hegs2#

chegs2

Functions

void chegs2(
    const INT            itype,
    const char*          uplo,
    const INT            n,
          c64*  restrict A,
    const INT            lda,
          c64*  restrict B,
    const INT            ldb,
          INT*           info
);

void chegs2(const INT itype, const char *uplo, const INT n, c64 *restrict A, const INT lda, c64 *restrict B, const INT ldb, INT *info)#

CHEGS2 reduces a complex Hermitian-definite generalized eigenproblem to standard form.

If ITYPE = 1, the problem is A*x = lambda*B*x, and A is overwritten by inv(U**H)*A*inv(U) or inv(L)*A*inv(L**H)

If ITYPE = 2 or 3, the problem is A*B*x = lambda*x or B*A*x = lambda*x, and A is overwritten by U*A*U**H or L**H *A*L.

B must have been previously factorized as U**H *U or L*L**H by CPOTRF.

Parameters

in

itype

= 1: compute inv(U**H)*A*inv(U) or inv(L)*A*inv(L**H); = 2 or 3: compute U*A*U**H or L**H *A*L.

in

uplo

Specifies whether the upper or lower triangular part of the Hermitian matrix A is stored, and how B has been factorized. = ‘U’: Upper triangular = ‘L’: Lower triangular

in

n

The order of the matrices A and B. N >= 0.

inout

A

Complex*16 array, dimension (LDA,N). On entry, the Hermitian matrix A. If UPLO = ‘U’, the leading n by n upper triangular part of A contains the upper triangular part of the matrix A, and the strictly lower triangular part of A is not referenced. If UPLO = ‘L’, the leading n by n lower triangular part of A contains the lower triangular part of the matrix A, and the strictly upper triangular part of A is not referenced. On exit, if INFO = 0, the transformed matrix, stored in the same format as A.

in

lda

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

inout

B

Complex*16 array, dimension (LDB,N). The triangular factor from the Cholesky factorization of B, as returned by CPOTRF. B is modified by the routine but restored on exit.

in

ldb

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

out

info

= 0: successful exit. < 0: if INFO = -i, the i-th argument had an illegal value.

zhegs2

Functions

void zhegs2(
    const INT            itype,
    const char*          uplo,
    const INT            n,
          c128* restrict A,
    const INT            lda,
          c128* restrict B,
    const INT            ldb,
          INT*           info
);

void zhegs2(const INT itype, const char *uplo, const INT n, c128 *restrict A, const INT lda, c128 *restrict B, const INT ldb, INT *info)#

ZHEGS2 reduces a complex Hermitian-definite generalized eigenproblem to standard form.

If ITYPE = 1, the problem is A*x = lambda*B*x, and A is overwritten by inv(U**H)*A*inv(U) or inv(L)*A*inv(L**H)

If ITYPE = 2 or 3, the problem is A*B*x = lambda*x or B*A*x = lambda*x, and A is overwritten by U*A*U**H or L**H *A*L.

B must have been previously factorized as U**H *U or L*L**H by ZPOTRF.

Parameters

in

itype

= 1: compute inv(U**H)*A*inv(U) or inv(L)*A*inv(L**H); = 2 or 3: compute U*A*U**H or L**H *A*L.

in

uplo

Specifies whether the upper or lower triangular part of the Hermitian matrix A is stored, and how B has been factorized. = ‘U’: Upper triangular = ‘L’: Lower triangular

in

n

The order of the matrices A and B. N >= 0.

inout

A

Complex*16 array, dimension (LDA,N). On entry, the Hermitian matrix A. If UPLO = ‘U’, the leading n by n upper triangular part of A contains the upper triangular part of the matrix A, and the strictly lower triangular part of A is not referenced. If UPLO = ‘L’, the leading n by n lower triangular part of A contains the lower triangular part of the matrix A, and the strictly upper triangular part of A is not referenced. On exit, if INFO = 0, the transformed matrix, stored in the same format as A.

in

lda

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

inout

B

Complex*16 array, dimension (LDB,N). The triangular factor from the Cholesky factorization of B, as returned by ZPOTRF. B is modified by the routine but restored on exit.

in

ldb

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

out

info

= 0: successful exit. < 0: if INFO = -i, the i-th argument had an illegal value.

hegs2#

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