dlasq5.f (3) - Linux Manuals
NAME
dlasq5.f -
SYNOPSIS
Functions/Subroutines
subroutine dlasq5 (I0, N0, Z, PP, TAU, SIGMA, DMIN, DMIN1, DMIN2, DN, DNM1, DNM2, IEEE, EPS)
DLASQ5 computes one dqds transform in ping-pong form. Used by sbdsqr and sstegr.
Function/Subroutine Documentation
subroutine dlasq5 (integerI0, integerN0, double precision, dimension( * )Z, integerPP, double precisionTAU, double precisionSIGMA, double precisionDMIN, double precisionDMIN1, double precisionDMIN2, double precisionDN, double precisionDNM1, double precisionDNM2, logicalIEEE, double precisionEPS)
DLASQ5 computes one dqds transform in ping-pong form. Used by sbdsqr and sstegr.
Purpose:
-
DLASQ5 computes one dqds transform in ping-pong form, one version for IEEE machines another for non IEEE machines.
Parameters:
-
I0
I0 is INTEGER First index.
N0N0 is INTEGER Last index.
ZZ is DOUBLE PRECISION array, dimension ( 4*N ) Z holds the qd array. EMIN is stored in Z(4*N0) to avoid an extra argument.
PPPP is INTEGER PP=0 for ping, PP=1 for pong.
TAUTAU is DOUBLE PRECISION This is the shift.
SIGMASIGMA is DOUBLE PRECISION This is the accumulated shift up to this step.
DMINDMIN is DOUBLE PRECISION Minimum value of d.
DMIN1DMIN1 is DOUBLE PRECISION Minimum value of d, excluding D( N0 ).
DMIN2DMIN2 is DOUBLE PRECISION Minimum value of d, excluding D( N0 ) and D( N0-1 ).
DNDN is DOUBLE PRECISION d(N0), the last value of d.
DNM1DNM1 is DOUBLE PRECISION d(N0-1).
DNM2DNM2 is DOUBLE PRECISION d(N0-2).
IEEEIEEE is LOGICAL Flag for IEEE or non IEEE arithmetic.
EPSEPS is DOUBLE PRECISION This is the value of epsilon used.
Author:
-
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
- September 2012
Definition at line 144 of file dlasq5.f.
Author
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