dprep Subroutine

subroutine dprep(Neq, Y, Yh, Savf, Ewt, Ftem, Ia, Ja, Wk, Iwk, Ipper, f, jac)

Uses

  • proc~~dprep~~UsesGraph proc~dprep M_odepack.f90::dprep module~m_odepack M_odepack proc~dprep->module~m_odepack

This routine performs preprocessing related to the sparse linear systems that must be solved if MITER = 1 or 2.

The operations that are performed here are:

  • compute sparseness structure of Jacobian according to MOSS,
  • compute grouping of column indices (MITER = 2),
  • compute a new ordering of rows and columns of the matrix,
  • reorder JA corresponding to the new ordering,
  • perform a symbolic LU factorization of the matrix, and
  • set pointers for segments of the IWK/WK array.

In addition to variables described previously, DPREP uses the following for communication:

YH

the history array. Only the first column, containing the current Y vector, is used. Used only if MOSS .ne. 0.

SAVF

a work array of length NEQ, used only if MOSS .ne. 0.

EWT

array of length NEQ containing (inverted) error weights. Used only if MOSS = 2 or if ISTATE = MOSS = 1.

FTEM

a work array of length NEQ, identical to ACOR in the driver, used only if MOSS = 2.

WK

a real work array of length LENWK, identical to WM in the driver.

IWK

integer work array, assumed to occupy the same space as WK.

LENWK

the length of the work arrays WK and IWK.

ISTATC

a copy of the driver input argument ISTATE (= 1 on the first call, = 3 on a continuation call).

IYS

flag value from ODRV or CDRV.

IPPER

output error flag with the following values and meanings: 0 no error. -1 insufficient storage for internal structure pointers. -2 insufficient storage for JGROUP. -3 insufficient storage for ODRV. -4 other error flag from ODRV (should never occur). -5 insufficient storage for CDRV. -6 other error flag from CDRV.

Arguments

Type IntentOptional Attributes Name
integer :: Neq(*)
real(kind=dp), intent(inout) :: Y(*)
real(kind=dp), intent(in) :: Yh(*)
real(kind=dp), intent(inout) :: Savf(*)
real(kind=dp), intent(in) :: Ewt(*)
real(kind=dp) :: Ftem(*)
integer, intent(in) :: Ia(*)
integer, intent(in) :: Ja(*)
real(kind=dp) :: Wk(*)
integer, intent(inout) :: Iwk(*)
integer, intent(out) :: Ipper
real :: f
integer :: jac

Calls

proc~~dprep~~CallsGraph proc~dprep M_odepack.f90::dprep none~wrapup400 dprep::wrapup400 proc~dprep->none~wrapup400 none~wrapup500 dprep::wrapup500 proc~dprep->none~wrapup500 none~wrapup600 dprep::wrapup600 proc~dprep->none~wrapup600 none~wrapup700 dprep::wrapup700 proc~dprep->none~wrapup700 proc~adjlr~2 M_odepack::adjlr proc~dprep->proc~adjlr~2 proc~cdrv M_odepack::cdrv proc~dprep->proc~cdrv proc~jgroup M_odepack::jgroup proc~dprep->proc~jgroup proc~odrv~2 M_odepack::odrv proc~dprep->proc~odrv~2 proc~cntnzu~2 M_odepack::cntnzu none~wrapup600->proc~cntnzu~2

Variables

Type Visibility Attributes Name Initial
integer, public, parameter :: dp = kind(0.0d0)
real(kind=dp), public :: dq
real(kind=dp), public :: dyj
real(kind=dp), public :: erwt
real(kind=dp), public :: fac
integer, public :: i
integer, public :: ibr
integer, public :: ier
integer, public :: ipil
integer, public :: ipiu
integer, public :: iptt1
integer, public :: iptt2
integer, public :: j
integer, public :: jfound
integer, public :: k
integer, public :: kmax
integer, public :: kmin
integer, public :: knew
integer, public :: ldif
integer, public :: lenigp
integer, public :: liwk
integer, public :: maxg
integer, public :: np1
integer, public :: nzsut
real(kind=dp), public :: yj

Subroutines

subroutine wrapup400()

Arguments

None

subroutine wrapup500()

Arguments

None

subroutine wrapup600()

Arguments

None

subroutine wrapup700()

Arguments

None