# csytrs2.f - Man Page

SRC/csytrs2.f

## Synopsis

### Functions/Subroutines

subroutine csytrs2 (uplo, n, nrhs, a, lda, ipiv, b, ldb, work, info)
CSYTRS2

## Function/Subroutine Documentation

### subroutine csytrs2 (character uplo, integer n, integer nrhs, complex, dimension( lda, * ) a, integer lda, integer, dimension( * ) ipiv, complex, dimension( ldb, * ) b, integer ldb, complex, dimension( * ) work, integer info)

CSYTRS2

Purpose:

``` CSYTRS2 solves a system of linear equations A*X = B with a complex
symmetric matrix A using the factorization A = U*D*U**T or
A = L*D*L**T computed by CSYTRF and converted by CSYCONV.```
Parameters

UPLO

```          UPLO is 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

```          N is INTEGER
The order of the matrix A.  N >= 0.```

NRHS

```          NRHS is INTEGER
The number of right hand sides, i.e., the number of columns
of the matrix B.  NRHS >= 0.```

A

```          A is COMPLEX array, dimension (LDA,N)
The block diagonal matrix D and the multipliers used to
obtain the factor U or L as computed by CSYTRF.
Note that A is input / output. This might be counter-intuitive,
and one may think that A is input only. A is input / output. This
is because, at the start of the subroutine, we permute A in a
'better' form and then we permute A back to its original form at
the end.```

LDA

```          LDA is INTEGER
The leading dimension of the array A.  LDA >= max(1,N).```

IPIV

```          IPIV is INTEGER array, dimension (N)
Details of the interchanges and the block structure of D
as determined by CSYTRF.```

B

```          B is COMPLEX array, dimension (LDB,NRHS)
On entry, the right hand side matrix B.
On exit, the solution matrix X.```

LDB

```          LDB is INTEGER
The leading dimension of the array B.  LDB >= max(1,N).```

WORK

`          WORK is COMPLEX array, dimension (N)`

INFO

```          INFO is INTEGER
= 0:  successful exit
< 0:  if INFO = -i, the i-th argument had an illegal value```
Author

Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Definition at line 130 of file csytrs2.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page csytrs2(3) is an alias of csytrs2.f(3).

Tue Nov 28 2023 12:08:41 Version 3.12.0 LAPACK