Visible to Intel only — GUID: GUID-FB95D806-9E4A-45EF-B8C0-BADF8EECF832
Visible to Intel only — GUID: GUID-FB95D806-9E4A-45EF-B8C0-BADF8EECF832
?lasq4
Computes an approximation to the smallest eigenvalue using values of d from the previous transform. Used by ?bdsqr.
Syntax
call slasq4( i0, n0, z, pp, n0in, dmin, dmin1, dmin2, dn, dn1, dn2, tau, ttype, g )
call dlasq4( i0, n0, z, pp, n0in, dmin, dmin1, dmin2, dn, dn1, dn2, tau, ttype, g )
Include Files
- mkl.fi
Description
The routine computes an approximation tau to the smallest eigenvalue using values of d from the previous transform.
Input Parameters
- i0
-
INTEGER. First index.
- n0
-
INTEGER. Last index.
- z
-
REAL for slasq4
DOUBLE PRECISION for dlasq4.
Array, DIMENSION (4n).
z holds the qd array.
- pp
-
INTEGER. pp=0 for ping, pp=1 for pong.
- n0in
-
INTEGER. The value of n0 at start of eigtest.
- dmin
-
REAL for slasq4
DOUBLE PRECISION for dlasq4.
Minimum value of d.
- dmin1
-
REAL for slasq4
DOUBLE PRECISION for dlasq4.
Minimum value of d, excluding d(n0).
- dmin2
-
REAL for slasq4
DOUBLE PRECISION for dlasq4.
Minimum value of d, excluding d(n0) and d(n0-1).
- dn
-
REAL for slasq4
DOUBLE PRECISION for dlasq4. Contains d(n).
- dn1
-
REAL for slasq4
DOUBLE PRECISION for dlasq4. Contains d(n-1).
- dn2
-
REAL for slasq4
DOUBLE PRECISION for dlasq4. Contains d(n-2).
- g
-
REAL for slasq4
DOUBLE PRECISION for dlasq4.
A scalar passed as an argument in order to save its value between calls to ?lasq4.
Output Parameters
- tau
-
REAL for slasq4
DOUBLE PRECISION for dlasq4.
Shift.
- ttype
-
INTEGER. Shift type.
- g
-
REAL for slasq4
DOUBLE PRECISION for dlasq4.
A scalar passed as an argument in order to save its value between calls to ?lasq4.