share/odepack/fortran/dpkset.f

   1 *DECK DPKSET
   2       SUBROUTINE DPKSET (NEQ, Y, YSV, EWT, FTEM, SAVF, WM, IWM, F, JAC)
   3       EXTERNAL F, JAC
   4       INTEGER NEQ, IWM
   5       DOUBLE PRECISION Y, YSV, EWT, FTEM, SAVF, WM
   6       DIMENSION NEQ(*), Y(*), YSV(*), EWT(*), FTEM(*), SAVF(*),
   7      1   WM(*), IWM(*)
   8       INTEGER IOWND, IOWNS,
   9      1   ICF, IERPJ, IERSL, JCUR, JSTART, KFLAG, L,
  10      2   LYH, LEWT, LACOR, LSAVF, LWM, LIWM, METH, MITER,
  11      3   MAXORD, MAXCOR, MSBP, MXNCF, N, NQ, NST, NFE, NJE, NQU
  12       INTEGER JPRE, JACFLG, LOCWP, LOCIWP, LSAVX, KMP, MAXL, MNEWT,
  13      1   NNI, NLI, NPS, NCFN, NCFL
  14       DOUBLE PRECISION ROWNS,
  15      1   CCMAX, EL0, H, HMIN, HMXI, HU, RC, TN, UROUND
  16       DOUBLE PRECISION DELT, EPCON, SQRTN, RSQRTN
  17       COMMON /DLS001/ ROWNS(209),
  18      1   CCMAX, EL0, H, HMIN, HMXI, HU, RC, TN, UROUND,
  19      2   IOWND(6), IOWNS(6),
  20      3   ICF, IERPJ, IERSL, JCUR, JSTART, KFLAG, L,
  21      4   LYH, LEWT, LACOR, LSAVF, LWM, LIWM, METH, MITER,
  22      5   MAXORD, MAXCOR, MSBP, MXNCF, N, NQ, NST, NFE, NJE, NQU
  23       COMMON /DLPK01/ DELT, EPCON, SQRTN, RSQRTN,
  24      1   JPRE, JACFLG, LOCWP, LOCIWP, LSAVX, KMP, MAXL, MNEWT,
  25      2   NNI, NLI, NPS, NCFN, NCFL
  26 C-----------------------------------------------------------------------
  27 C DPKSET is called by DSTODPK to interface with the user-supplied
  28 C routine JAC, to compute and process relevant parts of
  29 C the matrix P = I - H*EL(1)*J , where J is the Jacobian df/dy,
  30 C as need for preconditioning matrix operations later.
  31 C
  32 C In addition to variables described previously, communication
  33 C with DPKSET uses the following:
  34 C Y     = array containing predicted values on entry.
  35 C YSV   = array containing predicted y, to be saved (YH1 in DSTODPK).
  36 C FTEM  = work array of length N (ACOR in DSTODPK).
  37 C SAVF  = array containing f evaluated at predicted y.
  38 C WM    = real work space for matrices.
  39 C         Space for preconditioning data starts at WM(LOCWP).
  40 C IWM   = integer work space.
  41 C         Space for preconditioning data starts at IWM(LOCIWP).
  42 C IERPJ = output error flag,  = 0 if no trouble, .gt. 0 if
  43 C         JAC returned an error flag.
  44 C JCUR  = output flag = 1 to indicate that the Jacobian matrix
  45 C         (or approximation) is now current.
  46 C This routine also uses Common variables EL0, H, TN, IERPJ, JCUR, NJE.
  47 C-----------------------------------------------------------------------
  48       INTEGER IER
  49       DOUBLE PRECISION HL0
  50 C
  51       IERPJ = 0
  52       JCUR = 1
  53       HL0 = EL0*H
  54       CALL JAC (F, NEQ, TN, Y, YSV, EWT, SAVF, FTEM, HL0,
  55      1   WM(LOCWP), IWM(LOCIWP), IER)
  56       NJE = NJE + 1
  57       IF (IER .EQ. 0) RETURN
  58       IERPJ = 1
  59       RETURN
  60 C----------------------- End of Subroutine DPKSET ----------------------
  61       END