SGTTS2  - solve one of the systems of equations A*X = B or
       A'*X = B,


SYNOPSIS

       SUBROUTINE SGTTS2( ITRANS, N, NRHS, DL, D, DU, DU2,  IPIV,
                          B, LDB )

           INTEGER        ITRANS, LDB, N, NRHS

           INTEGER        IPIV( * )

           REAL           B(  LDB, * ), D( * ), DL( * ), DU( * ),
                          DU2( * )


PURPOSE

       SGTTS2 solves one of the systems of equations A*X =  B  or
       A'*X = B, with a tridiagonal matrix A using the LU factor­
       ization computed by SGTTRF.


ARGUMENTS

       ITRANS  (input) INTEGER
               Specifies the form of the system of equations.   =
               0:  A * X = B  (No transpose)
               = 1:  A'* X = B  (Transpose)
               = 2:  A'* X = B  (Conjugate transpose = Transpose)

       N       (input) INTEGER
               The order of the matrix A.

       NRHS    (input) INTEGER
               The number of right hand sides, i.e.,  the  number
               of columns of the matrix B.  NRHS >= 0.

       DL      (input) REAL array, dimension (N-1)
               The  (n-1)  multipliers  that  define the matrix L
               from the LU factorization of A.

       D       (input) REAL array, dimension (N)
               The n diagonal elements of  the  upper  triangular
               matrix U from the LU factorization of A.

       DU      (input) REAL array, dimension (N-1)
               The  (n-1) elements of the first super-diagonal of
               U.

       DU2     (input) REAL array, dimension (N-2)
               The (n-2) elements of the second super-diagonal of
               U.

       IPIV    (input) INTEGER array, dimension (N)
               The  pivot  indices; for 1 <= i <= n, row i of the
               matrix was interchanged with row IPIV(i).  IPIV(i)

               cates a row interchange was not required.

       B       (input/output) REAL array, dimension (LDB,NRHS)
               On entry, the matrix of right hand side vectors B.
               On  exit, B is overwritten by the solution vectors
               X.

       LDB     (input) INTEGER
               The leading dimension of  the  array  B.   LDB  >=
               max(1,N).


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