petscconvergencemodule Module Reference

Data Types
type	petsccnvgctxtype
	x vector from the previous iteration More...
interface	CnvgCheckFunc
interface	CnvgDestroyFunc
interface	KSPSetConvergenceTest

Functions/Subroutines
subroutine	create (this, mat, settings, summary)
subroutine, public	petsc_check_convergence (ksp, n, rnorm_L2, flag, context, ierr)
	Routine to check the convergence. This is called. More...
function	apply_check (ctx, nit, dvmax, rnorm_inf, rnorm_L2)
	Apply the IMS convergence check. More...
subroutine	destroy (this)

Variables
real(dp), parameter, private	rnorm_l2_tol = DPREC
	Context for the custom convergence check. More...

Function/Subroutine Documentation

apply_check()

function petscconvergencemodule::apply_check ( class(petsccnvgctxtype)  ctx, integer(i4b)  nit, real(dp)  dvmax, real(dp)  rnorm_inf, real(dp)  rnorm_L2  )

private

Parameters

nit	iteration number
dvmax	infinity norm of dep. var. change
rnorm_inf	infinity norm of residual change
rnorm_l2	L2-norm of residual change
rnorm_l2	the convergence status

Definition at line 234 of file PetscConvergence.F90.

    use tdismodule, only: kstp
    use imslinearbasemodule, only: ims_base_testcnvg, ims_base_epfact
    class(PetscCnvgCtxType) :: ctx
    integer(I4B) :: nit !< iteration number
    real(DP) :: dvmax !< infinity norm of dep. var. change
    real(DP) :: rnorm_inf !< infinity norm of residual change
    real(DP) :: rnorm_L2 !< L2-norm of residual change
    kspconvergedreason :: flag !< the convergence status
    ! local
    real(DP) :: epfact
    real(DP) :: rcnvg
 
    ! Set to 'not converged'
    flag = ksp_converged_iterating
    ctx%icnvg_ims = 0
 
    epfact = ims_base_epfact(ctx%icnvgopt, kstp)
 
    if (ctx%icnvgopt == 2 .or. &
        ctx%icnvgopt == 3 .or. &
        ctx%icnvgopt == 4) then
      rcnvg = rnorm_l2
    else
      rcnvg = rnorm_inf
    end if
    call ims_base_testcnvg(ctx%icnvgopt, ctx%icnvg_ims, nit, &
                           dvmax, rcnvg, ctx%rnorm_L2_init, &
                           epfact, ctx%dvclose, ctx%rclose)
 
    if (ctx%icnvg_ims /= 0) then
      ! Set to 'converged'
      flag = ksp_converged_happy_breakdown
    end if
 

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create()

subroutine petscconvergencemodule::create ( class(petsccnvgctxtype)  this, pointer  mat, type(imslinearsettingstype), pointer  settings, type(convergencesummarytype), pointer  summary  )

private

Definition at line 68 of file PetscConvergence.F90.

    class(PetscCnvgCtxType) :: this
    mat, pointer :: mat
    type(ImsLinearSettingsType), pointer :: settings
    type(ConvergenceSummaryType), pointer :: summary
    ! local
    petscerrorcode :: ierr
 
    this%icnvg_ims = 0
    this%icnvgopt = settings%icnvgopt
    this%dvclose = settings%dvclose
    this%rclose = settings%rclose
    this%max_its = settings%iter1
    this%cnvg_summary => summary
    call matcreatevecs(mat, this%x_old, petsc_null_vec, ierr)
    chkerrq(ierr)
    call matcreatevecs(mat, this%delta_x, petsc_null_vec, ierr)
    chkerrq(ierr)
    call matcreatevecs(mat, this%residual, petsc_null_vec, ierr)
    chkerrq(ierr)
 

destroy()

subroutine petscconvergencemodule::destroy

(

class(petsccnvgctxtype)

this

)

Definition at line 271 of file PetscConvergence.F90.

    class(PetscCnvgCtxType) :: this
    ! local
    integer(I4B) :: ierr
 
    call vecdestroy(this%x_old, ierr)
    chkerrq(ierr)
    call vecdestroy(this%delta_x, ierr)
    chkerrq(ierr)
    call vecdestroy(this%residual, ierr)
    chkerrq(ierr)
 

petsc_check_convergence()

subroutine, public petscconvergencemodule::petsc_check_convergence	(		ksp,
			n,
			rnorm_L2,
			flag,
		class(petsccnvgctxtype), pointer	context,
			ierr
	)

Parameters

context

error

Definition at line 93 of file PetscConvergence.F90.

    ksp :: ksp !< Iterative context
    petscint :: n !< Iteration number
    petscreal :: rnorm_l2 !< 2-norm (preconditioned) residual value
    kspconvergedreason :: flag !< Converged reason
    class(PetscCnvgCtxType), pointer :: context !< context
    petscerrorcode :: ierr !< error
    ! local
    petscreal, parameter :: min_one = -1.0
    petscreal, dimension(:), pointer :: local_dx, local_res
    petscreal :: xnorm_inf_ims, rnorm_inf_ims, rnorm_l2_ims
    petscreal :: dvmax_model, rmax_model
    petscint :: idx_dv, idx_r
    vec :: x, rhs
    mat :: amat
    type(ConvergenceSummaryType), pointer :: summary
    petscint :: iter_cnt
    petscint :: i, j, istart, iend
 
    summary => context%cnvg_summary
 
    ! NB: KSPBuildResidual needs to have its vector destroyed
    ! to avoid a memory leak, KSPBuildSolution doesn't...
    call kspbuildsolution(ksp, petsc_null_vec, x, ierr)
    chkerrq(ierr)
 
    call kspgetrhs(ksp, rhs, ierr)
    chkerrq(ierr)
 
    call kspgetoperators(ksp, amat, petsc_null_mat, ierr)
    chkerrq(ierr)
 
    call matmult(amat, x, context%residual, ierr)
    chkerrq(ierr)
 
    ! y = x + beta y (i.e. r = b - A*x)
    call vecaypx(context%residual, -1.0_dp, rhs, ierr)
    chkerrq(ierr)
 
    call vecnorm(context%residual, norm_2, rnorm_l2_ims, ierr)
    chkerrq(ierr)
 
    ! n == 0 is before the iteration starts
    if (n == 0) then
      context%rnorm_L2_init = rnorm_l2_ims
      if (rnorm_l2 < rnorm_l2_tol) then
        ! exact solution found
        flag = ksp_converged_happy_breakdown
      else
        call veccopy(x, context%x_old, ierr)
        chkerrq(ierr)
        flag = ksp_converged_iterating
      end if
      ! early return
      return
    end if
 
    ! increment iteration counter
    summary%iter_cnt = summary%iter_cnt + 1
    iter_cnt = summary%iter_cnt
 
    if (summary%nitermax > 1) then
      summary%itinner(iter_cnt) = n
      do i = 1, summary%convnmod
        summary%convdvmax(i, iter_cnt) = dzero
        summary%convlocdv(i, iter_cnt) = 0
        summary%convrmax(i, iter_cnt) = dzero
        summary%convlocr(i, iter_cnt) = 0
      end do
    end if
 
    call vecwaxpy(context%delta_x, min_one, context%x_old, x, ierr)
    chkerrq(ierr)
 
    call vecnorm(context%delta_x, norm_infinity, xnorm_inf_ims, ierr)
    chkerrq(ierr)
 
    rnorm_inf_ims = 0.0
    if (context%icnvgopt == 0 .or. context%icnvgopt == 1) then
      call vecnorm(context%residual, norm_infinity, rnorm_inf_ims, ierr)
      chkerrq(ierr)
    end if
 
    call veccopy(x, context%x_old, ierr)
    chkerrq(ierr)
 
    ! get dv and dr per local model (readonly!)
    call vecgetarrayreadf90(context%delta_x, local_dx, ierr)
    chkerrq(ierr)
    call vecgetarrayreadf90(context%residual, local_res, ierr)
    chkerrq(ierr)
    do i = 1, summary%convnmod
      ! reset
      dvmax_model = dzero
      idx_dv = 0
      rmax_model = dzero
      idx_r = 0
      ! get first and last model index
      istart = summary%model_bounds(i)
      iend = summary%model_bounds(i + 1) - 1
      do j = istart, iend
        if (abs(local_dx(j)) > abs(dvmax_model)) then
          dvmax_model = local_dx(j)
          idx_dv = j
        end if
        if (abs(local_res(j)) > abs(rmax_model)) then
          rmax_model = local_res(j)
          idx_r = j
        end if
      end do
      if (summary%nitermax > 1) then
        summary%convdvmax(i, iter_cnt) = dvmax_model
        summary%convlocdv(i, iter_cnt) = idx_dv
        summary%convrmax(i, iter_cnt) = rmax_model
        summary%convlocr(i, iter_cnt) = idx_r
      end if
    end do
    call vecrestorearrayf90(context%delta_x, local_dx, ierr)
    chkerrq(ierr)
    call vecrestorearrayf90(context%residual, local_res, ierr)
    chkerrq(ierr)
 
    if (rnorm_l2 < rnorm_l2_tol) then
      ! exact solution, set to 'converged'
      flag = ksp_converged_happy_breakdown
    else
      ! IMS check on convergence
      flag = apply_check(context, n, xnorm_inf_ims, rnorm_inf_ims, rnorm_l2_ims)
    end if
 
    if (flag == ksp_converged_iterating) then
      ! not yet converged, max. iters reached? Then stop.
      if (n == context%max_its) then
        flag = ksp_diverged_its
      end if
    end if
 

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Variable Documentation

rnorm_l2_tol

real(dp), parameter, private petscconvergencemodule::rnorm_l2_tol = DPREC

private

Definition at line 16 of file PetscConvergence.F90.

  real(DP), private, parameter :: RNORM_L2_TOL = dprec