LP-solution, simple formulation
-------------------------------

CPLEX> read opgave15.lp
Problem 'opgave15.lp' read.
Read time =    0.02 sec.
CPLEX> opt
Tried aggregator 1 time.
No LP presolve or aggregator reductions.
Presolve time =    0.00 sec.

Iteration log . . .
Iteration:     1    Objective     =             1.000000

Primal - Optimal:  Objective =    3.5000000000e+00
Solution time =    0.00 sec.  Iterations = 9 (0)

CPLEX> dis sol var -
Variable Name           Solution Value
x1                            0.500000
x2                            0.500000
x3                            0.500000
x4                            0.500000
x5                            0.500000
x6                            0.500000
x7                            0.500000


IP-solution, simple formulation
-------------------------------

CPLEX> opt
Tried aggregator 1 time.
No MIP presolve or aggregator reductions.
Presolve time =    0.00 sec.
Maximum infeasibility variable selection.
Objective is integral.

        Nodes                                         Cuts/
   Node  Left     Objective  IInf  Best Integer     Best Node    ItCnt

      0     0        3.5000     7                      3.5000        9
*     1     1        2.0000     0        2.0000        3.5000       13

Integer optimal solution:  Objective =    2.0000000000e+00
Solution time =    0.01 sec.  Iterations = 17  Nodes = 3


LP-solution, with added cut
---------------------------

CPLEX> read node.lp
Problem 'node.lp' read.
Read time =    0.03 sec.
CPLEX> opt
Tried aggregator 1 time.
No LP presolve or aggregator reductions.
Presolve time =    0.00 sec.

Iteration log . . .
Iteration:     1    Objective     =             1.000000

Primal - Optimal:  Objective =    2.0000000000e+00
Solution time =    0.00 sec.  Iterations = 3 (0)

CPLEX> dis sol var -
Variable Name           Solution Value
x1                            1.000000
x2                            1.000000
All other variables in the range 1-7 are zero.