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# slasq4.f - Man Page

SRC/slasq4.f

## Synopsis

### Functions/Subroutines

subroutine slasq4 (i0, n0, z, pp, n0in, dmin, dmin1, dmin2, dn, dn1, dn2, tau, ttype, g)
SLASQ4 computes an approximation to the smallest eigenvalue using values of d from the previous transform. Used by sbdsqr.

## Function/Subroutine Documentation

### 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. Ā

Purpose:

``` SLASQ4 computes an approximation TAU to the smallest eigenvalue
using values of d from the previous transform.```
Parameters

I0

```          I0 is INTEGER
First index.```

N0

```          N0 is INTEGER
Last index.```

Z

```          Z is REAL array, dimension ( 4*N0 )
Z holds the qd array.```

PP

```          PP is INTEGER
PP=0 for ping, PP=1 for pong.```

N0IN

```          N0IN is INTEGER
The value of N0 at start of EIGTEST.```

DMIN

```          DMIN is REAL
Minimum value of d.```

DMIN1

```          DMIN1 is REAL
Minimum value of d, excluding D( N0 ).```

DMIN2

```          DMIN2 is REAL
Minimum value of d, excluding D( N0 ) and D( N0-1 ).```

DN

```          DN is REAL
d(N)```

DN1

```          DN1 is REAL
d(N-1)```

DN2

```          DN2 is REAL
d(N-2)```

TAU

```          TAU is REAL
This is the shift.```

TTYPE

```          TTYPE is INTEGER
Shift type.```

G

```          G is REAL
G is passed as an argument in order to save its value between
calls to SLASQ4.```
Author

Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Further Details:

`  CNST1 = 9/16`

Definition at line 149 of file slasq4.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page slasq4(3) is an alias of slasq4.f(3).

Tue Nov 28 2023 12:08:42 Version 3.12.0 LAPACK