETSC_COMM_WORLD),2,vbounds);CHKERRQ(ierr);
ierr = PetscViewerDrawResize(PETSC_VIEWER_DRAW_(PETSC_COMM_WORLD),600,600);CHKERRQ(ierr);
ctx.energy = 1;
/* ierr = PetscOptionsGetInt(NULL,NULL,"-energy",&ctx.energy,NULL);CHKERRQ(ierr); */
ierr = PetscOptionsGetInt(NULL,NULL,"-energy",&ctx.energy,NULL);CHKERRQ(ierr);
ctx.tol = 1.0e-8;
ierr = PetscOptionsGetReal(NULL,"-tol",&ctx.tol,NULL);CHKERRQ(ierr);
ctx.theta = .001;
ctx.theta_c = 1.0;
ierr = PetscOptionsGetReal(NULL,"-theta",&ctx.theta,NULL);CHKERRQ(ierr);
ierr = PetscOptionsGetReal(NULL,"-theta_c",&ctx.theta_c,NULL);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Create distributed array (DMDA) to manage parallel grid and vectors
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = DMDACreate1d(PETSC_COMM_WORLD, DM_BOUNDARY_PERIODIC, -10,2,2,NULL,&da);CHKERRQ(ierr);
ierr = DMSetFromOptions(da);CHKERRQ(ierr);
ierr = DMSetUp(da);CHKERRQ(ierr);
ierr = DMDASetFieldName(da,0,"Biharmonic heat equation: w = -kappa*u_xx");CHKERRQ(ierr);
ierr = DMDASetFieldName(da,1,"Biharmonic heat equation: u");CHKERRQ(ierr);
ierr = DMDAGetInfo(da,0,&Mx,0,0,0,0,0,0,0,0,0,0,0);CHKERRQ(ierr);
dt = 1.0/(10.*ctx.kappa*Mx*Mx*Mx*Mx);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Extract global vectors from DMDA; then duplicate for remaining
vectors that are the same types
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = DMCreateGlobalVector(da,&x);CHKERRQ(ierr);
ierr = VecDuplicate(x,&r);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Create timestepping solver context
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = TSCreate(PETSC_COMM_WORLD,&ts);CHKERRQ(ierr);
ierr = TSSetDM(ts,da);CHKERRQ(ierr);
ierr = TSSetProblemType(ts,TS_NONLINEAR);CHKERRQ(ierr);
ierr = TSSetIFunction(ts,NULL,FormFunction,&ctx);CHKERRQ(ierr);
ierr = TSSetDuration(ts,maxsteps,.02);CHKERRQ(ierr);
ierr = TSSetExactFinalTime(ts,TS_EXACTFINALTIME_STEPOVER);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Create matrix data structure; set Jacobian evaluation routine
< Set Jacobian matrix data structure and default Jacobian evaluation
routine. User can override with:
-snes_mf : matrix-free Newton-Krylov method with no preconditioning
(unless user explicitly sets preconditioner)
-snes_mf_operator : form preconditioning matrix as set by the user,
but use matrix-free approx for Jacobian-vector
products within Newton-Krylov method
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
ierr = DMCreateColoring(da,IS_COLORING_GLOBAL,&iscoloring);CHKERRQ(ierr);
ierr = DMSetMatType(da,MATAIJ);CHKERRQ(ierr);
ierr = DMCreateMatrix(da,&J);CHKERRQ(ierr);
ierr = MatFDColoringCreate(J,iscoloring,&matfdcoloring);CHKERRQ(ierr);
ierr = ISColoringDestroy(&iscoloring);CHKERRQ(ierr);
ierr = MatFDColoringSetFunction(matfdcoloring,(PetscErrorCode (*)(void))SNESTSFormFunction,ts);CHKERRQ(ierr);
ierr = MatFDColoringSetFromOptions(matfdcoloring);CHKERRQ(ierr);
ierr = MatFDColoringSetUp(J,iscoloring,matfdcoloring);CHKERRQ(ierr);
ierr = SNESSetJacobian(snes,J,J,SNESComputeJacobianDefaultColor,matfdcoloring);CHKERRQ(ierr);
{
ierr = VecDuplicate(x,&ul);CHKERRQ(ierr);
ierr = VecDuplicate(x,&uh);CHKERRQ(ierr);
ierr = VecStrideSet(ul,0,PETSC_NINFINITY);CHKERRQ(ierr);
ierr = VecStrideSet(ul,1,-1.0);CHKERRQ(ierr);
ierr = VecStrideSet(uh,0,PETSC_INFINITY);CHKERRQ(ierr);
ierr = VecStrideSet(uh,1,1.0);CHKERRQ(ierr);
ierr = TSVISetVariableBounds(ts,ul,uh);CHKERRQ(ierr);
}
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Customize nonlinear solver
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = TSSetType(ts,TSBEULER);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Set initial conditions
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = FormInitialSolution(da,x,ctx.kappa);CHKERRQ(ierr);
ierr = TSSetInitialTimeStep(ts,0.0,dt);CHKERRQ(ierr);
ierr = TSSetSolution(ts,x);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Set runtime options
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = TSSetFromOptions(ts);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Solve nonlinear system
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = TSSolve(ts,x);CHKERRQ(ierr);
wait = PETSC_FALSE;
ierr = PetscOptionsGetBool(NULL,NULL,"-wait",&wait,NULL);CHKERRQ(ierr);
if (wait) {
ierr = PetscSleep(-1);CHKERRQ(ierr);
}
ierr = TSGetTimeStepNumber(ts,&steps);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Free work space. All PETSc objects should be destroyed when they
are no longer needed.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
{
ierr = VecDestroy(&ul);CHKERRQ(ierr);
ierr = VecDestroy(&uh);CHKERRQ(ierr);
}
ierr = MatDestroy(&J);CHKERRQ(ierr);
ierr = MatFDColoringDestroy(&matfdcoloring);CHKERRQ(ierr);
ierr = VecDestroy(&x);CHKERRQ(ierr);
ierr = VecDestroy(&r);CHKERRQ(ierr);
ierr = TSDestroy(&ts);CHKERRQ(ierr);
ierr = DMDestroy(&da);CHKERRQ(ierr);
ierr = PetscFinalize();
PetscFunctionReturn(0);
}
void PETSC_STDCALL tsvisetvariablebounds_(TS ts,Vec xl,Vec xu, int *__ierr ){
*__ierr = TSVISetVariableBounds(
(TS)PetscToPointer((ts) ),
(Vec)PetscToPointer((xl) ),
(Vec)PetscToPointer((xu) ));
}
