int main(int argc,char **argv)
{
TS ts; /* ODE integrator */
Vec U; /* solution will be stored here */
Mat A; /* Jacobian matrix */
PetscErrorCode ierr;
PetscMPIInt size;
PetscInt n = 3;
AppCtx ctx;
PetscScalar *u;
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Initialize program
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = PetscInitialize(&argc,&argv,(char*)0,help);CHKERRQ(ierr);
ierr = MPI_Comm_size(PETSC_COMM_WORLD,&size);CHKERRQ(ierr);
if (size > 1) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP,"Only for sequential runs");
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Create necessary matrix and vectors
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = MatCreate(PETSC_COMM_WORLD,&A);CHKERRQ(ierr);
ierr = MatSetSizes(A,n,n,PETSC_DETERMINE,PETSC_DETERMINE);CHKERRQ(ierr);
ierr = MatSetFromOptions(A);CHKERRQ(ierr);
ierr = MatSetUp(A);CHKERRQ(ierr);
ierr = MatGetVecs(A,&U,NULL);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Set runtime options
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = PetscOptionsBegin(PETSC_COMM_WORLD,NULL,"Reaction options","");CHKERRQ(ierr);
{
ctx.k = .9;
ierr = PetscOptionsScalar("-k","Reaction coefficient","",ctx.k,&ctx.k,NULL);CHKERRQ(ierr);
ierr = VecDuplicate(U,&ctx.initialsolution);CHKERRQ(ierr);
ierr = VecGetArray(ctx.initialsolution,&u);CHKERRQ(ierr);
u[0] = 1;
u[1] = .7;
u[2] = 0;
ierr = VecRestoreArray(ctx.initialsolution,&u);CHKERRQ(ierr);
ierr = PetscOptionsVec("-initial","Initial values","",ctx.initialsolution,NULL);CHKERRQ(ierr);
}
ierr = PetscOptionsEnd();CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Create timestepping solver context
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = TSCreate(PETSC_COMM_WORLD,&ts);CHKERRQ(ierr);
ierr = TSSetProblemType(ts,TS_NONLINEAR);CHKERRQ(ierr);
ierr = TSSetType(ts,TSROSW);CHKERRQ(ierr);
ierr = TSSetIFunction(ts,NULL,(TSIFunction) IFunction,&ctx);CHKERRQ(ierr);
ierr = TSSetIJacobian(ts,A,A,(TSIJacobian)IJacobian,&ctx);CHKERRQ(ierr);
ierr = TSSetSolutionFunction(ts,(TSSolutionFunction)Solution,&ctx);CHKERRQ(ierr);
{
DM dm;
void *ptr;
ierr = TSGetDM(ts,&dm);CHKERRQ(ierr);
ierr = PetscDLSym(NULL,"IFunctionView",&ptr);CHKERRQ(ierr);
ierr = PetscDLSym(NULL,"IFunctionLoad",&ptr);CHKERRQ(ierr);
ierr = DMTSSetIFunctionSerialize(dm,(PetscErrorCode (*)(void*,PetscViewer))IFunctionView,(PetscErrorCode (*)(void**,PetscViewer))IFunctionLoad);CHKERRQ(ierr);
ierr = DMTSSetIJacobianSerialize(dm,(PetscErrorCode (*)(void*,PetscViewer))IFunctionView,(PetscErrorCode (*)(void**,PetscViewer))IFunctionLoad);CHKERRQ(ierr);
}
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Set initial conditions
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = Solution(ts,0,U,&ctx);CHKERRQ(ierr);
ierr = TSSetSolution(ts,U);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Set solver options
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = TSSetDuration(ts,1000,20.0);CHKERRQ(ierr);
ierr = TSSetInitialTimeStep(ts,0.0,.001);CHKERRQ(ierr);
ierr = TSSetFromOptions(ts);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Solve nonlinear system
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = TSSolve(ts,U);CHKERRQ(ierr);
ierr = TSView(ts,PETSC_VIEWER_BINARY_WORLD);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Free work space. All PETSc objects should be destroyed when they are no longer needed.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = VecDestroy(&ctx.initialsolution);CHKERRQ(ierr);
ierr = MatDestroy(&A);CHKERRQ(ierr);
ierr = VecDestroy(&U);CHKERRQ(ierr);
ierr = TSDestroy(&ts);CHKERRQ(ierr);
ierr = PetscFinalize();
return(0);
}
int main(int argc,char **argv)
{
AppCtx appctx; /* user-defined application context */
PetscErrorCode ierr;
PetscInt i, xs, xm, ind, j, lenglob;
PetscReal x, *wrk_ptr1, *wrk_ptr2;
MatNullSpace nsp;
PetscMPIInt size;
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Initialize program and set problem parameters
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
PetscFunctionBegin;
ierr = PetscInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
/*initialize parameters */
appctx.param.N = 10; /* order of the spectral element */
appctx.param.E = 10; /* number of elements */
appctx.param.L = 4.0; /* length of the domain */
appctx.param.mu = 0.01; /* diffusion coefficient */
appctx.initial_dt = 5e-3;
appctx.param.steps = PETSC_MAX_INT;
appctx.param.Tend = 4;
ierr = PetscOptionsGetInt(NULL,NULL,"-N",&appctx.param.N,NULL);CHKERRQ(ierr);
ierr = PetscOptionsGetInt(NULL,NULL,"-E",&appctx.param.E,NULL);CHKERRQ(ierr);
ierr = PetscOptionsGetReal(NULL,NULL,"-Tend",&appctx.param.Tend,NULL);CHKERRQ(ierr);
ierr = PetscOptionsGetReal(NULL,NULL,"-mu",&appctx.param.mu,NULL);CHKERRQ(ierr);
appctx.param.Le = appctx.param.L/appctx.param.E;
ierr = MPI_Comm_size(PETSC_COMM_WORLD,&size);CHKERRQ(ierr);
if (appctx.param.E % size) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_ARG_WRONG,"Number of elements must be divisible by number of processes");
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Create GLL data structures
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = PetscGLLCreate(appctx.param.N,PETSCGLL_VIA_LINEARALGEBRA,&appctx.SEMop.gll);CHKERRQ(ierr);
lenglob = appctx.param.E*(appctx.param.N-1);
/*
Create distributed array (DMDA) to manage parallel grid and vectors
and to set up the ghost point communication pattern. There are E*(Nl-1)+1
total grid values spread equally among all the processors, except first and last
*/
ierr = DMDACreate1d(PETSC_COMM_WORLD,DM_BOUNDARY_PERIODIC,lenglob,1,1,NULL,&appctx.da);CHKERRQ(ierr);
ierr = DMSetFromOptions(appctx.da);CHKERRQ(ierr);
ierr = DMSetUp(appctx.da);CHKERRQ(ierr);
/*
Extract global and local vectors from DMDA; we use these to store the
approximate solution. Then duplicate these for remaining vectors that
have the same types.
*/
ierr = DMCreateGlobalVector(appctx.da,&appctx.dat.curr_sol);CHKERRQ(ierr);
ierr = VecDuplicate(appctx.dat.curr_sol,&appctx.SEMop.grid);CHKERRQ(ierr);
ierr = VecDuplicate(appctx.dat.curr_sol,&appctx.SEMop.mass);CHKERRQ(ierr);
ierr = DMDAGetCorners(appctx.da,&xs,NULL,NULL,&xm,NULL,NULL);CHKERRQ(ierr);
ierr = DMDAVecGetArray(appctx.da,appctx.SEMop.grid,&wrk_ptr1);CHKERRQ(ierr);
ierr = DMDAVecGetArray(appctx.da,appctx.SEMop.mass,&wrk_ptr2);CHKERRQ(ierr);
/* Compute function over the locally owned part of the grid */
xs=xs/(appctx.param.N-1);
xm=xm/(appctx.param.N-1);
/*
Build total grid and mass over entire mesh (multi-elemental)
*/
for (i=xs; i<xs+xm; i++) {
for (j=0; j<appctx.param.N-1; j++) {
x = (appctx.param.Le/2.0)*(appctx.SEMop.gll.nodes[j]+1.0)+appctx.param.Le*i;
ind=i*(appctx.param.N-1)+j;
wrk_ptr1[ind]=x;
wrk_ptr2[ind]=.5*appctx.param.Le*appctx.SEMop.gll.weights[j];
if (j==0) wrk_ptr2[ind]+=.5*appctx.param.Le*appctx.SEMop.gll.weights[j];
}
}
ierr = DMDAVecRestoreArray(appctx.da,appctx.SEMop.grid,&wrk_ptr1);CHKERRQ(ierr);
ierr = DMDAVecRestoreArray(appctx.da,appctx.SEMop.mass,&wrk_ptr2);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Create matrix data structure; set matrix evaluation routine.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = DMSetMatrixPreallocateOnly(appctx.da, PETSC_TRUE);CHKERRQ(ierr);
ierr = DMCreateMatrix(appctx.da,&appctx.SEMop.stiff);CHKERRQ(ierr);
ierr = DMCreateMatrix(appctx.da,&appctx.SEMop.grad);CHKERRQ(ierr);
/*
For linear problems with a time-dependent f(u,t) in the equation
u_t = f(u,t), the user provides the discretized right-hand-side
as a time-dependent matrix.
*/
ierr = RHSMatrixLaplaciangllDM(appctx.ts,0.0,appctx.dat.curr_sol,appctx.SEMop.stiff,appctx.SEMop.stiff,&appctx);CHKERRQ(ierr);
ierr = RHSMatrixAdvectiongllDM(appctx.ts,0.0,appctx.dat.curr_sol,appctx.SEMop.grad,appctx.SEMop.grad,&appctx);CHKERRQ(ierr);
/*
For linear problems with a time-dependent f(u,t) in the equation
u_t = f(u,t), the user provides the discretized right-hand-side
as a time-dependent matrix.
*/
ierr = MatDuplicate(appctx.SEMop.stiff,MAT_COPY_VALUES,&appctx.SEMop.keptstiff);CHKERRQ(ierr);
/* attach the null space to the matrix, this probably is not needed but does no harm */
ierr = MatNullSpaceCreate(PETSC_COMM_WORLD,PETSC_TRUE,0,NULL,&nsp);CHKERRQ(ierr);
ierr = MatSetNullSpace(appctx.SEMop.stiff,nsp);CHKERRQ(ierr);
ierr = MatSetNullSpace(appctx.SEMop.keptstiff,nsp);CHKERRQ(ierr);
ierr = MatNullSpaceTest(nsp,appctx.SEMop.stiff,NULL);CHKERRQ(ierr);
ierr = MatNullSpaceDestroy(&nsp);CHKERRQ(ierr);
/* attach the null space to the matrix, this probably is not needed but does no harm */
ierr = MatNullSpaceCreate(PETSC_COMM_WORLD,PETSC_TRUE,0,NULL,&nsp);CHKERRQ(ierr);
ierr = MatSetNullSpace(appctx.SEMop.grad,nsp);CHKERRQ(ierr);
ierr = MatNullSpaceTest(nsp,appctx.SEMop.grad,NULL);CHKERRQ(ierr);
ierr = MatNullSpaceDestroy(&nsp);CHKERRQ(ierr);
/* Create the TS solver that solves the ODE and its adjoint; set its options */
ierr = TSCreate(PETSC_COMM_WORLD,&appctx.ts);CHKERRQ(ierr);
ierr = TSSetProblemType(appctx.ts,TS_NONLINEAR);CHKERRQ(ierr);
ierr = TSSetType(appctx.ts,TSRK);CHKERRQ(ierr);
ierr = TSSetDM(appctx.ts,appctx.da);CHKERRQ(ierr);
ierr = TSSetTime(appctx.ts,0.0);CHKERRQ(ierr);
ierr = TSSetTimeStep(appctx.ts,appctx.initial_dt);CHKERRQ(ierr);
ierr = TSSetMaxSteps(appctx.ts,appctx.param.steps);CHKERRQ(ierr);
ierr = TSSetMaxTime(appctx.ts,appctx.param.Tend);CHKERRQ(ierr);
ierr = TSSetExactFinalTime(appctx.ts,TS_EXACTFINALTIME_MATCHSTEP);CHKERRQ(ierr);
ierr = TSSetTolerances(appctx.ts,1e-7,NULL,1e-7,NULL);CHKERRQ(ierr);
ierr = TSSetSaveTrajectory(appctx.ts);CHKERRQ(ierr);
ierr = TSSetFromOptions(appctx.ts);CHKERRQ(ierr);
ierr = TSSetRHSFunction(appctx.ts,NULL,RHSFunction,&appctx);CHKERRQ(ierr);
ierr = TSSetRHSJacobian(appctx.ts,appctx.SEMop.stiff,appctx.SEMop.stiff,RHSJacobian,&appctx);CHKERRQ(ierr);
/* Set Initial conditions for the problem */
ierr = TrueSolution(appctx.ts,0,appctx.dat.curr_sol,&appctx);CHKERRQ(ierr);
ierr = TSSetSolutionFunction(appctx.ts,(PetscErrorCode (*)(TS,PetscReal,Vec,void *))TrueSolution,&appctx);CHKERRQ(ierr);
ierr = TSSetTime(appctx.ts,0.0);CHKERRQ(ierr);
ierr = TSSetStepNumber(appctx.ts,0);CHKERRQ(ierr);
ierr = TSSolve(appctx.ts,appctx.dat.curr_sol);CHKERRQ(ierr);
ierr = MatDestroy(&appctx.SEMop.stiff);CHKERRQ(ierr);
ierr = MatDestroy(&appctx.SEMop.keptstiff);CHKERRQ(ierr);
ierr = MatDestroy(&appctx.SEMop.grad);CHKERRQ(ierr);
ierr = VecDestroy(&appctx.SEMop.grid);CHKERRQ(ierr);
ierr = VecDestroy(&appctx.SEMop.mass);CHKERRQ(ierr);
ierr = VecDestroy(&appctx.dat.curr_sol);CHKERRQ(ierr);
ierr = PetscGLLDestroy(&appctx.SEMop.gll);CHKERRQ(ierr);
ierr = DMDestroy(&appctx.da);CHKERRQ(ierr);
ierr = TSDestroy(&appctx.ts);CHKERRQ(ierr);
/*
Always call PetscFinalize() before exiting a program. This routine
- finalizes the PETSc libraries as well as MPI
- provides summary and diagnostic information if certain runtime
options are chosen (e.g., -log_summary).
*/
ierr = PetscFinalize();
return ierr;
}
int main(int argc,char **argv)
{
AppCtx appctx; /* user-defined application context */
TS ts; /* timestepping context */
Vec U; /* approximate solution vector */
PetscErrorCode ierr;
PetscReal dt;
DM da;
PetscInt M;
PetscMPIInt rank;
PetscBool useLaxWendroff = PETSC_TRUE;
/* Initialize program and set problem parameters */
ierr = PetscInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
ierr = MPI_Comm_rank(PETSC_COMM_WORLD,&rank);CHKERRQ(ierr);
appctx.a = -1.0;
ierr = PetscOptionsGetReal(NULL,NULL,"-a",&appctx.a,NULL);CHKERRQ(ierr);
ierr = DMDACreate1d(PETSC_COMM_WORLD,DM_BOUNDARY_PERIODIC, 60, 1, 1,NULL,&da);CHKERRQ(ierr);
ierr = DMSetFromOptions(da);CHKERRQ(ierr);
ierr = DMSetUp(da);CHKERRQ(ierr);
/* Create vector data structures for approximate and exact solutions */
ierr = DMCreateGlobalVector(da,&U);CHKERRQ(ierr);
/* Create timestepping solver context */
ierr = TSCreate(PETSC_COMM_WORLD,&ts);CHKERRQ(ierr);
ierr = TSSetDM(ts,da);CHKERRQ(ierr);
/* Function evaluation */
ierr = PetscOptionsGetBool(NULL,NULL,"-useLaxWendroff",&useLaxWendroff,NULL);CHKERRQ(ierr);
if (useLaxWendroff) {
if (!rank) {
ierr = PetscPrintf(PETSC_COMM_SELF,"... Use Lax-Wendroff finite volume\n");CHKERRQ(ierr);
}
ierr = TSSetIFunction(ts,NULL,IFunction_LaxWendroff,&appctx);CHKERRQ(ierr);
} else {
if (!rank) {
ierr = PetscPrintf(PETSC_COMM_SELF,"... Use Lax-LaxFriedrichs finite difference\n");CHKERRQ(ierr);
}
ierr = TSSetIFunction(ts,NULL,IFunction_LaxFriedrichs,&appctx);CHKERRQ(ierr);
}
/* Customize timestepping solver */
ierr = DMDAGetInfo(da,PETSC_IGNORE,&M,0,0,0,0,0,0,0,0,0,0,0);CHKERRQ(ierr);
dt = 1.0/(PetscAbsReal(appctx.a)*M);
ierr = TSSetTimeStep(ts,dt);CHKERRQ(ierr);
ierr = TSSetMaxSteps(ts,100);CHKERRQ(ierr);
ierr = TSSetMaxTime(ts,100.0);CHKERRQ(ierr);
ierr = TSSetExactFinalTime(ts,TS_EXACTFINALTIME_STEPOVER);CHKERRQ(ierr);
ierr = TSSetType(ts,TSBEULER);CHKERRQ(ierr);
ierr = TSSetFromOptions(ts);CHKERRQ(ierr);
/* Evaluate initial conditions */
ierr = InitialConditions(ts,U,&appctx);CHKERRQ(ierr);
/* For testing accuracy of TS with already known solution, e.g., '-ts_monitor_lg_error' */
ierr = TSSetSolutionFunction(ts,(PetscErrorCode (*)(TS,PetscReal,Vec,void*))Solution,&appctx);CHKERRQ(ierr);
/* Run the timestepping solver */
ierr = TSSolve(ts,U);CHKERRQ(ierr);
/* Free work space */
ierr = TSDestroy(&ts);CHKERRQ(ierr);
ierr = VecDestroy(&U);CHKERRQ(ierr);
ierr = DMDestroy(&da);CHKERRQ(ierr);
ierr = PetscFinalize();
return ierr;
}
int main(int argc,char **argv)
{
AppCtx appctx; /* user-defined application context */
TS ts; /* timestepping context */
Vec U; /* approximate solution vector */
PetscErrorCode ierr;
PetscReal dt;
DM da;
PetscInt M;
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Initialize program and set problem parameters
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = PetscInitialize(&argc,&argv,(char*)0,help);CHKERRQ(ierr);
appctx.a = 1.0;
appctx.d = 0.0;
ierr = PetscOptionsGetScalar(NULL,"-a",&appctx.a,NULL);CHKERRQ(ierr);
ierr = PetscOptionsGetScalar(NULL,"-d",&appctx.d,NULL);CHKERRQ(ierr);
appctx.upwind = PETSC_TRUE;
ierr = PetscOptionsGetBool(NULL,"-upwind",&appctx.upwind,NULL);CHKERRQ(ierr);
ierr = DMDACreate1d(PETSC_COMM_WORLD,DMDA_BOUNDARY_PERIODIC, -60, 1, 1,NULL,&da);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Create vector data structures
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
/*
Create vector data structures for approximate and exact solutions
*/
ierr = DMCreateGlobalVector(da,&U);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Create timestepping solver context
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = TSCreate(PETSC_COMM_WORLD,&ts);CHKERRQ(ierr);
ierr = TSSetDM(ts,da);CHKERRQ(ierr);
/*
For linear problems with a time-dependent f(U,t) in the equation
u_t = f(u,t), the user provides the discretized right-hand-side
as a time-dependent matrix.
*/
ierr = TSSetRHSFunction(ts,NULL,TSComputeRHSFunctionLinear,&appctx);CHKERRQ(ierr);
ierr = TSSetRHSJacobian(ts,NULL,NULL,RHSMatrixHeat,&appctx);CHKERRQ(ierr);
ierr = TSSetSolutionFunction(ts,(PetscErrorCode (*)(TS,PetscReal,Vec,void*))Solution,&appctx);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Customize timestepping solver:
- Set timestepping duration info
Then set runtime options, which can override these defaults.
For example,
-ts_max_steps <maxsteps> -ts_final_time <maxtime>
to override the defaults set by TSSetDuration().
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = DMDAGetInfo(da,PETSC_IGNORE,&M,0,0,0,0,0,0,0,0,0,0,0);CHKERRQ(ierr);
dt = .48/(M*M);
ierr = TSSetInitialTimeStep(ts,0.0,dt);CHKERRQ(ierr);
ierr = TSSetDuration(ts,1000,100.0);CHKERRQ(ierr);
ierr = TSSetType(ts,TSARKIMEX);CHKERRQ(ierr);
ierr = TSSetFromOptions(ts);CHKERRQ(ierr);
/*
Evaluate initial conditions
*/
ierr = InitialConditions(ts,U,&appctx);CHKERRQ(ierr);
/*
Run the timestepping solver
*/
ierr = TSSolve(ts,U);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Free work space. All PETSc objects should be destroyed when they
are no longer needed.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = TSDestroy(&ts);CHKERRQ(ierr);
ierr = VecDestroy(&U);CHKERRQ(ierr);
ierr = DMDestroy(&da);CHKERRQ(ierr);
/*
Always call PetscFinalize() before exiting a program. This routine
- finalizes the PETSc libraries as well as MPI
- provides summary and diagnostic information if certain runtime
options are chosen (e.g., -log_summary).
*/
ierr = PetscFinalize();
return 0;
}
int main(int argc, char *argv[])
{
PetscMPIInt size;
TS ts;
Vec R;
Mat J;
Vec U,V;
PetscScalar *u,*v;
UserParams user = {/*Omega=*/ 1, /*Xi=*/ 0, /*u0=*/ 1, /*,v0=*/ 0};
PetscErrorCode ierr;
ierr = PetscInitialize(&argc,&argv,NULL,help);CHKERRQ(ierr);
ierr = MPI_Comm_size(PETSC_COMM_WORLD,&size);CHKERRQ(ierr);
if (size > 1) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP,"Only for sequential runs");
ierr = PetscOptionsBegin(PETSC_COMM_SELF,"","ex43 options","");CHKERRQ(ierr);
ierr = PetscOptionsReal("-frequency","Natual frequency",__FILE__,user.Omega,&user.Omega,NULL);CHKERRQ(ierr);
ierr = PetscOptionsReal("-damping","Damping coefficient",__FILE__,user.Xi,&user.Xi,NULL);CHKERRQ(ierr);
ierr = PetscOptionsReal("-initial_u","Initial displacement",__FILE__,user.u0,&user.u0,NULL);CHKERRQ(ierr);
ierr = PetscOptionsReal("-initial_v","Initial velocity",__FILE__,user.v0,&user.v0,NULL);CHKERRQ(ierr);
ierr = PetscOptionsEnd();CHKERRQ(ierr);
ierr = TSCreate(PETSC_COMM_SELF,&ts);CHKERRQ(ierr);
ierr = TSSetType(ts,TSALPHA2);CHKERRQ(ierr);
ierr = TSSetMaxTime(ts,5*(2*PETSC_PI));CHKERRQ(ierr);
ierr = TSSetExactFinalTime(ts,TS_EXACTFINALTIME_STEPOVER);CHKERRQ(ierr);
ierr = TSSetTimeStep(ts,0.01);CHKERRQ(ierr);
ierr = VecCreateSeq(PETSC_COMM_SELF,1,&R);CHKERRQ(ierr);
ierr = VecSetUp(R);CHKERRQ(ierr);
ierr = MatCreateSeqDense(PETSC_COMM_SELF,1,1,NULL,&J);CHKERRQ(ierr);
ierr = MatSetUp(J);CHKERRQ(ierr);
if (user.Xi) {
ierr = TSSetI2Function(ts,R,Residual2,&user);CHKERRQ(ierr);
ierr = TSSetI2Jacobian(ts,J,J,Tangent2,&user);CHKERRQ(ierr);
} else {
ierr = TSSetIFunction(ts,R,Residual1,&user);CHKERRQ(ierr);
ierr = TSSetIJacobian(ts,J,J,Tangent1,&user);CHKERRQ(ierr);
}
ierr = VecDestroy(&R);CHKERRQ(ierr);
ierr = MatDestroy(&J);CHKERRQ(ierr);
ierr = TSSetSolutionFunction(ts,Solution,&user);CHKERRQ(ierr);
ierr = VecCreateSeq(PETSC_COMM_SELF,1,&U);CHKERRQ(ierr);
ierr = VecCreateSeq(PETSC_COMM_SELF,1,&V);CHKERRQ(ierr);
ierr = VecGetArray(U,&u);CHKERRQ(ierr);
ierr = VecGetArray(V,&v);CHKERRQ(ierr);
u[0] = user.u0;
v[0] = user.v0;
ierr = VecRestoreArray(U,&u);CHKERRQ(ierr);
ierr = VecRestoreArray(V,&v);CHKERRQ(ierr);
ierr = TS2SetSolution(ts,U,V);CHKERRQ(ierr);
ierr = TSSetFromOptions(ts);CHKERRQ(ierr);
ierr = TSSolve(ts,NULL);CHKERRQ(ierr);
ierr = VecDestroy(&U);CHKERRQ(ierr);
ierr = VecDestroy(&V);CHKERRQ(ierr);
ierr = TSDestroy(&ts);CHKERRQ(ierr);
ierr = PetscFinalize();
return ierr;
}
