 SDTTRSV(1) solve one of the systems of equations L * X = B, L**T * X = B, or L**H * X = B,

## SYNOPSIS

SUBROUTINE SDTTRSV(
UPLO, TRANS, N, NRHS, DL, D, DU, B, LDB, INFO )

CHARACTER UPLO, TRANS

INTEGER INFO, LDB, N, NRHS

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

## PURPOSE

SDTTRSV solves one of the systems of equations
L * X = B,  L**T * X = B,  or  L**H * X = B,
U * X = B,  U**T * X = B,  or  U**H * X = B,
with factors of the tridiagonal matrix A from the LU factorization computed by SDTTRF.

## ARGUMENTS

UPLO (input) CHARACTER*1
Specifies whether to solve with L or U.
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. N >= 0.
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 superdiagonal of U.
B (input/output) COMPLEX array, dimension (LDB,NRHS)
On entry, the right hand side matrix B. On exit, B is overwritten by the solution matrix X.
LDB (input) INTEGER
The leading dimension of the array B. LDB >= max(1,N).
INFO (output) INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value