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 equationsA*X = B or A'*X = B, with a tridiagonal matrix A using the LU factorization 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 (N1)
 The (n1) 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 (N1)
 The (n1) elements of the first superdiagonal of U.
 DU2 (input) REAL array, dimension (N2)
 The (n2) elements of the second superdiagonal 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) will always be either i or i+1; IPIV(i) = i indicates 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).