DIXON3DQ.SIF

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* SET UP THE INITIAL DATA *
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NAME          DIXON3DQ

*   Problem :
*   *********

*   Dixon's tridiagonal quadratic.

*   Source: problem 156 (p. 51) in
*   A.R. Buckley,
*   "Test functions for unconstrained minimization",
*   TR 1989CS-3, Mathematics, statistics and computing centre,
*   Dalhousie University, Halifax (CDN), 1989.

*   SIF input: Ph. Toint, Dec 1989.

*   classification QUR2-AN-V-0

*   Number of variables (variable)

*IE N                   10             $-PARAMETER     original value
*IE N                   100            $-PARAMETER
*IE N                   1000           $-PARAMETER
 IE N                   10000          $-PARAMETER

*   Other parameters

 IE 1                   1
 IE 2                   2
 IA N-1       N         -1

VARIABLES

 DO I         1                        N
 X  X(I)
 ND

GROUPS

 XN G(1)      X(1)      1.0

 DO I         2                        N-1
 IA I+1       I         1
 XN G(I)      X(I)      1.0            X(I+1)    -1.0
 ND

 XN G(N)      X(N)      1.0

CONSTANTS

 X  DIXON3DQ  G(1)      1.0
 X  DIXON3DQ  G(N)      1.0

BOUNDS

 FR DIXON3DQ  'DEFAULT'

START POINT

 XV DIXON3DQ  'DEFAULT' -1.0

GROUP TYPE

 GV L2        GVAR

GROUP USES

 XT 'DEFAULT' L2

OBJECT BOUND

 LO DIXON3DQ            0.0

*   Solution

*LO SOLTN               0.0

ENDATA

*********************
* SET UP THE GROUPS *
* ROUTINE           *
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GROUPS        DIXON3DQ

INDIVIDUALS

 T  L2

 F                      GVAR * GVAR
 G                      GVAR + GVAR
 H                      2.0

ENDATA