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# zdttrsv

## man page of zdttrsv

### zdttrsv: solve one of the systems of equations L * X = B, L**T * X = B, or L**H * X = B,

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

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

CHARACTER       UPLO, TRANS

INTEGER         INFO, LDB, N, NRHS

COMPLEX*16      B( LDB, * ), D( * ), DL( * ), DU( * )

PURPOSE
ZDTTRSV 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 ZDTTRF.

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

ZDTTRSV(3)
```