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