laesy Interface

public interface laesy

LAESY computes the eigendecomposition of a 2-by-2 symmetric matrix ( ( A, B );( B, C ) ) provided the norm of the matrix of eigenvectors is larger than some threshold value. RT1 is the eigenvalue of larger absolute value, and RT2 of smaller absolute value. If the eigenvectors are computed, then on return ( CS1, SN1 ) is the unit eigenvector for RT1, hence [ CS1 SN1 ] . [ A B ] . [ CS1 -SN1 ] = [ RT1 0 ] [ -SN1 CS1 ] [ B C ] [ SN1 CS1 ] [ 0 RT2 ]


Subroutines

public pure subroutine claesy(a, b, c, rt1, rt2, evscal, cs1, sn1)

Arguments

Type IntentOptional Attributes Name
complex(kind=sp), intent(in) :: a
complex(kind=sp), intent(in) :: b
complex(kind=sp), intent(in) :: c
complex(kind=sp), intent(out) :: rt1
complex(kind=sp), intent(out) :: rt2
complex(kind=sp), intent(out) :: evscal
complex(kind=sp), intent(out) :: cs1
complex(kind=sp), intent(out) :: sn1

public pure subroutine zlaesy(a, b, c, rt1, rt2, evscal, cs1, sn1)

Arguments

Type IntentOptional Attributes Name
complex(kind=dp), intent(in) :: a
complex(kind=dp), intent(in) :: b
complex(kind=dp), intent(in) :: c
complex(kind=dp), intent(out) :: rt1
complex(kind=dp), intent(out) :: rt2
complex(kind=dp), intent(out) :: evscal
complex(kind=dp), intent(out) :: cs1
complex(kind=dp), intent(out) :: sn1

Module Procedures

public interface stdlib_claesy()

Arguments

None

public interface stdlib_zlaesy()

Arguments

None