hegvd Interface

public interface hegvd

HEGVD computes all the eigenvalues, and optionally, the eigenvectors of a complex generalized Hermitian-definite eigenproblem, of the form Ax=(lambda)Bx, ABx=(lambda)x, or BAx=(lambda)x. Here A and B are assumed to be Hermitian and B is also positive definite. If eigenvectors are desired, it uses a divide and conquer algorithm. The divide and conquer algorithm makes very mild assumptions about floating point arithmetic. It will work on machines with a guard digit in add/subtract, or on those binary machines without guard digits which subtract like the Cray X-MP, Cray Y-MP, Cray C-90, or Cray-2. It could conceivably fail on hexadecimal or decimal machines without guard digits, but we know of none.


Subroutines

public subroutine chegvd(itype, jobz, uplo, n, a, lda, b, ldb, w, work, lwork, rwork, lrwork, iwork, liwork, info)

Arguments

Type IntentOptional Attributes Name
integer(kind=ilp), intent(in) :: itype
character(len=1), intent(in) :: jobz
character(len=1), intent(in) :: uplo
integer(kind=ilp), intent(in) :: n
complex(kind=sp), intent(inout) :: a(lda,*)
integer(kind=ilp), intent(in) :: lda
complex(kind=sp), intent(inout) :: b(ldb,*)
integer(kind=ilp), intent(in) :: ldb
real(kind=sp), intent(out) :: w(*)
complex(kind=sp), intent(out) :: work(*)
integer(kind=ilp), intent(in) :: lwork
real(kind=sp), intent(out) :: rwork(*)
integer(kind=ilp), intent(in) :: lrwork
integer(kind=ilp), intent(out) :: iwork(*)
integer(kind=ilp), intent(in) :: liwork
integer(kind=ilp), intent(out) :: info

public subroutine zhegvd(itype, jobz, uplo, n, a, lda, b, ldb, w, work, lwork, rwork, lrwork, iwork, liwork, info)

Arguments

Type IntentOptional Attributes Name
integer(kind=ilp), intent(in) :: itype
character(len=1), intent(in) :: jobz
character(len=1), intent(in) :: uplo
integer(kind=ilp), intent(in) :: n
complex(kind=dp), intent(inout) :: a(lda,*)
integer(kind=ilp), intent(in) :: lda
complex(kind=dp), intent(inout) :: b(ldb,*)
integer(kind=ilp), intent(in) :: ldb
real(kind=dp), intent(out) :: w(*)
complex(kind=dp), intent(out) :: work(*)
integer(kind=ilp), intent(in) :: lwork
real(kind=dp), intent(out) :: rwork(*)
integer(kind=ilp), intent(in) :: lrwork
integer(kind=ilp), intent(out) :: iwork(*)
integer(kind=ilp), intent(in) :: liwork
integer(kind=ilp), intent(out) :: info

Module Procedures

public interface stdlib_chegvd()

Arguments

None

public interface stdlib_zhegvd()

Arguments

None