CGTTRS  - solve one of the systems of equations A * X = B,
       A**T * X = B, or A**H * X = B,


SYNOPSIS

       SUBROUTINE CGTTRS( TRANS, N, NRHS, DL, D, DU,  DU2,  IPIV,
                          B, LDB, INFO )

           CHARACTER      TRANS

           INTEGER        INFO, LDB, N, NRHS

           INTEGER        IPIV( * )

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


PURPOSE

       CGTTRS solves one of the systems of equations A * X  =  B,
       A**T * X = B, or A**H * X = B, with a tridiagonal matrix A
       using the LU factorization computed by CGTTRF.


ARGUMENTS

       TRANS   (input) CHARACTER
               Specifies the form of the system of equations.   =
               'N':  A * X = B     (No transpose)
               = 'T':  A**T * X = B  (Transpose)
               = 'C':  A**H * X = B  (Conjugate 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) COMPLEX array, dimension (N-1)
               The (n-1) multipliers that  define  the  matrix  L
               from the LU factorization of A.

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

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

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

               The pivot indices; for 1 <= i <= n, row i  of  the
               matrix was interchanged with row IPIV(i).  IPIV(i)
               will always be either i or i+1; IPIV(i) = i  indi­
               cates a row interchange was not required.

       B       (input/output) COMPLEX 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).

       INFO    (output) INTEGER
               = 0:  successful exit
               < 0:  if INFO = -k, the k-th argument had an ille­
               gal value


Man(1) output converted with man2html