dptsl.f

      SUBROUTINE DPTSL (N, D, E, B)
C***BEGIN PROLOGUE  DPTSL
C***PURPOSE  Solve a positive definite tridiagonal linear system.
C***LIBRARY   SLATEC (LINPACK)
C***CATEGORY  D2B2A
C***TYPE      DOUBLE PRECISION (SPTSL-S, DPTSL-D, CPTSL-C)
C***KEYWORDS  LINEAR ALGEBRA, LINPACK, MATRIX, POSITIVE DEFINITE, SOLVE,
C             TRIDIAGONAL
C***AUTHOR  Dongarra, J., (ANL)
C***DESCRIPTION
C
C     DPTSL, given a positive definite symmetric tridiagonal matrix and
C     a right hand side, will find the solution.
C
C     On Entry
C
C        N        INTEGER
C                 is the order of the tridiagonal matrix.
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 offdiagonal of the tridiagonal matrix.
C                 E(1) through E(N-1) should contain the
C                 offdiagonal.
C
C        B        DOUBLE PRECISION(N)
C                 is the right hand side vector.
C
C     On Return
C
C        B        contains the solution.
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   890505  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  DPTSL