hetf2_rook

chetf2_rook

Functions

void chetf2_rook(
    const char*          uplo,
    const INT            n,
          c64*  restrict A,
    const INT            lda,
          INT*  restrict ipiv,
          INT*           info
);

void chetf2_rook(const char *uplo, const INT n, c64 *restrict A, const INT lda, INT *restrict ipiv, INT *info)

CHETF2_ROOK computes the factorization of a complex Hermitian matrix A using the bounded Bunch-Kaufman (“rook”) diagonal pivoting method:

A = U*D*U**H or A = L*D*L**H

where U (or L) is a product of permutation and unit upper (lower) triangular matrices, U**H is the conjugate transpose of U, and D is Hermitian and block diagonal with 1-by-1 and 2-by-2 diagonal blocks.

This is the unblocked version of the algorithm, calling Level 2 BLAS.

Parameters

in

uplo

= ‘U’: Upper triangular = ‘L’: Lower triangular

in

n

The order of the matrix A. n >= 0.

inout

A

Single complex array, dimension (lda, n). On entry, the Hermitian matrix A. On exit, the block diagonal matrix D and the multipliers.

in

lda

The leading dimension of A. lda >= max(1, n).

out

ipiv

Integer array, dimension (n). Details of the interchanges and block structure.

out

info

• = 0: successful exit

• < 0: if info = -k, the k-th argument had an illegal value

• > 0: if info = k, D(k,k) is exactly zero.

zhetf2_rook

Functions

void zhetf2_rook(
    const char*          uplo,
    const INT            n,
          c128* restrict A,
    const INT            lda,
          INT*  restrict ipiv,
          INT*           info
);

void zhetf2_rook(const char *uplo, const INT n, c128 *restrict A, const INT lda, INT *restrict ipiv, INT *info)

ZHETF2_ROOK computes the factorization of a complex Hermitian matrix A using the bounded Bunch-Kaufman (“rook”) diagonal pivoting method:

A = U*D*U**H or A = L*D*L**H

where U (or L) is a product of permutation and unit upper (lower) triangular matrices, U**H is the conjugate transpose of U, and D is Hermitian and block diagonal with 1-by-1 and 2-by-2 diagonal blocks.

This is the unblocked version of the algorithm, calling Level 2 BLAS.

Parameters

in

uplo

= ‘U’: Upper triangular = ‘L’: Lower triangular

in

n

The order of the matrix A. n >= 0.

inout

A

Double complex array, dimension (lda, n). On entry, the Hermitian matrix A. On exit, the block diagonal matrix D and the multipliers.

in

lda

The leading dimension of A. lda >= max(1, n).

out

ipiv

Integer array, dimension (n). Details of the interchanges and block structure.

out

info

• = 0: successful exit

• < 0: if info = -k, the k-th argument had an illegal value

• > 0: if info = k, D(k,k) is exactly zero.