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  3. lapack
  4. slasq6(3)

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slasq6.f(3) LAPACK slasq6.f(3)

NAME

slasq6.f

SYNOPSIS

Functions/Subroutines


subroutine slasq6 (I0, N0, Z, PP, DMIN, DMIN1, DMIN2, DN, DNM1, DNM2)
SLASQ6 computes one dqd transform in ping-pong form. Used by sbdsqr and sstegr.

Function/Subroutine Documentation

subroutine slasq6 (integer I0, integer N0, real, dimension( * ) Z, integer PP, real DMIN, real DMIN1, real DMIN2, real DN, real DNM1, real DNM2)

SLASQ6 computes one dqd transform in ping-pong form. Used by sbdsqr and sstegr.

Purpose: 



 SLASQ6 computes one dqd (shift equal to zero) transform in


 ping-pong form, with protection against underflow and overflow.

Parameters:

I0 



          I0 is INTEGER


        First index.

N0



          N0 is INTEGER


        Last index.

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.

PP



          PP is INTEGER


        PP=0 for ping, PP=1 for pong.

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(N0), the last value of d.

DNM1



          DNM1 is REAL


        d(N0-1).

DNM2



          DNM2 is REAL


        d(N0-2).

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

December 2016

Definition at line 121 of file slasq6.f.

Author

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