Developer Reference for Intel® oneAPI Math Kernel Library for Fortran
?lasq5
Computes one dqds transform in ping-pong form. Used by ?bdsqr and ?stegr .
Syntax
call slasq5(i0, n0, z, pp, tau, sigma, dmin, dmin1, dmin2, dn, dnm1, dnm2, ieee, eps)
call dlasq5(i0, n0, z, pp, tau, sigma, dmin, dmin1, dmin2, dn, dnm1, dnm2, ieee, eps)
Include Files
mkl.fi
Description
The routine computes one dqds transform in ping-pong form: one version for ieee machines, another for non-ieee machines.
Input Parameters
- i0
-
INTEGER. First index.
- n0
-
INTEGER . Last index.
- z
-
REAL for slasq5 DOUBLE PRECISION for dlasq5 . Array, DIMENSION (4 n ). 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.
- tau
-
REAL for slasq5 DOUBLE PRECISION for dlasq5 . This is the shift.
- sigma
-
REAL for slasq5 DOUBLE PRECISION for dlasq5 . This is the accumulated shift up to the current point.
- ieee
-
LOGICAL . Flag for IEEE or non-IEEE arithmetic.
- eps
-
REAL for slasq5 DOUBLE PRECISION for dlasq5 . This is the value of epsilon used.
Output Parameters
- dmin
-
REAL for slasq5 DOUBLE PRECISION for dlasq5 . Minimum value of d .
- dmin1
-
REAL for slasq5 DOUBLE PRECISION for dlasq5 . Minimum value of d , excluding d ( n0 ).
- dmin2
-
REAL for slasq5 DOUBLE PRECISION for dlasq5 . Minimum value of d , excluding d ( n0 ) and d(n0-1) .
- dn
-
REAL for slasq5 DOUBLE PRECISION for dlasq5 . Contains d(n0) , the last value of d .
- dnm1
-
REAL for slasq5 DOUBLE PRECISION for dlasq5 . Contains d(n0-1) .
- dnm2
-
REAL for slasq5 DOUBLE PRECISION for dlasq5 . Contains d(n0-2) .