SLATEC Routines --- DGTSL ---

*DECK DGTSL
      SUBROUTINE DGTSL (N, C, D, E, B, INFO)
C***BEGIN PROLOGUE  DGTSL
C***PURPOSE  Solve a tridiagonal linear system.
C***LIBRARY   SLATEC (LINPACK)
C***CATEGORY  D2A2A
C***TYPE      DOUBLE PRECISION (SGTSL-S, DGTSL-D, CGTSL-C)
C***KEYWORDS  LINEAR ALGEBRA, LINPACK, MATRIX, SOLVE, TRIDIAGONAL
C***AUTHOR  Dongarra, J., (ANL)
C***DESCRIPTION
C
C     DGTSL given a general tridiagonal matrix and a right hand
C     side will find the solution.
C
C     On Entry
C
C        N       INTEGER
C                is the order of the tridiagonal matrix.
C
C        C       DOUBLE PRECISION(N)
C                is the subdiagonal of the tridiagonal matrix.
C                C(2) through C(N) should contain the subdiagonal.
C                On output C is destroyed.
C
C        D       DOUBLE PRECISION(N)
C                is the diagonal of the tridiagonal matrix.
C                On output D is destroyed.
C
C        E       DOUBLE PRECISION(N)
C                is the superdiagonal of the tridiagonal matrix.
C                E(1) through E(N-1) should contain the superdiagonal.
C                On output E is destroyed.
C
C        B       DOUBLE PRECISION(N)
C                is the right hand side vector.
C
C     On Return
C
C        B       is the solution vector.
C
C        INFO    INTEGER
C                = 0 normal value.
C                = K if the K-th element of the diagonal becomes
C                    exactly zero.  The subroutine returns when
C                    this is detected.
C
C***REFERENCES  J. J. Dongarra, J. R. Bunch, C. B. Moler, and G. W.
C                 Stewart, LINPACK Users' Guide, SIAM, 1979.
C***ROUTINES CALLED  (NONE)
C***REVISION HISTORY  (YYMMDD)
C   780814  DATE WRITTEN
C   890531  Changed all specific intrinsics to generic.  (WRB)
C   890831  Modified array declarations.  (WRB)
C   890831  REVISION DATE from Version 3.2
C   891214  Prologue converted to Version 4.0 format.  (BAB)
C   900326  Removed duplicate information from DESCRIPTION section.
C           (WRB)
C   920501  Reformatted the REFERENCES section.  (WRB)
C***END PROLOGUE  DGTSL