ddaslv.f

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      SUBROUTINE ddaslv (NEQ, DELTA, WM, IWM)
C***BEGIN PROLOGUE  DDASLV
C***SUBSIDIARY
C***PURPOSE  Linear system solver for DDASSL.
C***LIBRARY   SLATEC (DASSL)
C***TYPE      DOUBLE PRECISION (SDASLV-S, DDASLV-D)
C***AUTHOR  PETZOLD, LINDA R., (LLNL)
C***DESCRIPTION
C-----------------------------------------------------------------------
C     THIS ROUTINE MANAGES THE SOLUTION OF THE LINEAR
C     SYSTEM ARISING IN THE NEWTON ITERATION.
C     MATRICES AND REAL TEMPORARY STORAGE AND
C     REAL INFORMATION ARE STORED IN THE ARRAY WM.
C     INTEGER MATRIX INFORMATION IS STORED IN
C     THE ARRAY IWM.
C     FOR A DENSE MATRIX, THE LAPACK ROUTINE
C     DGETRS IS CALLED.
C     FOR A BANDED MATRIX,THE LAPACK ROUTINE
C     DGBTRS IS CALLED.
C-----------------------------------------------------------------------
C***ROUTINES CALLED  DGBTRS, DGETRF
C***REVISION HISTORY  (YYMMDD)
C   830315  DATE WRITTEN
C   901009  Finished conversion to SLATEC 4.0 format (F.N.Fritsch)
C   901019  Merged changes made by C. Ulrich with SLATEC 4.0 format.
C   901026  Added explicit declarations for all variables and minor
C           cosmetic changes to prologue.  (FNF)
C   020204  Convert to use LAPACK
C***END PROLOGUE  DDASLV
C
      INTEGER  neq, iwm(*)
      DOUBLE PRECISION  delta(*), wm(*)
C
      EXTERNAL  dgbtrs, dgetrs
C
      INTEGER  lipvt, lml, lmu, lmtype, meband, mtype, npd, info
      parameter(npd=1)
      parameter(lml=1)
      parameter(lmu=2)
      parameter(lmtype=4)
      parameter(lipvt=22)
C
C***FIRST EXECUTABLE STATEMENT  DDASLV
      mtype=iwm(lmtype)
      go to(100,100,300,400,400),mtype
C
C     DENSE MATRIX
100   CALL dgetrs('N', neq, 1, wm(npd), neq, iwm(lipvt), delta, neq, 
     *     info)
      RETURN
C
C     DUMMY SECTION FOR MTYPE=3
300   CONTINUE
      RETURN
C
C     BANDED MATRIX
400   meband=2*iwm(lml)+iwm(lmu)+1
      CALL dgbtrs('N', neq, iwm(lml), iwm(lmu), 1, wm(npd), meband, 
     *     iwm(lipvt), delta, neq, inlpck)
      RETURN
C------END OF SUBROUTINE DDASLV------
      END