Originally posted by: SystemAdmin

[Jack said:]

Hi,
I am using :

CPLEX Interactive Optimizer 10.1.0
with Simplex, Mixed Integer & Barrier Optimizers
Copyright (c) ILOG 1997-2006

I need to solve the following IP:
*<meta creator=&#039;lp_solve v5.5&#039;>
*<meta rows=3>
*<meta columns=1>
*<meta equalities=1>
*<meta integers=1>
<meta origsense=&#039;MAX&#039;>

NAME          lp_test
ROWS
N  R0
L  R1
G  R2
E  R3
COLUMNS
    MARK0000  'MARKER'                'INTORG'
    C1        R0        -1.000000000  R1        1.0000000000
    C1        R2        2.0000000000  R3        3.0000000000
    MARK0001  'MARKER'                'INTEND'
RHS
    RHS      R1        100.00000000  R2        20.000000000
    RHS      R3        30.000000000
ENDATA

The equalient lp model is:

/* lp_test /

/ Objective function /
max: +C1;

/ Constraints /
R1: +C1 <= 100;<br />R2: +2 C1 >= 20;
R3: +3 C1 = 30;

/ Integer definitions */
int C1;

When I try to solve the mps model, I got :

CPLEX> op
Bound infeasibility column 'C1'.
Presolve time =    0.00 sec.

MIP - Integer infeasible.
Current MIP best bound is infinite.
Solution time =    0.00 sec.  Iterations = 0  Nodes = 0

When I try to solve the lp model, I got :

CPLEX> r
Name of file to read: lp_test_IP_31_model.lp
CPLEX Error  1436: Max or Min missing.
No file read.

But, obviously, the solution should be 10.

Are there some errors in my model ?

Any help is appreciated.

JACK

Jan.  14  2008






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