# chetrs_aa_2stage.f - Man Page

SRC/chetrs_aa_2stage.f

## Synopsis

### Functions/Subroutines

subroutine **chetrs_aa_2stage** (uplo, n, nrhs, a, lda, tb, ltb, ipiv, ipiv2, b, ldb, info)**CHETRS_AA_2STAGE**

## Function/Subroutine Documentation

### subroutine chetrs_aa_2stage (character uplo, integer n, integer nrhs, complex, dimension( lda, * ) a, integer lda, complex, dimension( * ) tb, integer ltb, integer, dimension( * ) ipiv, integer, dimension( * ) ipiv2, complex, dimension( ldb, * ) b, integer ldb, integer info)

**CHETRS_AA_2STAGE** Ā

**Purpose:**

CHETRS_AA_2STAGE solves a system of linear equations A*X = B with a real hermitian matrix A using the factorization A = U**T*T*U or A = L*T*L**T computed by CHETRF_AA_2STAGE.

**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**T*T*U; = 'L': Lower triangular, form is A = L*T*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) Details of factors computed by CHETRF_AA_2STAGE.

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

*TB*TB is COMPLEX array, dimension (LTB) Details of factors computed by CHETRF_AA_2STAGE.

*LTB*LTB is INTEGER The size of the array TB. LTB >= 4*N.

*IPIV*IPIV is INTEGER array, dimension (N) Details of the interchanges as computed by CHETRF_AA_2STAGE.

*IPIV2*IPIV2 is INTEGER array, dimension (N) Details of the interchanges as computed by CHETRF_AA_2STAGE.

*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.

Definition at line **139** of file **chetrs_aa_2stage.f**.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page chetrs_aa_2stage(3) is an alias of chetrs_aa_2stage.f(3).

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