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<p>Hi Mike and Marc,</p>
<p>if I understand the question correctly, the first option would be
to register a pricer with SCIP for every arc and the second to
have one pricer that processes all arcs at once? I think in the
first case, SCIP will skip the remaining pricers if sufficient new
variables have already been generated in the current pricing
iteration, see settings pricing->maxvars and
pricing->maxvarsroot. As far as I can tell, these settings are
only relevant for the SCIPpriceLoop in solve.c. If your pricing is
cheap and generates many variables, it might be better to price
variables for all arcs at once and let SCIP select the best
maxvars(root) many variables depending on the score you give them.
If you generate less than maxvars(root) many variables, I think
both options will be the same regarding SCIP.</p>
<p>All the best<br>
Alex</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 12.05.25 07:38, Marc Pfetsch wrote:<br>
</div>
<blockquote type="cite"
cite="mid:5a6cf16c-9673-43fa-add2-eba7f30185a1@mathematik.tu-darmstadt.de">
<br>
<br>
Hi Mike,
<br>
<br>
I don't think it matters for SCIP. I guess it will depend on your
implementation what is easier or faster.
<br>
<br>
Best
<br>
<br>
Marc
<br>
<br>
<br>
On 10/05/2025 06:15, Hewitt, Michael wrote:
<br>
<blockquote type="cite">I am using the SCIP framework to implement
a column generation algorithm for a MIP defined on a network in
which I generate variables for each arc in the network by
solving a pricing problem. Does it matter which of the following
I do:
<br>
<br>
1. For each arc, solve the pricing problem and add variables
with
<br>
negative reduced costs via SCIPcreateVar and
SCIPaddPricedVar
<br>
<br>
Or
<br>
<br>
2. Solve the pricing problem for each arc, then after all arcs
have
<br>
been priced add the variables with negative reduced costs
via
<br>
SCIPcreateVar and SCIPaddPricedVar
<br>
<br>
Thanks, Mike
<br>
<br>
Mike Hewitt
<br>
Professor
<br>
Quinlan School of Business, Loyola University Chicago
<br>
<a class="moz-txt-link-abbreviated" href="mailto:mhewitt3@luc.edu">mhewitt3@luc.edu</a> <a class="moz-txt-link-rfc2396E" href="mailto:mhewitt3@luc.edu"><mailto:mhewitt3@luc.edu></a>
<br>
<br>
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<pre class="moz-signature" cols="72">--
Alexander Helber
Research and Teaching Assistant
Chair of Operations Research
RWTH Aachen University
Kackertstrasse 7
52072 Aachen
Germany
Web: or.rwth-aachen.de
Mail: <a class="moz-txt-link-abbreviated" href="mailto:helber@or.rwth-aachen.de">helber@or.rwth-aachen.de</a></pre>
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