[Symphony] Incorrect solution for a simple linear programming model

[Federico Larumbe]

Hi,

I am testing Symphony with a simple example in AMPL format:

symphony -F file.mod -D file.dat

-- file.mod ------------------
var y >= 0;

minimize ObjectiveFunction: y;

subject to C1:   y >= 1.0;
subject to C2:   y <= 2.0;
subject to C3:   y  = 1.1;

end;
------------------------------

-- file.dat ------------------
data;
end;
------------------------------


The solution given by the program is 2.0 instead of 1.1 (see attached
file). If I choose maximize, the solution is 1.0. If I remove C3, the
problem is unbounded. Is there any option that I missing?

I compiled Sympthony in SUSE Linux with gcc 4.5.1 with the following
commands:

./configure --with-gmpl --enable-openm
make


Thanks a lot,
Federico.

-- 
Federico Larumbe
École Polytechnique de Montréal
Montréal H3C 3A9

Group for Research in Decision Analysis (GERAD)
tel   +1 514 3406053 xt 6931
fax   +1 514 3405665
http://www.gerad.ca/en/directory/details.php?id=1214
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://list.coin-or.org/pipermail/symphony/attachments/20120719/c4efea40/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: file.output
Type: application/octet-stream
Size: 4483 bytes
Desc: not available
URL: <http://list.coin-or.org/pipermail/symphony/attachments/20120719/c4efea40/attachment.obj>