dpkset Subroutine

subroutine dpkset(Neq, Y, Ysv, Ewt, Ftem, Savf, Wm, Iwm, f, jac)

DPKSET is called by DSTODPK to interface with the user-supplied routine JAC, to compute and process relevant parts of the matrix P = I - HEL(1)J, where J is the Jacobian df/dy, as need for preconditioning matrix operations later.

In addition to variables described previously, communication with DPKSET uses the following:

Y

array containing predicted values on entry.

YSV

array containing predicted y, to be saved (YH1 in DSTODPK).

FTEM

work array of length N (ACOR in DSTODPK).

SAVF

array containing f evaluated at predicted y.

WM

real work space for matrices. Space for preconditioning data starts at WM(LOCWP).

IWM

integer work space. Space for preconditioning data starts at IWM(LOCIWP).

IERPJ

output error flag, = 0 if no trouble, .gt. 0 if JAC returned an error flag.

JCUR

output flag = 1 to indicate that the Jacobian matrix (or approximation) is now current.

This routine also uses Common variables EL0, H, TN, IERPJ, JCUR, NJE.

Arguments

subroutine dpkset(Neq,Y,Ysv,Ewt,Ftem,Savf,Wm,Iwm,f,jac)

integer       :: Neq(*)
real(kind=dp) :: Y(*)
real(kind=dp) :: Ysv(*)
real(kind=dp) :: Ewt(*)
real(kind=dp) :: Ftem(*)
real(kind=dp) :: Savf(*)
real(kind=dp) :: Wm(*)
integer       :: Iwm(*)
external      :: f
external      :: jac

real(kind=dp) :: hl0
integer       :: ier

   dls1%ierpj = 0
   dls1%jcur = 1
   hl0 = dls1%el0*dls1%h
   call jac(f,Neq,dls1%tn,Y,Ysv,Ewt,Savf,Ftem,hl0,Wm(dlpk%locwp),Iwm(dlpk%lociwp),ier)
   dls1%nje = dls1%nje + 1

   if ( ier /= 0 )then
      dls1%ierpj = 1
   endif

end subroutine dpkset