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
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) .