C++ PetscViewerASCIISubtractTab函数代码示例

/*@C
   KSPMonitorRange - Prints the percentage of residual elements that are more then 10 percent of the maximum value.

   Collective on KSP

   Input Parameters:
+  ksp   - iterative context
.  it    - iteration number
.  rnorm - 2-norm (preconditioned) residual value (may be estimated).
-  dummy - an ASCII viewer

   Options Database Key:
.  -ksp_monitor_range - Activates KSPMonitorRange()

   Level: intermediate

.keywords: KSP, default, monitor, residual

.seealso: KSPMonitorSet(), KSPMonitorDefault(), KSPMonitorLGResidualNormCreate()
@*/
PetscErrorCode  KSPMonitorRange(KSP ksp,PetscInt it,PetscReal rnorm,PetscViewerAndFormat *dummy)
{
    PetscErrorCode   ierr;
    PetscReal        perc,rel;
    PetscViewer      viewer = dummy->viewer;
    /* should be in a MonitorRangeContext */
    static PetscReal prev;

    PetscFunctionBegin;
    PetscValidHeaderSpecific(viewer,PETSC_VIEWER_CLASSID,4);
    ierr = PetscViewerPushFormat(viewer,dummy->format);
    CHKERRQ(ierr);
    ierr = PetscViewerASCIIAddTab(viewer,((PetscObject)ksp)->tablevel);
    CHKERRQ(ierr);
    if (!it) prev = rnorm;
    if (it == 0 && ((PetscObject)ksp)->prefix) {
        ierr = PetscViewerASCIIPrintf(viewer,"  Residual norms for %s solve.\n",((PetscObject)ksp)->prefix);
        CHKERRQ(ierr);
    }
    ierr = KSPMonitorRange_Private(ksp,it,&perc);
    CHKERRQ(ierr);

    rel  = (prev - rnorm)/prev;
    prev = rnorm;
    ierr = PetscViewerASCIIPrintf(viewer,"%3D KSP preconditioned resid norm %14.12e Percent values above 20 percent of maximum %5.2f relative decrease %5.2e ratio %5.2e \n",it,(double)rnorm,(double)(100.0*perc),(double)rel,(double)(rel/perc));
    CHKERRQ(ierr);
    ierr = PetscViewerASCIISubtractTab(viewer,((PetscObject)ksp)->tablevel);
    CHKERRQ(ierr);
    ierr = PetscViewerPopFormat(viewer);
    CHKERRQ(ierr);
    PetscFunctionReturn(0);
}

/*@C
   KSPMonitorTrueResidualMaxNorm - Prints the true residual max norm as well as the preconditioned
   residual norm at each iteration of an iterative solver.

   Collective on KSP

   Input Parameters:
+  ksp   - iterative context
.  n     - iteration number
.  rnorm - norm (preconditioned) residual value (may be estimated).
-  dummy - an ASCII viewer

   Options Database Key:
.  -ksp_monitor_max - Activates KSPMonitorTrueResidualMaxNorm()

   Notes:
   This could be implemented (better) with a flag in ksp.

   Level: intermediate

.keywords: KSP, default, monitor, residual

.seealso: KSPMonitorSet(), KSPMonitorDefault(), KSPMonitorLGResidualNormCreate(),KSPMonitorTrueResidualNorm()
@*/
PetscErrorCode  KSPMonitorTrueResidualMaxNorm(KSP ksp,PetscInt n,PetscReal rnorm,void *dummy)
{
  PetscErrorCode ierr;
  Vec            resid;
  PetscReal      truenorm,bnorm;
  PetscViewer    viewer = (PetscViewer)dummy;
  char           normtype[256];

  PetscFunctionBegin;
  PetscValidHeaderSpecific(viewer,PETSC_VIEWER_CLASSID,4);
  ierr = PetscViewerASCIIAddTab(viewer,((PetscObject)ksp)->tablevel);CHKERRQ(ierr);
  if (n == 0 && ((PetscObject)ksp)->prefix) {
    ierr = PetscViewerASCIIPrintf(viewer,"  Residual norms (max) for %s solve.\n",((PetscObject)ksp)->prefix);CHKERRQ(ierr);
  }
  ierr = KSPBuildResidual(ksp,NULL,NULL,&resid);CHKERRQ(ierr);
  ierr = VecNorm(resid,NORM_INFINITY,&truenorm);CHKERRQ(ierr);
  ierr = VecDestroy(&resid);CHKERRQ(ierr);
  ierr = VecNorm(ksp->vec_rhs,NORM_INFINITY,&bnorm);CHKERRQ(ierr);
  ierr = PetscStrncpy(normtype,KSPNormTypes[ksp->normtype],sizeof(normtype));CHKERRQ(ierr);
  ierr = PetscStrtolower(normtype);CHKERRQ(ierr);
  /* ierr = PetscViewerASCIIPrintf(viewer,"%3D KSP %s resid norm %14.12e true resid norm %14.12e ||r(i)||_inf/||b||_inf %14.12e\n",n,normtype,(double)rnorm,(double)truenorm,(double)(truenorm/bnorm));CHKERRQ(ierr); */
  ierr = PetscViewerASCIIPrintf(viewer,"%3D KSP true resid max norm %14.12e ||r(i)||/||b|| %14.12e\n",n,(double)truenorm,(double)(truenorm/bnorm));CHKERRQ(ierr);
  ierr = PetscViewerASCIISubtractTab(viewer,((PetscObject)ksp)->tablevel);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}

/*@C
   KSPMonitorSNES - Print the residual norm of the nonlinear function at each iteration of the linear iterative solver.

   Collective on KSP

   Input Parameters:
+  ksp   - iterative context
.  n     - iteration number
.  rnorm - 2-norm (preconditioned) residual value (may be estimated).
-  dummy - unused monitor context

   Level: intermediate

.keywords: KSP, default, monitor, residual

.seealso: KSPMonitorSet(), KSPMonitorTrueResidualNorm(), KSPMonitorLGResidualNormCreate()
@*/
PetscErrorCode  KSPMonitorSNES(KSP ksp,PetscInt n,PetscReal rnorm,void *dummy)
{
  PetscErrorCode ierr;
  PetscViewer    viewer;
  SNES           snes = (SNES) dummy;
  Vec            snes_solution,work1,work2;
  PetscReal      snorm;

  PetscFunctionBegin;
  ierr = SNESGetSolution(snes,&snes_solution);CHKERRQ(ierr);
  ierr = VecDuplicate(snes_solution,&work1);CHKERRQ(ierr);
  ierr = VecDuplicate(snes_solution,&work2);CHKERRQ(ierr);
  ierr = KSPBuildSolution(ksp,work1,NULL);CHKERRQ(ierr);
  ierr = VecAYPX(work1,-1.0,snes_solution);CHKERRQ(ierr);
  ierr = SNESComputeFunction(snes,work1,work2);CHKERRQ(ierr);
  ierr = VecNorm(work2,NORM_2,&snorm);CHKERRQ(ierr);
  ierr = VecDestroy(&work1);CHKERRQ(ierr);
  ierr = VecDestroy(&work2);CHKERRQ(ierr);

  ierr = PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)ksp),&viewer);CHKERRQ(ierr);
  ierr = PetscViewerASCIIAddTab(viewer,((PetscObject)ksp)->tablevel);CHKERRQ(ierr);
  if (n == 0 && ((PetscObject)ksp)->prefix) {
    ierr = PetscViewerASCIIPrintf(viewer,"  Residual norms for %s solve.\n",((PetscObject)ksp)->prefix);CHKERRQ(ierr);
  }
  ierr = PetscViewerASCIIPrintf(viewer,"%3D SNES Residual norm %5.3e KSP Residual norm %5.3e \n",n,(double)snorm,(double)rnorm);CHKERRQ(ierr);
  ierr = PetscViewerASCIISubtractTab(viewer,((PetscObject)ksp)->tablevel);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}

/*@
  PetscConvEstRateView - Displays the convergence rate to a viewer

   Collective on SNES

   Parameter:
+  snes - iterative context obtained from SNESCreate()
.  alpha - the convergence rate for each field
-  viewer - the viewer to display the reason

   Options Database Keys:
.  -snes_convergence_estimate - print the convergence rate

   Level: developer

.seealso: PetscConvEstGetRate()
@*/
PetscErrorCode PetscConvEstRateView(PetscConvEst ce, const PetscReal alpha[], PetscViewer viewer)
{
  PetscBool      isAscii;
  PetscErrorCode ierr;

  PetscFunctionBegin;
  ierr = PetscObjectTypeCompare((PetscObject) viewer, PETSCVIEWERASCII, &isAscii);CHKERRQ(ierr);
  if (isAscii) {
    DM       dm;
    PetscInt Nf, f;

    ierr = SNESGetDM(ce->snes, &dm);CHKERRQ(ierr);
    ierr = DMGetNumFields(dm, &Nf);CHKERRQ(ierr);
    ierr = PetscViewerASCIIAddTab(viewer, ((PetscObject) ce)->tablevel);CHKERRQ(ierr);
    ierr = PetscViewerASCIIPrintf(viewer, "L_2 convergence rate: ");CHKERRQ(ierr);
    if (Nf > 1) {ierr = PetscViewerASCIIPrintf(viewer, "[");CHKERRQ(ierr);}
    for (f = 0; f < Nf; ++f) {
      if (f > 0) {ierr = PetscViewerASCIIPrintf(viewer, ", ");CHKERRQ(ierr);}
      ierr = PetscViewerASCIIPrintf(viewer, "%#.2g", (double) alpha[f]);CHKERRQ(ierr);
    }
    if (Nf > 1) {ierr = PetscViewerASCIIPrintf(viewer, "]");CHKERRQ(ierr);}
    ierr = PetscViewerASCIIPrintf(viewer, "\n");CHKERRQ(ierr);
    ierr = PetscViewerASCIISubtractTab(viewer, ((PetscObject) ce)->tablevel);CHKERRQ(ierr);
  }
  PetscFunctionReturn(0);
}

/*@C
   KSPMonitorTrueResidualNorm - Prints the true residual norm as well as the preconditioned
   residual norm at each iteration of an iterative solver.

   Collective on KSP

   Input Parameters:
+  ksp   - iterative context
.  n     - iteration number
.  rnorm - 2-norm (preconditioned) residual value (may be estimated).
-  dummy - unused monitor context

   Options Database Key:
.  -ksp_monitor_true_residual - Activates KSPMonitorTrueResidualNorm()

   Notes:
   When using right preconditioning, these values are equivalent.

   Level: intermediate

.keywords: KSP, default, monitor, residual

.seealso: KSPMonitorSet(), KSPMonitorDefault(), KSPMonitorLGResidualNormCreate(),KSPMonitorTrueResidualMaxNorm()
@*/
PetscErrorCode  KSPMonitorTrueResidualNorm(KSP ksp,PetscInt n,PetscReal rnorm,void *dummy)
{
  PetscErrorCode ierr;
  Vec            resid;
  PetscReal      truenorm,bnorm;
  PetscViewer    viewer = (PetscViewer)dummy;
  char           normtype[256];

  PetscFunctionBegin;
  if (!viewer) {
    ierr = PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)ksp),&viewer);CHKERRQ(ierr);
  }
  ierr = PetscViewerASCIIAddTab(viewer,((PetscObject)ksp)->tablevel);CHKERRQ(ierr);
  if (n == 0 && ((PetscObject)ksp)->prefix) {
    ierr = PetscViewerASCIIPrintf(viewer,"  Residual norms for %s solve.\n",((PetscObject)ksp)->prefix);CHKERRQ(ierr);
  }
  ierr = KSPBuildResidual(ksp,NULL,NULL,&resid);CHKERRQ(ierr);
  ierr = VecNorm(resid,NORM_2,&truenorm);CHKERRQ(ierr);
  ierr = VecDestroy(&resid);CHKERRQ(ierr);
  ierr = VecNorm(ksp->vec_rhs,NORM_2,&bnorm);CHKERRQ(ierr);
  ierr = PetscStrncpy(normtype,KSPNormTypes[ksp->normtype],sizeof(normtype));CHKERRQ(ierr);
  ierr = PetscStrtolower(normtype);CHKERRQ(ierr);
  ierr = PetscViewerASCIIPrintf(viewer,"%3D KSP %s resid norm %14.12e true resid norm %14.12e ||r(i)||/||b|| %14.12e\n",n,normtype,(double)rnorm,(double)truenorm,(double)(truenorm/bnorm));CHKERRQ(ierr);
  ierr = PetscViewerASCIISubtractTab(viewer,((PetscObject)ksp)->tablevel);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}

/*@C
    KSPMonitorSingularValue - Prints the two norm of the true residual and
    estimation of the extreme singular values of the preconditioned problem
    at each iteration.

    Logically Collective on KSP

    Input Parameters:
+   ksp - the iterative context
.   n  - the iteration
-   rnorm - the two norm of the residual

    Options Database Key:
.   -ksp_monitor_singular_value - Activates KSPMonitorSingularValue()

    Notes:
    The CG solver uses the Lanczos technique for eigenvalue computation,
    while GMRES uses the Arnoldi technique; other iterative methods do
    not currently compute singular values.

    Level: intermediate

.keywords: KSP, CG, default, monitor, extreme, singular values, Lanczos, Arnoldi

.seealso: KSPComputeExtremeSingularValues()
@*/
PetscErrorCode  KSPMonitorSingularValue(KSP ksp,PetscInt n,PetscReal rnorm,PetscViewerAndFormat *dummy)
{
    PetscReal      emin,emax,c;
    PetscErrorCode ierr;
    PetscViewer    viewer = dummy->viewer;

    PetscFunctionBegin;
    PetscValidHeaderSpecific(ksp,KSP_CLASSID,1);
    PetscValidHeaderSpecific(viewer,PETSC_VIEWER_CLASSID,4);
    ierr = PetscViewerPushFormat(viewer,dummy->format);
    CHKERRQ(ierr);
    ierr = PetscViewerASCIIAddTab(viewer,((PetscObject)ksp)->tablevel);
    CHKERRQ(ierr);
    if (!ksp->calc_sings) {
        ierr = PetscViewerASCIIPrintf(viewer,"%3D KSP Residual norm %14.12e \n",n,(double)rnorm);
        CHKERRQ(ierr);
    } else {
        ierr = KSPComputeExtremeSingularValues(ksp,&emax,&emin);
        CHKERRQ(ierr);
        c    = emax/emin;
        ierr = PetscViewerASCIIPrintf(viewer,"%3D KSP Residual norm %14.12e %% max %14.12e min %14.12e max/min %14.12e\n",n,(double)rnorm,(double)emax,(double)emin,(double)c);
        CHKERRQ(ierr);
    }
    ierr = PetscViewerASCIISubtractTab(viewer,((PetscObject)ksp)->tablevel);
    CHKERRQ(ierr);
    ierr = PetscViewerPopFormat(viewer);
    CHKERRQ(ierr);
    PetscFunctionReturn(0);
}

/*
  Default (short) KSP Monitor, same as KSPMonitorDefault() except
  it prints fewer digits of the residual as the residual gets smaller.
  This is because the later digits are meaningless and are often
  different on different machines; by using this routine different
  machines will usually generate the same output.
*/
PetscErrorCode  KSPMonitorDefaultShort(KSP ksp,PetscInt its,PetscReal fnorm,PetscViewerAndFormat *dummy)
{
    PetscErrorCode ierr;
    PetscViewer    viewer = dummy->viewer;

    PetscFunctionBegin;
    PetscValidHeaderSpecific(viewer,PETSC_VIEWER_CLASSID,4);
    ierr = PetscViewerPushFormat(viewer,dummy->format);
    CHKERRQ(ierr);
    ierr = PetscViewerASCIIAddTab(viewer,((PetscObject)ksp)->tablevel);
    CHKERRQ(ierr);
    if (its == 0 && ((PetscObject)ksp)->prefix) {
        ierr = PetscViewerASCIIPrintf(viewer,"  Residual norms for %s solve.\n",((PetscObject)ksp)->prefix);
        CHKERRQ(ierr);
    }

    if (fnorm > 1.e-9) {
        ierr = PetscViewerASCIIPrintf(viewer,"%3D KSP Residual norm %g \n",its,(double)fnorm);
        CHKERRQ(ierr);
    } else if (fnorm > 1.e-11) {
        ierr = PetscViewerASCIIPrintf(viewer,"%3D KSP Residual norm %5.3e \n",its,(double)fnorm);
        CHKERRQ(ierr);
    } else {
        ierr = PetscViewerASCIIPrintf(viewer,"%3D KSP Residual norm < 1.e-11\n",its);
        CHKERRQ(ierr);
    }
    ierr = PetscViewerASCIISubtractTab(viewer,((PetscObject)ksp)->tablevel);
    CHKERRQ(ierr);
    ierr = PetscViewerPopFormat(viewer);
    CHKERRQ(ierr);
    PetscFunctionReturn(0);
}

PetscErrorCode SNESQNApply_BadBroyden(SNES snes,PetscInt it,Vec Y,Vec X,Vec Xold,Vec D,Vec Dold)
{
  PetscErrorCode ierr;
  SNES_QN        *qn = (SNES_QN*)snes->data;
  Vec            W   = snes->work[3];
  Vec            *U  = qn->U;
  Vec            *T  = qn->V;

  /* ksp thing for Jacobian scaling */
  PetscInt           h,k,j,i,lits;
  PetscInt           m = qn->m;
  PetscScalar        gdot,udot;
  PetscInt           l = m;

  PetscFunctionBegin;
  if (it < m) l = it;
  ierr = VecCopy(D,Y);CHKERRQ(ierr);
  if (l > 0) {
    k    = (it-1)%l;
    ierr = SNESLineSearchGetLambda(snes->linesearch,&qn->lambda[k]);CHKERRQ(ierr);
    ierr = VecCopy(Dold,U[k]);CHKERRQ(ierr);
    ierr = VecAXPY(U[k],-1.0,D);CHKERRQ(ierr);
    ierr = VecCopy(Xold,T[k]);CHKERRQ(ierr);
    ierr = VecAXPY(T[k],-1.0,X);CHKERRQ(ierr);
  }

  if (qn->scale_type == SNES_QN_SCALE_JACOBIAN) {
    ierr = KSPSolve(snes->ksp,Y,W);CHKERRQ(ierr);
    SNESCheckKSPSolve(snes);
    ierr              = KSPGetIterationNumber(snes->ksp,&lits);CHKERRQ(ierr);
    snes->linear_its += lits;
    ierr              = VecCopy(W,Y);CHKERRQ(ierr);
  } else {
    ierr = VecScale(Y,qn->scaling);CHKERRQ(ierr);
  }

  /* inward recursion starting at the first update and working forward */
  if (l > 0) {
    for (i = 0; i < l-1; i++) {
      j    = (it+i-l)%l;
      k    = (it+i-l+1)%l;
      h    = (it-1)%l;
      ierr = VecDotBegin(U[j],U[h],&gdot);CHKERRQ(ierr);
      ierr = VecDotBegin(U[j],U[j],&udot);CHKERRQ(ierr);
      ierr = VecDotEnd(U[j],U[h],&gdot);CHKERRQ(ierr);
      ierr = VecDotEnd(U[j],U[j],&udot);CHKERRQ(ierr);
      ierr = VecAXPY(Y,PetscRealPart(gdot)/PetscRealPart(udot),T[k]);CHKERRQ(ierr);
      ierr = VecAXPY(Y,-(1.-qn->lambda[k])*PetscRealPart(gdot)/PetscRealPart(udot),T[j]);CHKERRQ(ierr);
      if (qn->monitor) {
        ierr = PetscViewerASCIIAddTab(qn->monitor,((PetscObject)snes)->tablevel+2);CHKERRQ(ierr);
        ierr = PetscViewerASCIIPrintf(qn->monitor, "it: %d k: %d gdot: %14.12e\n", it, k, PetscRealPart(gdot));CHKERRQ(ierr);
        ierr = PetscViewerASCIISubtractTab(qn->monitor,((PetscObject)snes)->tablevel+2);CHKERRQ(ierr);
      }
    }
  }
  PetscFunctionReturn(0);
}

/*@
   TSAdaptCheckStage - checks whether to accept a stage, (e.g. reject and change time step size if nonlinear solve fails)

   Collective on TSAdapt

   Input Arguments:
+  adapt - adaptive controller context
.  ts - time stepper
.  t - Current simulation time
-  Y - Current solution vector

   Output Arguments:
.  accept - PETSC_TRUE to accept the stage, PETSC_FALSE to reject

   Level: developer

.seealso:
@*/
PetscErrorCode TSAdaptCheckStage(TSAdapt adapt,TS ts,PetscReal t,Vec Y,PetscBool *accept)
{
  PetscErrorCode      ierr;
  SNESConvergedReason snesreason = SNES_CONVERGED_ITERATING;

  PetscFunctionBegin;
  PetscValidHeaderSpecific(adapt,TSADAPT_CLASSID,1);
  PetscValidHeaderSpecific(ts,TS_CLASSID,2);
  PetscValidIntPointer(accept,3);

  if (ts->snes) {ierr = SNESGetConvergedReason(ts->snes,&snesreason);CHKERRQ(ierr);}
  if (snesreason < 0) {
    *accept = PETSC_FALSE;
    if (++ts->num_snes_failures >= ts->max_snes_failures && ts->max_snes_failures > 0) {
      ts->reason = TS_DIVERGED_NONLINEAR_SOLVE;
      ierr = PetscInfo2(ts,"Step=%D, nonlinear solve failures %D greater than current TS allowed, stopping solve\n",ts->steps,ts->num_snes_failures);CHKERRQ(ierr);
      if (adapt->monitor) {
        ierr = PetscViewerASCIIAddTab(adapt->monitor,((PetscObject)adapt)->tablevel);CHKERRQ(ierr);
        ierr = PetscViewerASCIIPrintf(adapt->monitor,"    TSAdapt %s step %3D stage rejected t=%-11g+%10.3e, nonlinear solve failures %D greater than current TS allowed\n",((PetscObject)adapt)->type_name,ts->steps,(double)ts->ptime,(double)ts->time_step,ts->num_snes_failures);CHKERRQ(ierr);
        ierr = PetscViewerASCIISubtractTab(adapt->monitor,((PetscObject)adapt)->tablevel);CHKERRQ(ierr);
      }
    }
  } else {
    *accept = PETSC_TRUE;
    ierr = TSFunctionDomainError(ts,t,Y,accept);CHKERRQ(ierr);
    if(*accept && adapt->checkstage) {
      ierr = (*adapt->checkstage)(adapt,ts,t,Y,accept);CHKERRQ(ierr);
    }
  }

  if(!(*accept) && !ts->reason) {
    PetscReal dt,new_dt;
    ierr = TSGetTimeStep(ts,&dt);CHKERRQ(ierr);
    new_dt = dt * adapt->scale_solve_failed;
    ierr = TSSetTimeStep(ts,new_dt);CHKERRQ(ierr);
    adapt->timestepjustdecreased += adapt->timestepjustdecreased_delay;
    if (adapt->monitor) {
      ierr = PetscViewerASCIIAddTab(adapt->monitor,((PetscObject)adapt)->tablevel);CHKERRQ(ierr);
      ierr = PetscViewerASCIIPrintf(adapt->monitor,"    TSAdapt %s step %3D stage rejected (%s) t=%-11g+%10.3e retrying with dt=%-10.3e\n",((PetscObject)adapt)->type_name,ts->steps,SNESConvergedReasons[snesreason],(double)ts->ptime,(double)dt,(double)new_dt);CHKERRQ(ierr);
      ierr = PetscViewerASCIISubtractTab(adapt->monitor,((PetscObject)adapt)->tablevel);CHKERRQ(ierr);
    }
  }
  PetscFunctionReturn(0);
}

/*@C
   SNESMonitorDefault - Monitors progress of the SNES solvers (default).

   Collective on SNES

   Input Parameters:
+  snes - the SNES context
.  its - iteration number
.  fgnorm - 2-norm of residual
-  dummy - unused context

   Notes:
   This routine prints the residual norm at each iteration.

   Level: intermediate

.keywords: SNES, nonlinear, default, monitor, norm

.seealso: SNESMonitorSet(), SNESMonitorSolution()
@*/
PetscErrorCode  SNESMonitorDefault(SNES snes,PetscInt its,PetscReal fgnorm,void *dummy)
{
  PetscErrorCode ierr;
  PetscViewer    viewer = dummy ? (PetscViewer) dummy : PETSC_VIEWER_STDOUT_(((PetscObject)snes)->comm);

  PetscFunctionBegin;
  ierr = PetscViewerASCIIAddTab(viewer,((PetscObject)snes)->tablevel);CHKERRQ(ierr);
  ierr = PetscViewerASCIIPrintf(viewer,"%3D SNES Function norm %14.12e \n",its,(double)fgnorm);CHKERRQ(ierr);
  ierr = PetscViewerASCIISubtractTab(viewer,((PetscObject)snes)->tablevel);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}

/*@C
   SNESMonitorDefault - Monitors progress of the SNES solvers (default).

   Collective on SNES

   Input Parameters:
+  snes - the SNES context
.  its - iteration number
.  fgnorm - 2-norm of residual
-  dummy - unused context

   Notes:
   This routine prints the residual norm at each iteration.

   Level: intermediate

.keywords: SNES, nonlinear, default, monitor, norm

.seealso: SNESMonitorSet(), SNESMonitorSolution()
@*/
PetscErrorCode  SNESMonitorDefault(SNES snes,PetscInt its,PetscReal fgnorm,void *dummy)
{
  PetscErrorCode ierr;
  PetscViewer    viewer = (PetscViewer) dummy;

  PetscFunctionBegin;
  PetscValidHeaderSpecific(viewer,PETSC_VIEWER_CLASSID,4);
  ierr = PetscViewerASCIIAddTab(viewer,((PetscObject)snes)->tablevel);CHKERRQ(ierr);
  ierr = PetscViewerASCIIPrintf(viewer,"%3D SNES Function norm %14.12e \n",its,(double)fgnorm);CHKERRQ(ierr);
  ierr = PetscViewerASCIISubtractTab(viewer,((PetscObject)snes)->tablevel);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}

/*@C
   TSAdaptChoose - choose which method and step size to use for the next step

   Collective on TSAdapt

   Input Arguments:
+  adapt - adaptive contoller
-  h - current step size

   Output Arguments:
+  next_sc - optional, scheme to use for the next step
.  next_h - step size to use for the next step
-  accept - PETSC_TRUE to accept the current step, PETSC_FALSE to repeat the current step with the new step size

   Note:
   The input value of parameter accept is retained from the last time step, so it will be PETSC_FALSE if the step is
   being retried after an initial rejection.

   Level: developer

.seealso: TSAdapt, TSAdaptCandidatesClear(), TSAdaptCandidateAdd()
@*/
PetscErrorCode TSAdaptChoose(TSAdapt adapt,TS ts,PetscReal h,PetscInt *next_sc,PetscReal *next_h,PetscBool *accept)
{
  PetscErrorCode ierr;
  PetscInt       ncandidates = adapt->candidates.n;
  PetscInt       scheme = 0;
  PetscReal      wlte = -1.0;
  PetscReal      wltea = -1.0;
  PetscReal      wlter = -1.0;

  PetscFunctionBegin;
  PetscValidHeaderSpecific(adapt,TSADAPT_CLASSID,1);
  PetscValidHeaderSpecific(ts,TS_CLASSID,2);
  if (next_sc) PetscValidIntPointer(next_sc,4);
  PetscValidPointer(next_h,5);
  PetscValidIntPointer(accept,6);
  if (next_sc) *next_sc = 0;

  /* Do not mess with adaptivity while handling events*/
  if (ts->event && ts->event->status != TSEVENT_NONE) {
    *next_h = h;
    *accept = PETSC_TRUE;
    PetscFunctionReturn(0);
  }

  ierr = (*adapt->ops->choose)(adapt,ts,h,&scheme,next_h,accept,&wlte,&wltea,&wlter);CHKERRQ(ierr);
  if (scheme < 0 || (ncandidates > 0 && scheme >= ncandidates)) SETERRQ2(PetscObjectComm((PetscObject)adapt),PETSC_ERR_ARG_OUTOFRANGE,"Chosen scheme %D not in valid range 0..%D",scheme,ncandidates-1);
  if (*next_h < 0) SETERRQ1(PetscObjectComm((PetscObject)adapt),PETSC_ERR_ARG_OUTOFRANGE,"Computed step size %g must be positive",(double)*next_h);
  if (next_sc) *next_sc = scheme;

  if (*accept && ts->exact_final_time == TS_EXACTFINALTIME_MATCHSTEP) {
    /* Increase/reduce step size if end time of next step is close to or overshoots max time */
    PetscReal t = ts->ptime + ts->time_step, h = *next_h;
    PetscReal tend = t + h, tmax = ts->max_time, hmax = tmax - t;
    PetscReal a = (PetscReal)(1.0 + adapt->matchstepfac[0]);
    PetscReal b = adapt->matchstepfac[1];
    if (t < tmax && tend > tmax) *next_h = hmax;
    if (t < tmax && tend < tmax && h*b > hmax) *next_h = hmax/2;
    if (t < tmax && tend < tmax && h*a > hmax) *next_h = hmax;
  }

  if (adapt->monitor) {
    const char *sc_name = (scheme < ncandidates) ? adapt->candidates.name[scheme] : "";
    ierr = PetscViewerASCIIAddTab(adapt->monitor,((PetscObject)adapt)->tablevel);CHKERRQ(ierr);
    if (wlte < 0) {
      ierr = PetscViewerASCIIPrintf(adapt->monitor,"    TSAdapt %s %s %D:%s step %3D %s t=%-11g+%10.3e dt=%-10.3e\n",((PetscObject)adapt)->type_name,((PetscObject)ts)->type_name,scheme,sc_name,ts->steps,*accept ? "accepted" : "rejected",(double)ts->ptime,(double)h,(double)*next_h);CHKERRQ(ierr);
    } else {
      ierr = PetscViewerASCIIPrintf(adapt->monitor,"    TSAdapt %s %s %D:%s step %3D %s t=%-11g+%10.3e dt=%-10.3e wlte=%5.3g  wltea=%5.3g wlter=%5.3g\n",((PetscObject)adapt)->type_name,((PetscObject)ts)->type_name,scheme,sc_name,ts->steps,*accept ? "accepted" : "rejected",(double)ts->ptime,(double)h,(double)*next_h,(double)wlte,(double)wltea,(double)wlter);CHKERRQ(ierr);
    }
    ierr = PetscViewerASCIISubtractTab(adapt->monitor,((PetscObject)adapt)->tablevel);CHKERRQ(ierr);
  }
  PetscFunctionReturn(0);
}

/*@C
   KSPMonitorDefault - Print the residual norm at each iteration of an
   iterative solver.

   Collective on KSP

   Input Parameters:
+  ksp   - iterative context
.  n     - iteration number
.  rnorm - 2-norm (preconditioned) residual value (may be estimated).
-  dummy - an ASCII PetscViewer

   Level: intermediate

.keywords: KSP, default, monitor, residual

.seealso: KSPMonitorSet(), KSPMonitorTrueResidualNorm(), KSPMonitorLGResidualNormCreate()
@*/
PetscErrorCode  KSPMonitorDefault(KSP ksp,PetscInt n,PetscReal rnorm,void *dummy)
{
  PetscErrorCode ierr;
  PetscViewer    viewer = (PetscViewer) dummy;

  PetscFunctionBegin;
  PetscValidHeaderSpecific(viewer,PETSC_VIEWER_CLASSID,4);
  ierr = PetscViewerASCIIAddTab(viewer,((PetscObject)ksp)->tablevel);CHKERRQ(ierr);
  if (n == 0 && ((PetscObject)ksp)->prefix) {
    ierr = PetscViewerASCIIPrintf(viewer,"  Residual norms for %s solve.\n",((PetscObject)ksp)->prefix);CHKERRQ(ierr);
  }
  ierr = PetscViewerASCIIPrintf(viewer,"%3D KSP Residual norm %14.12e \n",n,(double)rnorm);CHKERRQ(ierr);
  ierr = PetscViewerASCIISubtractTab(viewer,((PetscObject)ksp)->tablevel);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}

static PetscErrorCode  
MonitorNorms(SNES snes, PetscInt its, PetscReal fgnorm, void *dummy)
{
  PetscViewer    viewer = PETSC_VIEWER_STDOUT_WORLD;

  Vec dx;
  SNESGetSolutionUpdate(snes, &dx);
  PetscReal dxnorm;
  VecNorm(dx, NORM_2, &dxnorm);
  PetscInt tablevel;
  PetscObjectGetTabLevel(((PetscObject)snes), &tablevel);
  PetscViewerASCIIAddTab(viewer, tablevel);
  PetscViewerASCIIPrintf(viewer,"%3D SNES Function norm %14.12e, Solution residual norm %14.12e\n",
                         its, (double)fgnorm, (double)dxnorm);
  PetscViewerASCIISubtractTab(viewer, tablevel);
  return(0);
}

/*
     Default (short) SNES Monitor, same as SNESMonitorDefault() except
  it prints fewer digits of the residual as the residual gets smaller.
  This is because the later digits are meaningless and are often
  different on different machines; by using this routine different
  machines will usually generate the same output.
*/
PetscErrorCode  SNESMonitorDefaultShort(SNES snes,PetscInt its,PetscReal fgnorm,void *dummy)
{
  PetscErrorCode ierr;
  PetscViewer    viewer = dummy ? (PetscViewer) dummy : PETSC_VIEWER_STDOUT_(((PetscObject)snes)->comm);

  PetscFunctionBegin;
  ierr = PetscViewerASCIIAddTab(viewer,((PetscObject)snes)->tablevel);CHKERRQ(ierr);
  if (fgnorm > 1.e-9) {
    ierr = PetscViewerASCIIPrintf(viewer,"%3D SNES Function norm %G \n",its,fgnorm);CHKERRQ(ierr);
  } else if (fgnorm > 1.e-11){
    ierr = PetscViewerASCIIPrintf(viewer,"%3D SNES Function norm %5.3e \n",its,fgnorm);CHKERRQ(ierr);
  } else {
    ierr = PetscViewerASCIIPrintf(viewer,"%3D SNES Function norm < 1.e-11\n",its);CHKERRQ(ierr);
  }
  ierr = PetscViewerASCIISubtractTab(viewer,((PetscObject)snes)->tablevel);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}