DSLECT
Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
February 2007
February 2007
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 succesfully sorts eigenvalues,
and by DCHK43 to test if DGEESX succesfully 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.
selected, and otherwise it returns .FALSE.
It is used by DCHK41 to test if DGEES succesfully sorts eigenvalues,
and by DCHK43 to test if DGEESX succesfully 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.
Arguments
| ZR |
(input) DOUBLE PRECISION
The real part of a complex eigenvalue ZR + i*ZI.
|
| ZI |
(input) DOUBLE PRECISION
The imaginary part of a complex eigenvalue ZR + i*ZI.
|