Visible to Intel only — GUID: GUID-12EABB0D-2634-4FE7-BB19-E185CE03375D
Visible to Intel only — GUID: GUID-12EABB0D-2634-4FE7-BB19-E185CE03375D
?lasq6
Computes one dqd transform in ping-pong form. Used by ?bdsqr and ?stegr.
Syntax
call slasq6( i0, n0, z, pp, dmin, dmin1, dmin2, dn, dnm1, dnm2 )
call dlasq6( i0, n0, z, pp, dmin, dmin1, dmin2, dn, dnm1, dnm2 )
Include Files
- mkl.fi
Description
The routine ?lasq6 computes one dqd (shift equal to zero) transform in ping-pong form, with protection against underflow and overflow.
Input Parameters
- i0
-
INTEGER. First index.
- n0
-
INTEGER. Last index.
- z
-
REAL for slasq6
DOUBLE PRECISION for dlasq6.
Array, DIMENSION (4n). Z holds the qd array. emin is stored in z(4*n0) to avoid an extra argument.
- pp
-
INTEGER. pp=0 for ping, pp=1 for pong.
Output Parameters
- dmin
-
REAL for slasq6
DOUBLE PRECISION for dlasq6.
Minimum value of d.
- dmin1
-
REAL for slasq6
DOUBLE PRECISION for dlasq6.
Minimum value of d, excluding d(n0).
- dmin2
-
REAL for slasq6
DOUBLE PRECISION for dlasq6.
Minimum value of d, excluding d(n0) and d(n0-1).
- dn
-
REAL for slasq6
DOUBLE PRECISION for dlasq6. Contains d(n0), the last value of d.
- dnm1
-
REAL for slasq6
DOUBLE PRECISION for dlasq6. Contains d(n0-1).
- dnm2
-
REAL for slasq6
DOUBLE PRECISION for dlasq6. Contains d(n0-2).