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<div class="moz-cite-prefix">Hi Sakib,<br>
<br>
SCIP only supports linear objective functions. Nonlinear objective
functions f must be modeled through a constraint in combination
with an auxiliary variable based on the equivalence<br>
<br>
min f(x) <=> min t s.t. f(x) <= t<br>
<br>
Happy modeling,<br>
Gregor<br>
<br>
Am 10.04.2017 um 13:53 schrieb sakib mondal:<br>
</div>
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<p><br>
</p>
Thanks Matthias.
<div><br>
</div>
<div>Is there a similar way to add operators on variables in
the objective function.</div>
<div><br>
</div>
<div>For example,
<blockquote type="cite" style="font-family: Calibri, Arial,
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12pt; font-family: Calibri, Arial, Helvetica, sans-serif;">
<div id="divtagdefaultwrapper" dir="ltr" style="font-size:
12pt;"><span style="font-size: 12pt;"> model.<span>setObjective(</span>quicksum(exp(x[i])
for i in I), "minimize")</span></div>
<div id="divtagdefaultwrapper" dir="ltr" style="font-size:
12pt;"><span style="font-size: 12pt;"><br>
</span></div>
<div id="divtagdefaultwrapper" dir="ltr" style="font-size:
12pt;"><span style="font-size: 12pt;"><br>
</span></div>
<div id="divtagdefaultwrapper" dir="ltr" style="font-size:
12pt;"><span style="font-size: 12pt;">Thanks a lot.</span></div>
<div id="divtagdefaultwrapper" dir="ltr" style="font-size:
12pt;"><span style="font-size: 12pt;"><br>
</span></div>
<div id="divtagdefaultwrapper" dir="ltr" style="font-size:
12pt;"><span style="font-size: 12pt;">Regards</span></div>
<div id="divtagdefaultwrapper" dir="ltr" style="font-size:
12pt;"><span style="font-size: 12pt;"> </span><br>
</div>
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<div id="divRplyFwdMsg" dir="ltr"><font
style="font-size:11pt" color="#000000" face="Calibri,
sans-serif"><b>From:</b> Matthias Miltenberger
<a class="moz-txt-link-rfc2396E" href="mailto:miltenberger@zib.de"><miltenberger@zib.de></a><br>
<b>Sent:</b> Friday, April 7, 2017 4:40 PM<br>
<b>To:</b> sakib mondal; <a class="moz-txt-link-abbreviated" href="mailto:scip@zib.de">scip@zib.de</a><br>
<b>Subject:</b> Re: [SCIP] How to add operators on
variables in a constraint</font>
<div> </div>
</div>
<div>Dear Sakib,<br>
<br>
this constraint type is currently not yet supported by
PySCIPOpt. You would need to write a new Conshdlr class
that implements `exp()`. This might be a good starting
point:
<a moz-do-not-send="true" class="moz-txt-link-freetext"
href="https://github.com/SCIP-Interfaces/PySCIPOpt/blob/master/tests/test_tsp.py"
id="LPlnk161841" previewremoved="true">
https://github.com/SCIP-Interfaces/PySCIPOpt/blob/master/tests/test_tsp.py</a>
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<br>
all the best<br>
Matthias<br>
<br>
<div class="moz-cite-prefix">On 07.04.2017 17:15, sakib
mondal wrote:<br>
</div>
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<div id="divtagdefaultwrapper" dir="ltr"
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<p>Hi,</p>
<div style="color:rgb(0,0,0)">
<div>
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<p><br>
</p>
<p>I am trying to use scip solver where one of
the constraints need exponentiation of a
variable. For example,</p>
<p><br>
</p>
<div><br>
</div>
<div><span style="font-size:12pt">
model.addCons(quicksum(exp(x[i]) for i in
I) <span>==1, name="constraint")</span></span><br>
</div>
<div><br>
</div>
<div>Wondering what would be possible ways to
add this.</div>
<div><br>
</div>
<div>I tried searching for such examples, but
could not find any.</div>
<div><br>
</div>
<div>Would appreciate any help. I am using
pyscipopt.</div>
<div><br>
</div>
<div>Regards</div>
<div>Sakib</div>
<div><br>
</div>
<br>
</div>
</div>
</div>
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<pre class="moz-signature" cols="72">--
\__________________
Matthias Miltenberger
Zuse Institute Berlin
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