---
name: "zsptrs"
section: "3lapack"
platform: "linux"
package: "liblapack-doc"
version: "3.2.1-8"
release: "Debian 6.0 (Squeeze)"
platforms: ["linux"]
url: "https://new.carta.tech/zsptrs/3lapack"
---

# zsptrs(3lapack)

solves a system of linear equations A\*X = B with a complex symmetric matrix A stored in packed format using the factorization A = U\*D\*U\*\*T or A = L\*D\*L\*\*T computed by ZSPTRF

## NAME

ZSPTRS - solves a system of linear equations A\*X = B with a complex symmetric matrix A stored in packed format using the factorization A = U\*D\*U\*\*T or A = L\*D\*L\*\*T computed by ZSPTRF

## SYNOPSIS

- SUBROUTINE ZSPTRS(

  UPLO, N, NRHS, AP, IPIV, B, LDB, INFO )

- CHARACTER

  UPLO

- INTEGER

  INFO, LDB, N, NRHS

- INTEGER

  IPIV( \* )

- COMPLEX\*16

  AP( \* ), B( LDB, \* )

## PURPOSE

ZSPTRS solves a system of linear equations A\*X = B with a complex symmetric matrix A stored in packed format using the factorization A = U\*D\*U\*\*T or A = L\*D\*L\*\*T computed by ZSPTRF.

## ARGUMENTS

- UPLO (input) CHARACTER\*1

  Specifies whether the details of the factorization are stored as an upper or lower triangular matrix. = 'U':  Upper triangular, form is A = U\*D\*U\*\*T;\
   \= 'L':  Lower triangular, form is A = L\*D\*L\*\*T.

- 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.

- AP (input) COMPLEX\*16 array, dimension (N\*(N+1)/2)

  The block diagonal matrix D and the multipliers used to obtain the factor U or L as computed by ZSPTRF, stored as a packed triangular matrix.

- IPIV (input) INTEGER array, dimension (N)

  Details of the interchanges and the block structure of D as determined by ZSPTRF.

- B (input/output) COMPLEX\*16 array, dimension (LDB,NRHS)

  On entry, the right hand side matrix B. On exit, 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