![]() |
LAPACK 3.12.0
LAPACK: Linear Algebra PACKage
|
subroutine dlasq6 | ( | integer | i0, |
integer | n0, | ||
double precision, dimension( * ) | z, | ||
integer | pp, | ||
double precision | dmin, | ||
double precision | dmin1, | ||
double precision | dmin2, | ||
double precision | dn, | ||
double precision | dnm1, | ||
double precision | dnm2 | ||
) |
DLASQ6 computes one dqd transform in ping-pong form. Used by sbdsqr and sstegr.
Download DLASQ6 + dependencies [TGZ] [ZIP] [TXT]
DLASQ6 computes one dqd (shift equal to zero) transform in ping-pong form, with protection against underflow and overflow.
[in] | I0 | I0 is INTEGER First index. |
[in] | N0 | N0 is INTEGER Last index. |
[in] | Z | Z is DOUBLE PRECISION array, dimension ( 4*N ) Z holds the qd array. EMIN is stored in Z(4*N0) to avoid an extra argument. |
[in] | PP | PP is INTEGER PP=0 for ping, PP=1 for pong. |
[out] | DMIN | DMIN is DOUBLE PRECISION Minimum value of d. |
[out] | DMIN1 | DMIN1 is DOUBLE PRECISION Minimum value of d, excluding D( N0 ). |
[out] | DMIN2 | DMIN2 is DOUBLE PRECISION Minimum value of d, excluding D( N0 ) and D( N0-1 ). |
[out] | DN | DN is DOUBLE PRECISION d(N0), the last value of d. |
[out] | DNM1 | DNM1 is DOUBLE PRECISION d(N0-1). |
[out] | DNM2 | DNM2 is DOUBLE PRECISION d(N0-2). |