Developer Reference for Intel® oneAPI Math Kernel Library for Fortran
?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
slasq6 dlasq6
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 (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.
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) .