PETSC_EXTERN PetscErrorCode TSCreate_BEuler(TS ts)
{
PetscErrorCode ierr;
PetscFunctionBegin;
ierr = TSCreate_Theta(ts);CHKERRQ(ierr);
ierr = TSThetaSetTheta(ts,1.0);CHKERRQ(ierr);
ts->ops->view = TSView_BEuler;
PetscFunctionReturn(0);
}
PETSC_EXTERN PetscErrorCode TSCreate_CN(TS ts)
{
PetscErrorCode ierr;
PetscFunctionBegin;
ierr = TSCreate_Theta(ts);CHKERRQ(ierr);
ierr = TSThetaSetTheta(ts,0.5);CHKERRQ(ierr);
ierr = TSThetaSetEndpoint(ts,PETSC_TRUE);CHKERRQ(ierr);
ts->ops->view = TSView_CN;
PetscFunctionReturn(0);
}
PetscErrorCode RunTest(int nx, int ny, int nz, int loops, double *wt)
{
Vec x,f;
TS ts;
AppCtx _app,*app=&_app;
double t1,t2;
PetscErrorCode ierr;
PetscFunctionBegin;
app->nx = nx; app->h[0] = 1./(nx-1);
app->ny = ny; app->h[1] = 1./(ny-1);
app->nz = nz; app->h[2] = 1./(nz-1);
ierr = VecCreate(PETSC_COMM_SELF,&x);CHKERRQ(ierr);
ierr = VecSetSizes(x,nx*ny*nz,nx*ny*nz);CHKERRQ(ierr);
ierr = VecSetUp(x);CHKERRQ(ierr);
ierr = VecDuplicate(x,&f);CHKERRQ(ierr);
ierr = TSCreate(PETSC_COMM_SELF,&ts);CHKERRQ(ierr);
ierr = TSSetProblemType(ts,TS_NONLINEAR);CHKERRQ(ierr);
ierr = TSSetType(ts,TSTHETA);CHKERRQ(ierr);
ierr = TSThetaSetTheta(ts,1.0);CHKERRQ(ierr);
ierr = TSSetTimeStep(ts,0.01);CHKERRQ(ierr);
ierr = TSSetTime(ts,0.0);CHKERRQ(ierr);
ierr = TSSetDuration(ts,10,1.0);CHKERRQ(ierr);
ierr = TSSetSolution(ts,x);CHKERRQ(ierr);
ierr = TSSetIFunction(ts,f,FormFunction,app);CHKERRQ(ierr);
ierr = PetscOptionsSetValue("-snes_mf","1");CHKERRQ(ierr);
{
SNES snes;
KSP ksp;
ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
ierr = SNESGetKSP(snes,&ksp);CHKERRQ(ierr);
ierr = KSPSetType(ksp,KSPCG);CHKERRQ(ierr);
}
ierr = TSSetFromOptions(ts);CHKERRQ(ierr);
ierr = TSSetUp(ts);CHKERRQ(ierr);
*wt = 1e300;
while (loops-- > 0) {
ierr = FormInitial(0.0,x,app);CHKERRQ(ierr);
ierr = PetscGetTime(&t1);CHKERRQ(ierr);
ierr = TSSolve(ts,x,PETSC_NULL);CHKERRQ(ierr);
ierr = PetscGetTime(&t2);CHKERRQ(ierr);
*wt = PetscMin(*wt,t2-t1);
}
ierr = VecDestroy(&x);CHKERRQ(ierr);
ierr = VecDestroy(&f);CHKERRQ(ierr);
ierr = TSDestroy(&ts);CHKERRQ(ierr);
PetscFunctionReturn(0);
}
/*MC
TSBEULER - ODE solver using the implicit backward Euler method
Level: beginner
.seealso: TSCreate(), TS, TSSetType(), TSEULER, TSCN, TSTHETA
M*/
EXTERN_C_BEGIN
#undef __FUNCT__
#define __FUNCT__ "TSCreate_BEuler"
PetscErrorCode TSCreate_BEuler(TS ts)
{
PetscErrorCode ierr;
PetscFunctionBegin;
ierr = TSCreate_Theta(ts);CHKERRQ(ierr);
ierr = TSThetaSetTheta(ts,1.0);CHKERRQ(ierr);
ts->ops->view = TSView_BEuler;
PetscFunctionReturn(0);
}
/*MC
TSCN - ODE solver using the implicit Crank-Nicolson method.
Level: beginner
Notes:
TSCN is equivalent to TSTHETA with Theta=0.5 and the "endpoint" option set. I.e.
$ -ts_type theta -ts_theta_theta 0.5 -ts_theta_endpoint
.seealso: TSCreate(), TS, TSSetType(), TSBEULER, TSTHETA
M*/
EXTERN_C_BEGIN
#undef __FUNCT__
#define __FUNCT__ "TSCreate_CN"
PetscErrorCode TSCreate_CN(TS ts)
{
PetscErrorCode ierr;
PetscFunctionBegin;
ierr = TSCreate_Theta(ts);CHKERRQ(ierr);
ierr = TSThetaSetTheta(ts,0.5);CHKERRQ(ierr);
ierr = TSThetaSetEndpoint(ts,PETSC_TRUE);CHKERRQ(ierr);
ts->ops->view = TSView_CN;
PetscFunctionReturn(0);
}
PETSC_EXTERN void PETSC_STDCALL tsthetasettheta_(TS ts,PetscReal *theta, int *__ierr ) {
*__ierr = TSThetaSetTheta(
(TS)PetscToPointer((ts) ),*theta);
}
int main(int argc,char **argv)
{
TS ts; /* nonlinear solver */
Vec u; /* solution, residual vectors */
Mat J; /* Jacobian matrix */
PetscInt steps,maxsteps = 1000; /* iterations for convergence */
PetscErrorCode ierr;
DM da;
MatFDColoring matfdcoloring = PETSC_NULL;
PetscReal ftime,dt;
MonitorCtx usermonitor; /* user-defined monitor context */
AppCtx user; /* user-defined work context */
JacobianType jacType;
PetscInitialize(&argc,&argv,(char *)0,help);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Create distributed array (DMDA) to manage parallel grid and vectors
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = DMDACreate1d(PETSC_COMM_WORLD,DMDA_BOUNDARY_NONE,-11,1,1,PETSC_NULL,&da);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Extract global vectors from DMDA;
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = DMCreateGlobalVector(da,&u);CHKERRQ(ierr);
/* Initialize user application context */
user.c = -30.0;
user.boundary = 0; /* 0: Dirichlet BC; 1: Neumann BC */
user.viewJacobian = PETSC_FALSE;
ierr = PetscOptionsGetInt(PETSC_NULL,"-boundary",&user.boundary,PETSC_NULL);CHKERRQ(ierr);
ierr = PetscOptionsHasName(PETSC_NULL,"-viewJacobian",&user.viewJacobian);CHKERRQ(ierr);
usermonitor.drawcontours = PETSC_FALSE;
ierr = PetscOptionsHasName(PETSC_NULL,"-drawcontours",&usermonitor.drawcontours);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Create timestepping solver context
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = TSCreate(PETSC_COMM_WORLD,&ts);CHKERRQ(ierr);
ierr = TSSetProblemType(ts,TS_NONLINEAR);CHKERRQ(ierr);
ierr = TSSetType(ts,TSTHETA);CHKERRQ(ierr);
ierr = TSThetaSetTheta(ts,1.0);CHKERRQ(ierr); /* Make the Theta method behave like backward Euler */
ierr = TSSetIFunction(ts,PETSC_NULL,FormIFunction,&user);CHKERRQ(ierr);
ierr = DMCreateMatrix(da,MATAIJ,&J);CHKERRQ(ierr);
jacType = JACOBIAN_ANALYTIC; /* use user-provide Jacobian */
ierr = TSSetIJacobian(ts,J,J,FormIJacobian,&user);CHKERRQ(ierr);
ierr = TSSetDM(ts,da);CHKERRQ(ierr); /* Use TSGetDM() to access. Setting here allows easy use of geometric multigrid. */
ftime = 1.0;
ierr = TSSetDuration(ts,maxsteps,ftime);CHKERRQ(ierr);
ierr = TSMonitorSet(ts,MyTSMonitor,&usermonitor,PETSC_NULL);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Set initial conditions
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = FormInitialSolution(ts,u,&user);CHKERRQ(ierr);
ierr = TSSetSolution(ts,u);CHKERRQ(ierr);
dt = .01;
ierr = TSSetInitialTimeStep(ts,0.0,dt);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Set runtime options
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = TSSetFromOptions(ts);CHKERRQ(ierr);
/* Use slow fd Jacobian or fast fd Jacobian with colorings.
Note: this requirs snes which is not created until TSSetUp()/TSSetFromOptions() is called */
ierr = PetscOptionsBegin(((PetscObject)da)->comm,PETSC_NULL,"Options for Jacobian evaluation",PETSC_NULL);CHKERRQ(ierr);
ierr = PetscOptionsEnum("-jac_type","Type of Jacobian","",JacobianTypes,(PetscEnum)jacType,(PetscEnum*)&jacType,0);CHKERRQ(ierr);
ierr = PetscOptionsEnd();CHKERRQ(ierr);
if (jacType == JACOBIAN_FD_COLORING) {
SNES snes;
ISColoring iscoloring;
ierr = DMCreateColoring(da,IS_COLORING_GLOBAL,MATAIJ,&iscoloring);CHKERRQ(ierr);
ierr = MatFDColoringCreate(J,iscoloring,&matfdcoloring);CHKERRQ(ierr);
ierr = MatFDColoringSetFromOptions(matfdcoloring);CHKERRQ(ierr);
ierr = ISColoringDestroy(&iscoloring);CHKERRQ(ierr);
ierr = MatFDColoringSetFunction(matfdcoloring,(PetscErrorCode(*)(void))SNESTSFormFunction,ts);CHKERRQ(ierr);
ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
ierr = SNESSetJacobian(snes,J,J,SNESDefaultComputeJacobianColor,matfdcoloring);CHKERRQ(ierr);
} else if (jacType == JACOBIAN_FD_FULL){
SNES snes;
ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
ierr = SNESSetJacobian(snes,J,J,SNESDefaultComputeJacobian,&user);CHKERRQ(ierr);
}
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Solve nonlinear system
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = TSSolve(ts,u,&ftime);CHKERRQ(ierr);
ierr = TSGetTimeStepNumber(ts,&steps);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Free work space.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = MatDestroy(&J);CHKERRQ(ierr);
if (matfdcoloring) {ierr = MatFDColoringDestroy(&matfdcoloring);CHKERRQ(ierr);}
ierr = VecDestroy(&u);CHKERRQ(ierr);
ierr = TSDestroy(&ts);CHKERRQ(ierr);
ierr = DMDestroy(&da);CHKERRQ(ierr);
ierr = PetscFinalize();
PetscFunctionReturn(0);
}
int main(int argc,char **argv)
{
TS ts; /* nonlinear solver */
Vec u; /* solution, residual vectors */
Mat J; /* Jacobian matrix */
PetscInt maxsteps = 1000; /* iterations for convergence */
PetscInt nsteps;
PetscReal vmin,vmax,norm;
PetscErrorCode ierr;
DM da;
PetscReal ftime,dt;
AppCtx user; /* user-defined work context */
JacobianType jacType;
PetscInitialize(&argc,&argv,(char*)0,help);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Create distributed array (DMDA) to manage parallel grid and vectors
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = DMDACreate1d(PETSC_COMM_WORLD,DMDA_BOUNDARY_NONE,-11,1,1,NULL,&da);
CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Extract global vectors from DMDA;
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = DMCreateGlobalVector(da,&u);
CHKERRQ(ierr);
/* Initialize user application context */
user.c = -30.0;
user.boundary = 0; /* 0: Dirichlet BC; 1: Neumann BC */
user.viewJacobian = PETSC_FALSE;
ierr = PetscOptionsGetInt(NULL,"-boundary",&user.boundary,NULL);
CHKERRQ(ierr);
ierr = PetscOptionsHasName(NULL,"-viewJacobian",&user.viewJacobian);
CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Create timestepping solver context
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = TSCreate(PETSC_COMM_WORLD,&ts);
CHKERRQ(ierr);
ierr = TSSetProblemType(ts,TS_NONLINEAR);
CHKERRQ(ierr);
ierr = TSSetType(ts,TSTHETA);
CHKERRQ(ierr);
ierr = TSThetaSetTheta(ts,1.0);
CHKERRQ(ierr); /* Make the Theta method behave like backward Euler */
ierr = TSSetIFunction(ts,NULL,FormIFunction,&user);
CHKERRQ(ierr);
ierr = DMSetMatType(da,MATAIJ);
CHKERRQ(ierr);
ierr = DMCreateMatrix(da,&J);
CHKERRQ(ierr);
jacType = JACOBIAN_ANALYTIC; /* use user-provide Jacobian */
ierr = TSSetDM(ts,da);
CHKERRQ(ierr); /* Use TSGetDM() to access. Setting here allows easy use of geometric multigrid. */
ftime = 1.0;
ierr = TSSetDuration(ts,maxsteps,ftime);
CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Set initial conditions
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = FormInitialSolution(ts,u,&user);
CHKERRQ(ierr);
ierr = TSSetSolution(ts,u);
CHKERRQ(ierr);
dt = .01;
ierr = TSSetInitialTimeStep(ts,0.0,dt);
CHKERRQ(ierr);
/* Use slow fd Jacobian or fast fd Jacobian with colorings.
Note: this requirs snes which is not created until TSSetUp()/TSSetFromOptions() is called */
ierr = PetscOptionsBegin(PETSC_COMM_WORLD,NULL,"Options for Jacobian evaluation",NULL);
CHKERRQ(ierr);
ierr = PetscOptionsEnum("-jac_type","Type of Jacobian","",JacobianTypes,(PetscEnum)jacType,(PetscEnum*)&jacType,0);
CHKERRQ(ierr);
ierr = PetscOptionsEnd();
CHKERRQ(ierr);
if (jacType == JACOBIAN_ANALYTIC) {
ierr = TSSetIJacobian(ts,J,J,FormIJacobian,&user);
CHKERRQ(ierr);
} else if (jacType == JACOBIAN_FD_COLORING) {
SNES snes;
ierr = TSGetSNES(ts,&snes);
CHKERRQ(ierr);
ierr = SNESSetJacobian(snes,J,J,SNESComputeJacobianDefaultColor,0);
CHKERRQ(ierr);
} else if (jacType == JACOBIAN_FD_FULL) {
SNES snes;
ierr = TSGetSNES(ts,&snes);
CHKERRQ(ierr);
ierr = SNESSetJacobian(snes,J,J,SNESComputeJacobianDefault,&user);
CHKERRQ(ierr);
}
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Set runtime options
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = TSSetFromOptions(ts);
CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Integrate ODE system
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = TSSolve(ts,u);
CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Compute diagnostics of the solution
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = VecNorm(u,NORM_1,&norm);
CHKERRQ(ierr);
ierr = VecMax(u,NULL,&vmax);
CHKERRQ(ierr);
ierr = VecMin(u,NULL,&vmin);
CHKERRQ(ierr);
ierr = TSGetTimeStepNumber(ts,&nsteps);
CHKERRQ(ierr);
ierr = TSGetTime(ts,&ftime);
CHKERRQ(ierr);
ierr = PetscPrintf(PETSC_COMM_WORLD,"timestep %D: time %G, solution norm %G, max %G, min %G\n",nsteps,ftime,norm,vmax,vmin);
CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Free work space.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = MatDestroy(&J);
CHKERRQ(ierr);
ierr = VecDestroy(&u);
CHKERRQ(ierr);
ierr = TSDestroy(&ts);
CHKERRQ(ierr);
ierr = DMDestroy(&da);
CHKERRQ(ierr);
ierr = PetscFinalize();
PetscFunctionReturn(0);
}
