void Solve_Distance(UserCtx *user, int iter)
{
SNES snes_distance;
KSP ksp;
PC pc;
Vec r;
Mat J;
double norm;
int bi=0;
VecDuplicate(LevelSet, &r);
SNESCreate(PETSC_COMM_WORLD,&snes_distance);
SNESSetFunction(snes_distance,r,FormFunction_Distance,(void *)&user[bi]);
MatCreateSNESMF(snes_distance, &J);
SNESSetJacobian(snes_distance,J,J,MatMFFDComputeJacobian,(void *)&user[bi]);
SNESSetType(snes_distance, SNESTR); //SNESTR,SNESLS
double tol=1.e-2;
SNESSetMaxLinearSolveFailures(snes_distance,10000);
SNESSetMaxNonlinearStepFailures(snes_distance,10000);
SNESKSPSetUseEW(snes_distance, PETSC_TRUE);
SNESKSPSetParametersEW(snes_distance,3,PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT);
SNESSetTolerances(snes_distance,PETSC_DEFAULT,tol,PETSC_DEFAULT,5,50000); // snes iter
SNESGetKSP(snes_distance, &ksp);
KSPSetType(ksp, KSPGMRES);
//KSPGMRESSetPreAllocateVectors(ksp);
KSPGetPC(ksp,&pc);
PCSetType(pc,PCNONE);
//int maxits=10;
int maxits=4; // ksp iter
double rtol=tol, atol=PETSC_DEFAULT, dtol=PETSC_DEFAULT;
KSPSetTolerances(ksp,rtol,atol,dtol,maxits);
extern PetscErrorCode MySNESMonitor(SNES snes,PetscInt n,PetscReal rnorm,void *dummy);
SNESMonitorSet(snes_distance,MySNESMonitor,PETSC_NULL,PETSC_NULL);
SNESSolve(snes_distance, PETSC_NULL, LevelSet);
SNESGetFunctionNorm(snes_distance, &norm);
//PetscPrintf(PETSC_COMM_WORLD, "\nDistance SNES residual norm=%.5e\n\n", norm);
VecDestroy(r);
MatDestroy(J);
SNESDestroy(snes_distance);
};
int main(int argc,char **argv)
{
AppCtx user; /* user-defined work context */
PetscInt mx,my;
PetscErrorCode ierr;
MPI_Comm comm;
DM da;
Vec x;
Mat J = NULL,Jmf = NULL;
MatShellCtx matshellctx;
PetscInt mlocal,nlocal;
PC pc;
KSP ksp;
PetscBool errorinmatmult = PETSC_FALSE,errorinpcapply = PETSC_FALSE,errorinpcsetup = PETSC_FALSE;
ierr = PetscInitialize(&argc,&argv,(char*)0,help);if (ierr) return(1);
PetscFunctionBeginUser;
ierr = PetscOptionsGetBool(NULL,"-error_in_matmult",&errorinmatmult,NULL);CHKERRQ(ierr);
ierr = PetscOptionsGetBool(NULL,"-error_in_pcapply",&errorinpcapply,NULL);CHKERRQ(ierr);
ierr = PetscOptionsGetBool(NULL,"-error_in_pcsetup",&errorinpcsetup,NULL);CHKERRQ(ierr);
ierr = PetscOptionsGetBool(NULL,"-error_in_domain",&user.errorindomain,NULL);CHKERRQ(ierr);
ierr = PetscOptionsGetBool(NULL,"-error_in_domainmf",&user.errorindomainmf,NULL);CHKERRQ(ierr);
comm = PETSC_COMM_WORLD;
ierr = SNESCreate(comm,&user.snes);CHKERRQ(ierr);
/*
Create distributed array object to manage parallel grid and vectors
for principal unknowns (x) and governing residuals (f)
*/
ierr = DMDACreate2d(PETSC_COMM_WORLD,DM_BOUNDARY_NONE,DM_BOUNDARY_NONE,DMDA_STENCIL_STAR,-4,-4,PETSC_DECIDE,PETSC_DECIDE,4,1,0,0,&da);CHKERRQ(ierr);
ierr = SNESSetDM(user.snes,da);CHKERRQ(ierr);
ierr = DMDAGetInfo(da,0,&mx,&my,PETSC_IGNORE,PETSC_IGNORE,PETSC_IGNORE,PETSC_IGNORE,PETSC_IGNORE,PETSC_IGNORE,
PETSC_IGNORE,PETSC_IGNORE,PETSC_IGNORE,PETSC_IGNORE);CHKERRQ(ierr);
/*
Problem parameters (velocity of lid, prandtl, and grashof numbers)
*/
user.lidvelocity = 1.0/(mx*my);
user.prandtl = 1.0;
user.grashof = 1.0;
ierr = PetscOptionsGetReal(NULL,"-lidvelocity",&user.lidvelocity,NULL);CHKERRQ(ierr);
ierr = PetscOptionsGetReal(NULL,"-prandtl",&user.prandtl,NULL);CHKERRQ(ierr);
ierr = PetscOptionsGetReal(NULL,"-grashof",&user.grashof,NULL);CHKERRQ(ierr);
ierr = PetscOptionsHasName(NULL,"-contours",&user.draw_contours);CHKERRQ(ierr);
ierr = DMDASetFieldName(da,0,"x_velocity");CHKERRQ(ierr);
ierr = DMDASetFieldName(da,1,"y_velocity");CHKERRQ(ierr);
ierr = DMDASetFieldName(da,2,"Omega");CHKERRQ(ierr);
ierr = DMDASetFieldName(da,3,"temperature");CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Create user context, set problem data, create vector data structures.
Also, compute the initial guess.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Create nonlinear solver context
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = DMSetApplicationContext(da,&user);CHKERRQ(ierr);
ierr = DMDASNESSetFunctionLocal(da,INSERT_VALUES,(PetscErrorCode (*)(DMDALocalInfo*,void*,void*,void*))FormFunctionLocal,&user);CHKERRQ(ierr);
if (errorinmatmult) {
ierr = MatCreateSNESMF(user.snes,&Jmf);CHKERRQ(ierr);
ierr = MatSetFromOptions(Jmf);CHKERRQ(ierr);
ierr = MatGetLocalSize(Jmf,&mlocal,&nlocal);CHKERRQ(ierr);
matshellctx.Jmf = Jmf;
ierr = MatCreateShell(PetscObjectComm((PetscObject)Jmf),mlocal,nlocal,PETSC_DECIDE,PETSC_DECIDE,&matshellctx,&J);CHKERRQ(ierr);
ierr = MatShellSetOperation(J,MATOP_MULT,(void (*)(void))MatMult_MyShell);CHKERRQ(ierr);
ierr = MatShellSetOperation(J,MATOP_ASSEMBLY_END,(void (*)(void))MatAssemblyEnd_MyShell);CHKERRQ(ierr);
ierr = SNESSetJacobian(user.snes,J,J,MatMFFDComputeJacobian,NULL);CHKERRQ(ierr);
}
ierr = SNESSetFromOptions(user.snes);CHKERRQ(ierr);
ierr = PetscPrintf(comm,"lid velocity = %g, prandtl # = %g, grashof # = %g\n",(double)user.lidvelocity,(double)user.prandtl,(double)user.grashof);CHKERRQ(ierr);
if (errorinpcapply) {
ierr = SNESGetKSP(user.snes,&ksp);CHKERRQ(ierr);
ierr = KSPGetPC(ksp,&pc);CHKERRQ(ierr);
ierr = PCSetType(pc,PCSHELL);CHKERRQ(ierr);
ierr = PCShellSetApply(pc,PCApply_MyShell);CHKERRQ(ierr);
}
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Solve the nonlinear system
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = DMCreateGlobalVector(da,&x);CHKERRQ(ierr);
ierr = FormInitialGuess(&user,da,x);CHKERRQ(ierr);
if (errorinpcsetup) {
ierr = SNESSetUp(user.snes);CHKERRQ(ierr);
ierr = SNESSetJacobian(user.snes,NULL,NULL,SNESComputeJacobian_MyShell,NULL);CHKERRQ(ierr);
}
ierr = SNESSolve(user.snes,NULL,x);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Free work space. All PETSc objects should be destroyed when they
are no longer needed.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = MatDestroy(&J);CHKERRQ(ierr);
ierr = MatDestroy(&Jmf);CHKERRQ(ierr);
ierr = VecDestroy(&x);CHKERRQ(ierr);
ierr = DMDestroy(&da);CHKERRQ(ierr);
ierr = SNESDestroy(&user.snes);CHKERRQ(ierr);
ierr = PetscFinalize();
return 0;
}
int main(int argc,char **argv)
{
TS ts; /* nonlinear solver */
Vec u,r; /* solution, residual vectors */
Mat J,Jmf = PETSC_NULL; /* Jacobian matrices */
PetscInt maxsteps = 1000; /* iterations for convergence */
PetscErrorCode ierr;
DM da;
PetscReal dt;
AppCtx user; /* user-defined work context */
SNES snes;
PetscInt Jtype; /* Jacobian type
0: user provide Jacobian;
1: slow finite difference;
2: fd with coloring; */
PetscInitialize(&argc,&argv,(char *)0,help);
/* Initialize user application context */
user.da = PETSC_NULL;
user.nstencilpts = 5;
user.c = -30.0;
user.boundary = 0; /* 0: Drichlet BC; 1: Neumann BC */
user.viewJacobian = PETSC_FALSE;
ierr = PetscOptionsGetInt(PETSC_NULL,"-nstencilpts",&user.nstencilpts,PETSC_NULL);CHKERRQ(ierr);
ierr = PetscOptionsGetInt(PETSC_NULL,"-boundary",&user.boundary,PETSC_NULL);CHKERRQ(ierr);
ierr = PetscOptionsHasName(PETSC_NULL,"-viewJacobian",&user.viewJacobian);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Create distributed array (DMDA) to manage parallel grid and vectors
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
if (user.nstencilpts == 5){
ierr = DMDACreate2d(PETSC_COMM_WORLD, DMDA_BOUNDARY_NONE, DMDA_BOUNDARY_NONE,DMDA_STENCIL_STAR,-11,-11,PETSC_DECIDE,PETSC_DECIDE,1,1,PETSC_NULL,PETSC_NULL,&da);CHKERRQ(ierr);
} else if (user.nstencilpts == 9){
ierr = DMDACreate2d(PETSC_COMM_WORLD, DMDA_BOUNDARY_NONE, DMDA_BOUNDARY_NONE,DMDA_STENCIL_BOX,-11,-11,PETSC_DECIDE,PETSC_DECIDE,1,1,PETSC_NULL,PETSC_NULL,&da);CHKERRQ(ierr);
} else {
SETERRQ1(PETSC_COMM_WORLD,PETSC_ERR_SUP,"nstencilpts %d is not supported",user.nstencilpts);
}
user.da = da;
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Extract global vectors from DMDA;
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = DMCreateGlobalVector(da,&u);CHKERRQ(ierr);
ierr = VecDuplicate(u,&r);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Create timestepping solver context
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = TSCreate(PETSC_COMM_WORLD,&ts);CHKERRQ(ierr);
ierr = TSSetProblemType(ts,TS_NONLINEAR);CHKERRQ(ierr);
ierr = TSSetType(ts,TSBEULER);CHKERRQ(ierr);
ierr = TSSetDM(ts,da);CHKERRQ(ierr);
ierr = TSSetIFunction(ts,r,FormIFunction,&user);CHKERRQ(ierr);
ierr = TSSetDuration(ts,maxsteps,1.0);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Set initial conditions
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = FormInitialSolution(u,&user);CHKERRQ(ierr);
ierr = TSSetSolution(ts,u);CHKERRQ(ierr);
dt = .01;
ierr = TSSetInitialTimeStep(ts,0.0,dt);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Set Jacobian evaluation routine
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = DMCreateMatrix(da,MATAIJ,&J);CHKERRQ(ierr);
Jtype = 0;
ierr = PetscOptionsGetInt(PETSC_NULL, "-Jtype",&Jtype,PETSC_NULL);CHKERRQ(ierr);
if (Jtype == 0){ /* use user provided Jacobian evaluation routine */
if (user.nstencilpts != 5) SETERRQ1(PETSC_COMM_WORLD,PETSC_ERR_SUP,"user Jacobian routine FormIJacobian() does not support nstencilpts=%D",user.nstencilpts);
ierr = TSSetIJacobian(ts,J,J,FormIJacobian,&user);CHKERRQ(ierr);
} else { /* use finite difference Jacobian J as preconditioner and '-snes_mf_operator' for Mat*vec */
ierr = TSGetSNES(ts,&snes);CHKERRQ(ierr);
ierr = MatCreateSNESMF(snes,&Jmf);CHKERRQ(ierr);
if (Jtype == 1){ /* slow finite difference J; */
ierr = SNESSetJacobian(snes,Jmf,J,SNESDefaultComputeJacobian,PETSC_NULL);CHKERRQ(ierr);
} else if (Jtype == 2){ /* Use coloring to compute finite difference J efficiently */
ierr = SNESSetJacobian(snes,Jmf,J,SNESDefaultComputeJacobianColor,0);CHKERRQ(ierr);
} else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Jtype is not supported");
}
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Sets various TS parameters from user options
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = TSSetFromOptions(ts);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Solve nonlinear system
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = TSSolve(ts,u);CHKERRQ(ierr);
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Free work space.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
ierr = MatDestroy(&J);CHKERRQ(ierr);
ierr = MatDestroy(&Jmf);CHKERRQ(ierr);
ierr = VecDestroy(&u);CHKERRQ(ierr);
ierr = VecDestroy(&r);CHKERRQ(ierr);
ierr = TSDestroy(&ts);CHKERRQ(ierr);
ierr = DMDestroy(&da);CHKERRQ(ierr);
ierr = PetscFinalize();
PetscFunctionReturn(0);
}