Developer Reference for Intel® oneAPI Math Kernel Library for Fortran
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?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 (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.
 - 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).