Data Types
type	atstype

Functions/Subroutines
logical(lgp) function	isadaptiveperiod (this, kper)
	@ brief Determine if period is adaptive More...

subroutine	ats_init (this, inunit, nper_tdis)
	@ brief Create ATS object More...

subroutine	ats_allocate_scalars (this)
	@ brief Allocate scalars More...

subroutine	ats_allocate_arrays (this)
	@ brief Allocate arrays More...

subroutine	ats_da (this)
	@ brief Deallocate variables More...

subroutine	ats_read_options (this)
	@ brief Read options More...

subroutine	ats_read_dimensions (this)
	@ brief Read dimensions More...

subroutine	ats_read_timing (this)
	@ brief Read timing More...

subroutine	ats_process_input (this)
	@ brief Process input More...

subroutine	ats_input_table (this)
	@ brief Write input table More...

subroutine	ats_check_timing (this)
	@ brief Check timing More...

subroutine	ats_period_message (this, kper)
	@ brief Write period message More...

subroutine	ats_submit_delt (this, kstp, kper, dt, sloc, idir)
	@ brief Allow and external caller to submit preferred time step More...

subroutine	ats_set_delt (this, kstp, kper, pertim, perlencurrent, delt)
	@ brief Set time step More...

subroutine	ats_reset_delt (this, kstp, kper, lastStepFailed, delt, finishedTrying)
	@ brief Reset time step because failure has occurred More...

subroutine	ats_set_endofperiod (this, kper, pertim, perlencurrent, endofperiod)
	@ brief Set end of period indicator More...

Function/Subroutine Documentation

◆ ats_allocate_arrays()

subroutine adaptivetimestepmodule::ats_allocate_arrays ( class(atstype) this )

Allocate and initialize arrays for the ATS package.

Definition at line 148 of file ats.f90.

     ! -- modules
     use memorymanagermodule, only: mem_allocate
     ! -- dummy
     class(AtsType) :: this
     ! -- local
     integer(I4B) :: n
     !
     call mem_allocate(this%kperats, this%nper, 'KPERATS', 'ATS')
     call mem_allocate(this%iperats, this%maxats, 'IPERATS', 'ATS')
     call mem_allocate(this%dt0, this%maxats, 'DT0', 'ATS')
     call mem_allocate(this%dtmin, this%maxats, 'DTMIN', 'ATS')
     call mem_allocate(this%dtmax, this%maxats, 'DTMAX', 'ATS')
     call mem_allocate(this%dtadj, this%maxats, 'DTADJ', 'ATS')
     call mem_allocate(this%dtfailadj, this%maxats, 'DTFAILADJ', 'ATS')
     !
     ! -- initialize kperats
     do n = 1, this%nper
       this%kperats(n) = 0
     end do
     !
     ! -- initialize
     do n = 1, this%maxats
       this%iperats(n) = 0
       this%dt0(n) = dzero
       this%dtmin(n) = dzero
       this%dtmax(n) = dzero
       this%dtadj(n) = dzero
       this%dtfailadj(n) = dzero
     end do

◆ ats_allocate_scalars()

subroutine adaptivetimestepmodule::ats_allocate_scalars ( class(atstype) this )

private

Allocate and initialize scalars for the ATS package.

Definition at line 127 of file ats.f90.

     ! -- modules
     use memorymanagermodule, only: mem_allocate
     ! -- dummy
     class(AtsType) :: this
     ! -- memory manager variables
     call mem_allocate(this%nper, 'NPER', 'ATS')
     call mem_allocate(this%maxats, 'MAXATS', 'ATS')
     call mem_allocate(this%dtstable, 'DTSTABLE', 'ATS')
     !
     ! -- Initialize variables
     this%nper = 0
     this%maxats = 0
     this%dtstable = dnodata

◆ ats_check_timing()

subroutine adaptivetimestepmodule::ats_check_timing ( class(atstype) this )

Perform a check on the input data to make sure values are within required ranges.

Definition at line 415 of file ats.f90.

     ! -- dummy
     class(AtsType) :: this
  
     integer(I4B) :: n
     write (iout, '(1x,a)') 'PROCESSING ATS INPUT'
     do n = 1, this%maxats
       !
       ! -- check iperats
       if (this%iperats(n) < 1) then
         write (errmsg, '(a, i0, a, i0)') &
           'IPERATS must be greater than zero.  Found ', this%iperats(n), &
           ' for ATS PERIODDATA record ', n
         call store_error(errmsg)
       end if
       if (this%iperats(n) > this%nper) then
         write (warnmsg, '(a, i0, a, i0)') &
           'IPERATS greater than NPER.  Found ', this%iperats(n), &
           ' for ATS PERIODDATA record ', n
         call store_warning(warnmsg)
       end if
       !
       ! -- check dt0
       if (this%dt0(n) < dzero) then
         write (errmsg, '(a, g15.7, a, i0)') &
           'DT0 must be >= zero.  Found ', this%dt0(n), &
           ' for ATS PERIODDATA record ', n
         call store_error(errmsg)
       end if
       !
       ! -- check dtmin
       if (this%dtmin(n) <= dzero) then
         write (errmsg, '(a, g15.7, a, i0)') &
           'DTMIN must be > zero.  Found ', this%dtmin(n), &
           ' for ATS PERIODDATA record ', n
         call store_error(errmsg)
       end if
       !
       ! -- check dtmax
       if (this%dtmax(n) <= dzero) then
         write (errmsg, '(a, g15.7, a, i0)') &
           'DTMAX must be > zero.  Found ', this%dtmax(n), &
           ' for ATS PERIODDATA record ', n
         call store_error(errmsg)
       end if
       !
       ! -- check dtmin <= dtmax
       if (this%dtmin(n) > this%dtmax(n)) then
         write (errmsg, '(a, 2g15.7, a, i0)') &
           'DTMIN must be < dtmax.  Found ', this%dtmin(n), this%dtmax(n), &
           ' for ATS PERIODDATA record ', n
         call store_error(errmsg)
       end if
       !
       ! -- check dtadj
       if (this%dtadj(n) .ne. dzero .and. this%dtadj(n) < done) then
         write (errmsg, '(a, g15.7, a, i0)') &
           'DTADJ must be 0 or >= 1.0.  Found ', this%dtadj(n), &
           ' for ATS PERIODDATA record ', n
         call store_error(errmsg)
       end if
       !
       ! -- check dtfailadj
       if (this%dtfailadj(n) .ne. dzero .and. this%dtfailadj(n) < done) then
         write (errmsg, '(a, g15.7, a, i0)') &
           'DTFAILADJ must be 0 or >= 1.0.  Found ', this%dtfailadj(n), &
           ' for ATS PERIODDATA record ', n
         call store_error(errmsg)
       end if
  
     end do
     !
     ! -- Check for errors
     if (count_errors() > 0) then
       call this%parser%StoreErrorUnit()
     end if
     write (iout, '(1x,a)') 'DONE PROCESSING ATS INPUT'

Here is the call graph for this function:

◆ ats_da()

subroutine adaptivetimestepmodule::ats_da ( class(atstype) this )

Deallocate all ATS variables.

Definition at line 185 of file ats.f90.

     use memorymanagermodule, only: mem_deallocate
     ! -- dummy
     class(AtsType) :: this
     ! -- Scalars
     call mem_deallocate(this%nper)
     call mem_deallocate(this%maxats)
     call mem_deallocate(this%dtstable)
     !
     ! -- Arrays
     call mem_deallocate(this%kperats)
     call mem_deallocate(this%iperats)
     call mem_deallocate(this%dt0)
     call mem_deallocate(this%dtmin)
     call mem_deallocate(this%dtmax)
     call mem_deallocate(this%dtadj)
     call mem_deallocate(this%dtfailadj)

◆ ats_init()

subroutine adaptivetimestepmodule::ats_init	(	class(atstype)	this,
		integer(i4b), intent(in)	inunit,
		integer(i4b), intent(in)	nper_tdis
	)

private

Create a new ATS object, and read and check input.

Definition at line 75 of file ats.f90.

     ! -- modules
     ! -- dummy
     class(AtsType) :: this
     integer(I4B), intent(in) :: inunit
     integer(I4B), intent(in) :: nper_tdis
     ! -- local
     ! -- formats
     character(len=*), parameter :: fmtheader = &
         "(1X,/1X,'ATS -- ADAPTIVE TIME STEP PACKAGE,',   /                  &
         &' VERSION 1 : 03/18/2021 - INPUT READ FROM UNIT ',I0)"
     !
     ! -- Allocate the scalar variables
     call this%ats_allocate_scalars()
     !
     ! -- Identify package
     write (iout, fmtheader) inunit
     !
     ! -- Initialize block parser
     call this%parser%initialize(inunit, iout)
     !
     ! -- Read options
     call this%ats_read_options()
     !
     ! -- store tdis nper in nper
     this%nper = nper_tdis
     !
     ! -- Read dimensions and then allocate arrays
     call this%ats_read_dimensions()
     call this%ats_allocate_arrays()
     !
     ! -- Read timing
     call this%ats_read_timing()
     !
     ! -- Echo input data to table
     call this%ats_input_table()
     !
     ! -- Check timing
     call this%ats_check_timing()
     !
     ! -- Process input
     call this%ats_process_input()
     !
     ! -- Close the file
     call this%parser%Clear()

◆ ats_input_table()

subroutine adaptivetimestepmodule::ats_input_table ( class(atstype) this )

private

Write a table showing the ATS input read from the perioddata block.

Definition at line 363 of file ats.f90.

     use tablemodule, only: tabletype, table_cr
     ! -- dummy
     class(AtsType) :: this
  
     integer(I4B) :: n
     character(len=LINELENGTH) :: tag
     type(TableType), pointer :: inputtab => null()
     !
     ! -- setup table
     call table_cr(inputtab, 'ATS', 'ATS PERIOD DATA')
     call inputtab%table_df(this%maxats, 7, iout)
     !
     ! add columns
     tag = 'RECORD'
     call inputtab%initialize_column(tag, 10, alignment=tableft)
     tag = 'IPERATS'
     call inputtab%initialize_column(tag, 10, alignment=tableft)
     tag = 'DT0'
     call inputtab%initialize_column(tag, 10, alignment=tabcenter)
     tag = 'DTMIN'
     call inputtab%initialize_column(tag, 10, alignment=tabcenter)
     tag = 'DTMAX'
     call inputtab%initialize_column(tag, 10, alignment=tabcenter)
     tag = 'DTADJ'
     call inputtab%initialize_column(tag, 10, alignment=tabcenter)
     tag = 'DTFAILADJ'
     call inputtab%initialize_column(tag, 10, alignment=tabcenter)
     !
     ! -- write the data
     do n = 1, this%maxats
       call inputtab%add_term(n)
       call inputtab%add_term(this%iperats(n))
       call inputtab%add_term(this%dt0(n))
       call inputtab%add_term(this%dtmin(n))
       call inputtab%add_term(this%dtmax(n))
       call inputtab%add_term(this%dtadj(n))
       call inputtab%add_term(this%dtfailadj(n))
     end do
     !
     ! -- deallocate the table
     call inputtab%table_da()
     deallocate (inputtab)
     nullify (inputtab)

Here is the call graph for this function:

◆ ats_period_message()

subroutine adaptivetimestepmodule::ats_period_message	(	class(atstype)	this,
		integer(i4b), intent(in)	kper
	)

private

Write message to mfsim.lst file with information on ATS settings for this period.

Definition at line 500 of file ats.f90.

     ! -- dummy
     class(AtsType) :: this
     integer(I4B), intent(in) :: kper
     ! -- local
     integer(I4B) :: n
     character(len=*), parameter :: fmtspts = &
     "(28X,'ATS IS OVERRIDING TIME STEPPING FOR THIS PERIOD',/                  &
       &28X,'INITIAL TIME STEP SIZE                 (DT0) = ',G15.7,/           &
       &28X,'MINIMUM TIME STEP SIZE               (DTMIN) = ',G15.7,/           &
       &28X,'MAXIMUM TIME STEP SIZE               (DTMAX) = ',G15.7,/           &
       &28X,'MULTIPLIER/DIVIDER FOR TIME STEP     (DTADJ) = ',G15.7,/           &
       &28X,'DIVIDER FOR FAILED TIME STEP     (DTFAILADJ) = ',G15.7,/           &
       &)"
     n = this%kperats(kper)
     write (iout, fmtspts) this%dt0(n), this%dtmin(n), this%dtmax(n), &
       this%dtadj(n), this%dtfailadj(n)

◆ ats_process_input()

subroutine adaptivetimestepmodule::ats_process_input ( class(atstype) this )

private

Process ATS input by filling the kperats array.

Definition at line 342 of file ats.f90.

     ! -- dummy
     class(AtsType) :: this
  
     integer(I4B) :: kkper
     integer(I4B) :: n
     !
     ! -- fill kperats for valid iperats values
     do n = 1, this%maxats
       kkper = this%iperats(n)
       if (kkper > 0 .and. kkper <= this%nper) then
         this%kperats(kkper) = n
       end if
     end do

◆ ats_read_dimensions()

subroutine adaptivetimestepmodule::ats_read_dimensions ( class(atstype) this )

private

Read dimensions from ATS input file.

Definition at line 246 of file ats.f90.

     ! -- dummy
     class(AtsType) :: this
     ! -- local
     character(len=LINELENGTH) :: keyword
     integer(I4B) :: ierr
     logical :: isfound, endOfBlock
     ! -- formats
     character(len=*), parameter :: fmtmaxats = &
       &"(1X,I0,' ADAPTIVE TIME STEP RECORDS(S) WILL FOLLOW IN PERIODDATA')"
     !
     ! -- get DIMENSIONS block
     call this%parser%GetBlock('DIMENSIONS', isfound, ierr, &
                               supportopenclose=.true.)
     !
     ! -- parse block if detected
     if (isfound) then
       write (iout, '(1x,a)') 'PROCESSING ATS DIMENSIONS'
       do
         call this%parser%GetNextLine(endofblock)
         if (endofblock) exit
         call this%parser%GetStringCaps(keyword)
         select case (keyword)
         case ('MAXATS')
           this%maxats = this%parser%GetInteger()
           write (iout, fmtmaxats) this%maxats
         case default
           write (errmsg, '(a,a)') 'Unknown ATS dimension: ', &
             trim(keyword)
           call store_error(errmsg)
           call this%parser%StoreErrorUnit()
         end select
       end do
       write (iout, '(1x,a)') 'END OF ATS DIMENSIONS'
     else
       write (errmsg, '(a)') 'Required DIMENSIONS block not found.'
       call store_error(errmsg)
       call this%parser%StoreErrorUnit()
     end if

Here is the call graph for this function:

◆ ats_read_options()

subroutine adaptivetimestepmodule::ats_read_options ( class(atstype) this )

Read options from ATS input file.

Definition at line 209 of file ats.f90.

     ! -- dummy
     class(AtsType) :: this
     ! -- local
     character(len=LINELENGTH) :: keyword
     integer(I4B) :: ierr
     logical :: isfound, endOfBlock
     ! -- formats
     !
     ! -- get options block
     call this%parser%GetBlock('OPTIONS', isfound, ierr, &
                               supportopenclose=.true., blockrequired=.false.)
     !
     ! -- parse options block if detected
     if (isfound) then
       write (iout, '(1x,a)') 'PROCESSING ATS OPTIONS'
       do
         call this%parser%GetNextLine(endofblock)
         if (endofblock) exit
         call this%parser%GetStringCaps(keyword)
         select case (keyword)
         case default
           write (errmsg, '(a,a)') 'Unknown ATS option: ', &
             trim(keyword)
           call store_error(errmsg)
           call this%parser%StoreErrorUnit()
         end select
       end do
       write (iout, '(1x,a)') 'END OF ATS OPTIONS'
     end if

Here is the call graph for this function:

◆ ats_read_timing()

subroutine adaptivetimestepmodule::ats_read_timing ( class(atstype) this )

private

Read timing information from ATS input file.

Definition at line 292 of file ats.f90.

     ! -- modules
     ! -- dummy
     class(AtsType) :: this
     ! -- local
     integer(I4B) :: ierr
     integer(I4B) :: n
     logical :: isfound, endOfBlock
     ! -- formats
     !
     ! -- get PERIODDATA block
     call this%parser%GetBlock('PERIODDATA', isfound, ierr, &
                               supportopenclose=.true.)
     !
     ! -- parse block if detected
     if (isfound) then
       write (iout, '(1x,a)') 'READING ATS PERIODDATA'
       do n = 1, this%maxats
         call this%parser%GetNextLine(endofblock)
         if (endofblock) exit
         !
         ! -- fill the ats data arrays
         this%iperats(n) = this%parser%GetInteger()
         this%dt0(n) = this%parser%GetDouble()
         this%dtmin(n) = this%parser%GetDouble()
         this%dtmax(n) = this%parser%GetDouble()
         this%dtadj(n) = this%parser%GetDouble()
         this%dtfailadj(n) = this%parser%GetDouble()
       end do
       !
       ! -- Close the block
       call this%parser%terminateblock()
       !
       ! -- Check for errors
       if (count_errors() > 0) then
         call this%parser%StoreErrorUnit()
       end if
       write (iout, '(1x,a)') 'END READING ATS PERIODDATA'
     else
       write (errmsg, '(a)') 'Required PERIODDATA block not found.'
       call store_error(errmsg)
       call this%parser%StoreErrorUnit()
     end if

Here is the call graph for this function:

◆ ats_reset_delt()

subroutine adaptivetimestepmodule::ats_reset_delt	(	class(atstype)	this,
		integer(i4b), intent(in)	kstp,
		integer(i4b), intent(in)	kper,
		integer(i4b), intent(in)	lastStepFailed,
		real(dp), intent(inout)	delt,
		logical, intent(inout)	finishedTrying
	)

private

Reset the time step using dtfailadj because the time step did not converge.

Definition at line 642 of file ats.f90.

     ! -- modules
     ! -- dummy
     class(AtsType) :: this
     integer(I4B), intent(in) :: kstp
     integer(I4B), intent(in) :: kper
     integer(I4B), intent(in) :: lastStepFailed
     real(DP), intent(inout) :: delt
     logical, intent(inout) :: finishedTrying
     ! -- local
     integer(I4B) :: n
     real(DP) :: delt_temp
     real(DP) :: tsfact
     ! -- formats
     character(len=*), parameter :: fmttsi = &
       "(1X, 'Failed solution for step ', i0, ' and period ', i0, &
       &' will be retried using time step of ', G15.7)"
     if (this%isAdaptivePeriod(kper)) then
       if (laststepfailed /= 0) then
         delt_temp = delt
         n = this%kperats(kper)
         tsfact = this%dtfailadj(n)
         if (tsfact > done) then
           delt_temp = delt / tsfact
           if (delt_temp >= this%dtmin(n)) then
             finishedtrying = .false.
             delt = delt_temp
             write (iout, fmttsi) kstp, kper, delt
           end if
         end if
  
       end if
     end if

◆ ats_set_delt()

subroutine adaptivetimestepmodule::ats_set_delt	(	class(atstype)	this,
		integer(i4b), intent(in)	kstp,
		integer(i4b), intent(in)	kper,
		real(dp), intent(inout)	pertim,
		real(dp), intent(in)	perlencurrent,
		real(dp), intent(inout)	delt
	)

private

Set the time step length (delt) for this time step using the ATS controls.

Definition at line 576 of file ats.f90.

     ! -- modules
     ! -- dummy
     class(AtsType) :: this
     integer(I4B), intent(in) :: kstp
     integer(I4B), intent(in) :: kper
     real(DP), intent(inout) :: pertim
     real(DP), intent(in) :: perlencurrent
     real(DP), intent(inout) :: delt
     ! -- local
     integer(I4B) :: n
     real(DP) :: tstart
     ! -- formats
     character(len=*), parameter :: fmtdt = &
       "(1x, 'ATS: time step set to ', G15.7, ' for step ', i0, &
       &' and period ', i0)"
     !
     ! -- initialize the record position (n) for this stress period
     n = this%kperats(kper)
     !
     ! -- set tstart to the end of the last time step.
     tstart = pertim
     !
     ! -- Calculate delt
     !
     ! -- Setup new stress period if kstp is 1
     if (kstp == 1) then
       !
       ! -- Assign first value of delt for this stress period
       if (this%dt0(n) /= dzero) then
         delt = this%dt0(n)
       else
         ! leave delt the way it was
       end if
     else
       !
       ! -- Assign delt based on stability
       if (this%dtstable /= dnodata) then
         delt = this%dtstable
         this%dtstable = dnodata
       end if
     end if
     !
     ! -- Ensure  tsmin < delt < tsmax
     if (delt < this%dtmin(n)) then
       delt = this%dtmin(n)
     end if
     if (delt > this%dtmax(n)) then
       delt = this%dtmax(n)
     end if
     !
     ! -- Cut timestep down to meet end of period
     if (tstart + delt > perlencurrent - this%dtmin(n)) then
       delt = perlencurrent - tstart
     end if
     !
     ! -- Write time step size information
     write (iout, fmtdt) delt, kstp, kper

◆ ats_set_endofperiod()

subroutine adaptivetimestepmodule::ats_set_endofperiod	(	class(atstype)	this,
		integer(i4b), intent(in)	kper,
		real(dp), intent(inout)	pertim,
		real(dp), intent(in)	perlencurrent,
		logical(lgp), intent(inout)	endofperiod
	)

private

Determine if it is the end of the stress period and set the endofperiod logical variable if so.

Definition at line 684 of file ats.f90.

     ! -- dummy
     class(AtsType) :: this
     integer(I4B), intent(in) :: kper
     real(DP), intent(inout) :: pertim
     real(DP), intent(in) :: perlencurrent
     logical(LGP), intent(inout) :: endofperiod
     ! -- local
     integer(I4B) :: n
     !
     ! -- End of stress period and/or simulation?
     n = this%kperats(kper)
     if (abs(pertim - perlencurrent) < this%dtmin(n)) then
       endofperiod = .true.
     end if

◆ ats_submit_delt()

subroutine adaptivetimestepmodule::ats_submit_delt	(	class(atstype)	this,
		integer(i4b), intent(in)	kstp,
		integer(i4b), intent(in)	kper,
		real(dp), intent(in)	dt,
		character(len=*), intent(in)	sloc,
		integer(i4b), intent(in), optional	idir
	)

private

Submit a preferred time step length. Alternatively, if idir is is passed, then either increase or decrease the submitted time step by the dtadj input variable.

Definition at line 526 of file ats.f90.

     ! -- dummy
     class(AtsType) :: this
     integer(I4B), intent(in) :: kstp
     integer(I4B), intent(in) :: kper
     real(DP), intent(in) :: dt
     character(len=*), intent(in) :: sloc
     integer(I4B), intent(in), optional :: idir
     ! -- local
     integer(I4B) :: n
     real(DP) :: tsfact
     real(DP) :: dt_temp
     character(len=*), parameter :: fmtdtsubmit = &
       &"(1x, 'ATS: ', A,' submitted a preferred time step size of ', G15.7)"
  
     if (this%isAdaptivePeriod(kper)) then
       n = this%kperats(kper)
       tsfact = this%dtadj(n)
       if (tsfact > done) then
         !
         ! -- if idir is present, then dt is a length that should be adjusted
         !    (divided by or multiplied by) by dtadj.  If idir is not present
         !    then dt is the submitted time step.
         if (present(idir)) then
           dt_temp = dzero
           if (idir == -1) then
             dt_temp = dt / tsfact
           else if (idir == 1) then
             dt_temp = dt * tsfact
           end if
         else
           dt_temp = dt
         end if
         if (kstp > 1 .and. dt_temp > dzero) then
           write (iout, fmtdtsubmit) trim(adjustl(sloc)), dt_temp
         end if
         if (dt_temp > dzero .and. dt_temp < this%dtstable) then
           ! -- Reset dtstable to a smaller value
           this%dtstable = dt_temp
         end if
       end if
     end if

◆ isadaptiveperiod()

logical(lgp) function adaptivetimestepmodule::isadaptiveperiod	(	class(atstype)	this,
		integer(i4b), intent(in)	kper
	)

private

Check settings and determine if kper is an adaptive stress period.

Definition at line 58 of file ats.f90.

     class(AtsType) :: this
     integer(I4B), intent(in) :: kper
     logical(LGP) :: lv
     lv = .false.
     if (associated(this%kperats)) then
       if (this%kperats(kper) > 0) then
         lv = .true.
       end if
     end if

Data Types

Functions/Subroutines

Function/Subroutine Documentation

◆ ats_allocate_arrays()

◆ ats_allocate_scalars()

◆ ats_check_timing()

◆ ats_da()

◆ ats_init()

◆ ats_input_table()

◆ ats_period_message()

◆ ats_process_input()

◆ ats_read_dimensions()

◆ ats_read_options()

◆ ats_read_timing()

◆ ats_reset_delt()

◆ ats_set_delt()

◆ ats_set_endofperiod()

◆ ats_submit_delt()

◆ isadaptiveperiod()