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<div class="moz-cite-prefix">Dear Abdelkader Ouali,<br>
<br>
I am afraid there is no ad-hoc method available for this in SCIP.
The methods available through the <a
href="http://scip.zib.de/doc/html_devel/cons__linear_8h.php">linear
constraint<br>
handler</a> might be sufficient here:<br>
<br>
1. Create a secondary SCIP-instance dualscip and a problem inside
dualscip.<br>
2. Create variables for every linear constraint in dualscip<br>
3. Create a new linear constraint in dualscip for every variable<br>
4. Iterate over the constraints once in order to have their
variables, vals (=coefficients), and number, and add<br>
the coefficients for the corresponding dual variable of this
constraint to every dual constraint it should appear in.<br>
5. Now you can use the LP-writer for the dualscip-Problem.<br>
<br>
This is quite a nice SCIP-exercise, isn't it? :)<br>
<br>
The reason why SCIP does not come with such a functionality (yet)
is its constraint-based nature. It does not<br>
always make sense to speak of the dual of a SCIP problem. The dual
of the LP that SCIP builds internally might<br>
be different from what you exspect, because the problem has
already undergone a transformation through<br>
various presolving steps.<br>
<br>
Kind regards<br>
Gregor<br>
<br>
<br>
Am 09.07.2014 10:01, schrieb Abdelkader Ouali:<br>
</div>
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<div dir="ltr">Hello,
<div><br>
</div>
<div>How to write dual problem of the original problem in lp
format file </div>
<div>using SCIP routines</div>
<div><br>
</div>
<div>Thanks </div>
<div><br>
</div>
<div>---</div>
<div>Abdelkader Ouali</div>
<div><br>
</div>
</div>
<br>
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