Provided by: scalapack-doc_1.5-10_all #### NAME

```       CDTTRSV - solve one of the systems of equations  L * X = B, L**T * X = B, or L**H * X = B,

```

#### SYNOPSIS

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

CHARACTER       UPLO, TRANS

INTEGER         INFO, LDB, N, NRHS

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

```

#### PURPOSE

```       CDTTRSV 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 CDTTRF.

```

#### 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
```