dslect.f3
Usage
Functions/Subroutines
logical function dslect (zr, zi)
DSLECT
Function/Subroutine Documentation
logical function dslect (double precision zr, double precision zi)
DSLECT
Purpose:
!> !> DSLECT returns .TRUE. if the eigenvalue ZR+sqrt(-1)*ZI is to be !> selected, and otherwise it returns .FALSE. !> It is used by DCHK41 to test if DGEES successfully sorts eigenvalues, !> and by DCHK43 to test if DGEESX successfully sorts eigenvalues. !> !> The common block /SSLCT/ controls how eigenvalues are selected. !> If SELOPT = 0, then DSLECT return .TRUE. when ZR is less than zero, !> and .FALSE. otherwise. !> If SELOPT is at least 1, DSLECT returns SELVAL(SELOPT) and adds 1 !> to SELOPT, cycling back to 1 at SELMAX. !>
Parameters
ZR
!> ZR is DOUBLE PRECISION !> The real part of a complex eigenvalue ZR + i*ZI. !>
ZI
!> ZI is DOUBLE PRECISION !> The imaginary part of a complex eigenvalue ZR + i*ZI. !>
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Definition at line 61 of file dslect.f.