---
name: "zdttrsv"
section: "3"
platform: "linux"
package: "scalapack-doc"
version: "1.5-11"
release: "Debian 11 (Bullseye)"
platforms: ["linux"]
url: "https://new.carta.tech/zdttrsv"
---

# zdttrsv(3)

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