Visible to Intel only — GUID: GUID-4AA1632F-47FA-4DCE-8B09-6F06745A39D1
Visible to Intel only — GUID: GUID-4AA1632F-47FA-4DCE-8B09-6F06745A39D1
?lasq3
Checks for deflation, computes a shift and calls dqds. Used by ?bdsqr.
Syntax
call slasq3( i0, n0, z, pp, dmin, sigma, desig, qmax, nfail, iter, ndiv, ieee, ttype, dmin1, dmin2, dn, dn1, dn2, g, tau )
call dlasq3( i0, n0, z, pp, dmin, sigma, desig, qmax, nfail, iter, ndiv, ieee, ttype, dmin1, dmin2, dn, dn1, dn2, g, tau )
Include Files
- mkl.fi
Description
The routine ?lasq3 checks for deflation, computes a shift tau, and calls dqds. In case of failure, it changes shifts, and tries again until output is positive.
Input Parameters
- i0
-
INTEGER. First index.
- n0
-
INTEGER. Last index.
- z
-
REAL for slasq3
DOUBLE PRECISION for dlasq3.
Array, DIMENSION (4n). z holds the qd array.
- pp
-
INTEGER. pp=0 for ping, pp=1 for pong. pp=2 indicates that flipping was applied to the Z array and that the initial tests for deflation should not be performed.
- desig
-
REAL for slasq3
DOUBLE PRECISION for dlasq3.
Lower order part of sigma.
- qmax
-
REAL for slasq3
DOUBLE PRECISION for dlasq3.
Maximum value of q.
- ieee
-
LOGICAL.
Flag for ieee or non-ieee arithmetic (passed to ?lasq5).
- ttype
-
INTEGER.
Shift type.
- dmin1, dmin2, dn, dn1, dn2, g, tau
-
REAL for slasq3
DOUBLE PRECISION for dlasq3.
These scalars are passed as arguments in order to save their values between calls to ?lasq3.
Output Parameters
- dmin
-
REAL for slasq3
DOUBLE PRECISION for dlasq3.
Minimum value of d.
- pp
-
INTEGER. pp=0 for ping, pp=1 for pong. pp=2 indicates that flipping was applied to the Z array and that the initial tests for deflation should not be performed.
- sigma
-
REAL for slasq3
DOUBLE PRECISION for dlasq3.
Sum of shifts used in the current segment.
- desig
-
Lower order part of sigma.
- nfail
-
INTEGER. Number of times shift was too big.
- iter
-
INTEGER. Number of iterations.
- ndiv
-
INTEGER. Number of divisions.
- ttype
-
INTEGER.
Shift type.
- dmin1, dmin2, dn, dn1, dn2, g, tau
-
REAL for slasq3
DOUBLE PRECISION for dlasq3.
These scalars are passed as arguments in order to save their values between calls to ?lasq3.