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LAPACK
3.10.0
LAPACK: Linear Algebra PACKage
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subroutine slasq5 | ( | integer | I0, |
integer | N0, | ||
real, dimension( * ) | Z, | ||
integer | PP, | ||
real | TAU, | ||
real | SIGMA, | ||
real | DMIN, | ||
real | DMIN1, | ||
real | DMIN2, | ||
real | DN, | ||
real | DNM1, | ||
real | DNM2, | ||
logical | IEEE, | ||
real | EPS | ||
) |
SLASQ5 computes one dqds transform in ping-pong form. Used by sbdsqr and sstegr.
Download SLASQ5 + dependencies [TGZ] [ZIP] [TXT]
SLASQ5 computes one dqds transform in ping-pong form, one version for IEEE machines another for non IEEE machines.
[in] | I0 | I0 is INTEGER First index. |
[in] | N0 | N0 is INTEGER Last index. |
[in] | Z | Z is REAL 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. |
[in] | TAU | TAU is REAL This is the shift. |
[in] | SIGMA | SIGMA is REAL This is the accumulated shift up to this step. |
[out] | DMIN | DMIN is REAL Minimum value of d. |
[out] | DMIN1 | DMIN1 is REAL Minimum value of d, excluding D( N0 ). |
[out] | DMIN2 | DMIN2 is REAL Minimum value of d, excluding D( N0 ) and D( N0-1 ). |
[out] | DN | DN is REAL d(N0), the last value of d. |
[out] | DNM1 | DNM1 is REAL d(N0-1). |
[out] | DNM2 | DNM2 is REAL d(N0-2). |
[in] | IEEE | IEEE is LOGICAL Flag for IEEE or non IEEE arithmetic. |
[in] | EPS | EPS is REAL This is the value of epsilon used. |