hbgst Interface

public interface hbgst

HBGST reduces a complex Hermitian-definite banded generalized eigenproblem Ax = lambdaBx to standard form Cy = lambday, such that C has the same bandwidth as A. B must have been previously factorized as SHS by CPBSTF, using a split Cholesky factorization. A is overwritten by C = XHAX, where X = S(-1)*Q and Q is a unitary matrix chosen to preserve the bandwidth of A.


Subroutines

public pure subroutine chbgst(vect, uplo, n, ka, kb, ab, ldab, bb, ldbb, x, ldx, work, rwork, info)

Arguments

Type IntentOptional Attributes Name
character(len=1), intent(in) :: vect
character(len=1), intent(in) :: uplo
integer(kind=ilp), intent(in) :: n
integer(kind=ilp), intent(in) :: ka
integer(kind=ilp), intent(in) :: kb
complex(kind=sp), intent(inout) :: ab(ldab,*)
integer(kind=ilp), intent(in) :: ldab
complex(kind=sp), intent(in) :: bb(ldbb,*)
integer(kind=ilp), intent(in) :: ldbb
complex(kind=sp), intent(out) :: x(ldx,*)
integer(kind=ilp), intent(in) :: ldx
complex(kind=sp), intent(out) :: work(*)
real(kind=sp), intent(out) :: rwork(*)
integer(kind=ilp), intent(out) :: info

public pure subroutine zhbgst(vect, uplo, n, ka, kb, ab, ldab, bb, ldbb, x, ldx, work, rwork, info)

Arguments

Type IntentOptional Attributes Name
character(len=1), intent(in) :: vect
character(len=1), intent(in) :: uplo
integer(kind=ilp), intent(in) :: n
integer(kind=ilp), intent(in) :: ka
integer(kind=ilp), intent(in) :: kb
complex(kind=dp), intent(inout) :: ab(ldab,*)
integer(kind=ilp), intent(in) :: ldab
complex(kind=dp), intent(in) :: bb(ldbb,*)
integer(kind=ilp), intent(in) :: ldbb
complex(kind=dp), intent(out) :: x(ldx,*)
integer(kind=ilp), intent(in) :: ldx
complex(kind=dp), intent(out) :: work(*)
real(kind=dp), intent(out) :: rwork(*)
integer(kind=ilp), intent(out) :: info

Module Procedures

public interface stdlib_chbgst()

Arguments

None

public interface stdlib_zhbgst()

Arguments

None