LAPACK 3.11.0
LAPACK: Linear Algebra PACKage
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subroutine slasq4 | ( | integer | I0, |
integer | N0, | ||
real, dimension( * ) | Z, | ||
integer | PP, | ||
integer | N0IN, | ||
real | DMIN, | ||
real | DMIN1, | ||
real | DMIN2, | ||
real | DN, | ||
real | DN1, | ||
real | DN2, | ||
real | TAU, | ||
integer | TTYPE, | ||
real | G | ||
) |
SLASQ4 computes an approximation to the smallest eigenvalue using values of d from the previous transform. Used by sbdsqr.
Download SLASQ4 + dependencies [TGZ] [ZIP] [TXT]
SLASQ4 computes an approximation TAU to the smallest eigenvalue using values of d from the previous transform.
[in] | I0 | I0 is INTEGER First index. |
[in] | N0 | N0 is INTEGER Last index. |
[in] | Z | Z is REAL array, dimension ( 4*N0 ) Z holds the qd array. |
[in] | PP | PP is INTEGER PP=0 for ping, PP=1 for pong. |
[in] | N0IN | N0IN is INTEGER The value of N0 at start of EIGTEST. |
[in] | DMIN | DMIN is REAL Minimum value of d. |
[in] | DMIN1 | DMIN1 is REAL Minimum value of d, excluding D( N0 ). |
[in] | DMIN2 | DMIN2 is REAL Minimum value of d, excluding D( N0 ) and D( N0-1 ). |
[in] | DN | DN is REAL d(N) |
[in] | DN1 | DN1 is REAL d(N-1) |
[in] | DN2 | DN2 is REAL d(N-2) |
[out] | TAU | TAU is REAL This is the shift. |
[out] | TTYPE | TTYPE is INTEGER Shift type. |
[in,out] | G | G is REAL G is passed as an argument in order to save its value between calls to SLASQ4. |
CNST1 = 9/16