SLATEC Routines --- DDNTL ---

*DECK DDNTL
      SUBROUTINE DDNTL (EPS, F, FA, HMAX, HOLD, IMPL, JTASK, MATDIM,
     8   MAXORD, MINT, MITER, ML, MU, N, NDE, SAVE1, T, UROUND, USERS,
     8   Y, YWT, H, MNTOLD, MTROLD, NFE, RC, YH, A, CONVRG, EL, FAC,
     8   IER, IPVT, NQ, NWAIT, RH, RMAX, SAVE2, TQ, TREND, ISWFLG,
     8   JSTATE)
C***BEGIN PROLOGUE  DDNTL
C***SUBSIDIARY
C***PURPOSE  Subroutine DDNTL is called to set parameters on the first
C            call to DDSTP, on an internal restart, or when the user has
C            altered MINT, MITER, and/or H.
C***LIBRARY   SLATEC (SDRIVE)
C***TYPE      DOUBLE PRECISION (SDNTL-S, DDNTL-D, CDNTL-C)
C***AUTHOR  Kahaner, D. K., (NIST)
C             National Institute of Standards and Technology
C             Gaithersburg, MD  20899
C           Sutherland, C. D., (LANL)
C             Mail Stop D466
C             Los Alamos National Laboratory
C             Los Alamos, NM  87545
C***DESCRIPTION
C
C  On the first call, the order is set to 1 and the initial derivatives
C  are calculated.  RMAX is the maximum ratio by which H can be
C  increased in one step.  It is initially RMINIT to compensate
C  for the small initial H, but then is normally equal to RMNORM.
C  If a failure occurs (in corrector convergence or error test), RMAX
C  is set at RMFAIL for the next increase.
C  If the caller has changed MINT, or if JTASK = 0, DDCST is called
C  to set the coefficients of the method.  If the caller has changed H,
C  YH must be rescaled.  If H or MINT has been changed, NWAIT is
C  reset to NQ + 2 to prevent further increases in H for that many
C  steps.  Also, RC is reset.  RC is the ratio of new to old values of
C  the coefficient L(0)*H.  If the caller has changed MITER, RC is
C  set to 0 to force the partials to be updated, if partials are used.
C
C***ROUTINES CALLED  DDCST, DDSCL, DGBFA, DGBSL, DGEFA, DGESL, DNRM2
C***REVISION HISTORY  (YYMMDD)
C   790601  DATE WRITTEN
C   900329  Initial submission to SLATEC.
C***END PROLOGUE  DDNTL