# chetrs_rook.f man page

chetrs_rook.f —

## Synopsis

### Functions/Subroutines

subroutinechetrs_rook(UPLO, N, NRHS, A, LDA, IPIV, B, LDB, INFO)CHETRS_ROOKcomputes the solution to a system of linear equations A * X = B for HE matrices using factorization obtained with one of the bounded diagonal pivoting methods (max 2 interchanges)

## Function/Subroutine Documentation

### subroutine chetrs_rook (characterUPLO, integerN, integerNRHS, complex, dimension( lda, * )A, integerLDA, integer, dimension( * )IPIV, complex, dimension( ldb, * )B, integerLDB, integerINFO)

**CHETRS_ROOK** computes the solution to a system of linear equations A * X = B for HE matrices using factorization obtained with one of the bounded diagonal pivoting methods (max 2 interchanges)

**Purpose:**

```
CHETRS_ROOK solves a system of linear equations A*X = B with a complex
Hermitian matrix A using the factorization A = U*D*U**H or
A = L*D*L**H computed by CHETRF_ROOK.
```

**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**H;
= 'L': Lower triangular, form is A = L*D*L**H.
```

*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 CHETRF_ROOK.
```

*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 CHETRF_ROOK.
```

*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).
```

*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

Univ. of Colorado Denver

NAG Ltd.

**Date:**

November 2013

**Contributors:**

```
November 2013, Igor Kozachenko,
Computer Science Division,
University of California, Berkeley
September 2007, Sven Hammarling, Nicholas J. Higham, Craig Lucas,
School of Mathematics,
University of Manchester
```

Definition at line 136 of file chetrs_rook.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

chetrs_rook(3) is an alias of chetrs_rook.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK