Function **SELECT** is:

The call:LOGICAL FUNCTION SELECT(X,Y)

USE LA_PRECISION, ONLY: WPwp

INTRINSIC EPSILON

REAL(WP), INTENT(IN) :: X,Y

! Select the real eigenvalues

! within the working precision

IF (ABS(Y) EPSILON(1.0_WP)) THEN

SELECT = .TRUE.

ELSE

SELECT = .FALSE.

END IF

END FUNCTION SELECT

, , , , , and
on exit:

The real-Schur form , the matrix of Schur vectors , and the eigenvalues of matrix are:

and