SDASSL

      SUBROUTINE SDASSL (RES,NEQ,T,Y,YPRIME,TOUT,
     *  INFO,RTOL,ATOL,IDID,
     *  RWORK,LRW,IWORK,LIW,RPAR,IPAR,
     *  JAC)
C
C***BEGIN PROLOGUE  SDASSL
C***DATE WRITTEN   830315   (YYMMDD)
C***REVISION DATE  830315   (YYMMDD)
C***CATEGORY NO.  D2A2
C***KEYWORDS  DIFFERENTIAL/ALGEBRAIC,BACKWARD DIFFERENTIATION FORMULAS
C             IMPLICIT DIFFERENTIAL SYSTEMS
C***AUTHOR  PETZOLD,LINDA R.,APPLIED MATH DIV,SANDIA NAT LAB,LIVERMORE CA. 94550
C***PURPOSE  DIFFERENTIAL/ALGEBRAIC SYSTEM SOLVER
C***DESCRIPTION
C  ---------------------------------------------------------------------
C
C  this code solves a system of differential/
C  algebraic equations of the form
C  g(t,y,yprime) = 0.
C
C  subroutine sdassl uses the backward
C  differentiation formulas of orders one
C  through five to solve a system of the above
C  form for y and yprime. values for y
C  and yprime at the initial time must
C  be given as input. these values must
C  be consistent, (that is. if t,y,yprime
C  are the given initial values, they must
C  satisfy g(t,y,yprime) = 0.)
C  the subroutine solves the system from t to tout. it is
C  easy to continue the solution to get results
C  at additional tout. this is the interval
C  mode of operation. intermediate results can
C  also be obtained easily by using the intermediate-
C  output capability.
C
C***REFERENCES  A DESCRIPTION OF DASSL: A DIFFERENTIAL/ALGEBRAIC
C                  SYSTEM SOLVER, L. R. PETZOLD, SAND82-8637,
C                  SANDIA NATIONAL LABORATORIES, SEPTEMBER 1982.
C***ROUTINES CALLED  R1MACH,SDASTP,SDAINI,SDANRM,SDAWTS,SDATRP,XERRWV
C***COMMON BLOCKS    SDA001
C***END PROLOGUE  SDASSL