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Hi Mona,<br>
<br>
Could you include the log of the solver so that I can check if there
is some message indicating what happened ?<br>
<br>
Cheers<br>
<br>
<div class="moz-cite-prefix">On 12-11-2015 12:00, Mona Rahn wrote:<br>
</div>
<blockquote
cite="mid:CAJW3XAJMfFF-+cmcf9oo7dmjhTsMBiL8-E4n5EJosmyB+Du6sA@mail.gmail.com"
type="cite">
<div dir="ltr">Hi Haroldo,
<div><br>
</div>
<div>Thanks for your answer.</div>
<div><br>
</div>
<div>I actually meant getting the mipstart (after solving), not
entering it to the solver. Anyway, I now programmed my own
function to do that, and I feed the solver the mipstart upon
the next solve via setMIPStart as you suggested - but it
doesn't seem to change anything! When I resolve, it still
takes quite a lot of time to find a feasible solution. Do you
have an idea on that?</div>
<div><br>
</div>
<div>Thanks a lot for your help!</div>
<div><br>
</div>
<div>Kind regards,</div>
<div>Mona</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Wed, Nov 11, 2015 at 4:37 PM,
Haroldo Gambini Santos <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:haroldo.santos@gmail.com" target="_blank"><a class="moz-txt-link-abbreviated" href="mailto:haroldo.santos@gmail.com">haroldo.santos@gmail.com</a></a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000"> Hi Mona,<br>
<br>
To enter MIPStart programatically you should call<br>
<br>
CbcModel method<br>
void setMIPStart( const std::vector<
std::pair< std::string, double > > &mips )
{<br>
this->mipStart_ = mips;<br>
}<br>
<br>
MIPstart is used when you an initial feasible solution
to enter to the solver.<br>
<br>
You need to inform shit solution using pairs<br>
<br>
variableName value<br>
<br>
variable names are used because the initial solution may
be used in the pre-processed model (variable indexes
change).<br>
<br>
You only need to enter the main active decision
variables. Auxiliary variables are computed if they
exist.<br>
<br>
Cheers,<br>
<br>
Haroldo
<div>
<div><br>
<br>
<br>
<br>
<div>On 11-11-2015 12:38, Mona Rahn wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">
<div>@ John:</div>
<div>Thanks for your answer.</div>
<div>Is there a function to save the mipstart
(as getMIPStart doesn't seem to do it)? And do
you have an example about mipstart?</div>
<div>The event handler works perfectly btw! :)
Thanks.</div>
<div><br>
</div>
<div>@ Ted, Babak: thank you too!</div>
<div><br>
</div>
<div>Btw, can anybody tell me is the precise
difference is between</div>
<div>- hotstart</div>
<div>- warmstart</div>
<div>- resolve </div>
<div>- mipstart?</div>
<div><br>
</div>
<div>Kind regards,</div>
<div>Mona</div>
<div><br>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Sat, Nov 7, 2015
at 3:46 PM, John Forrest <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:john.forrest@fastercoin.com"
target="_blank"><a class="moz-txt-link-abbreviated" href="mailto:john.forrest@fastercoin.com">john.forrest@fastercoin.com</a></a>></span>
wrote:<br>
<blockquote class="gmail_quote"
style="margin:0px 0px 0px
0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
<div>Mona,<span><br>
<br>
On 06/11/15 13:45, Mona Rahn wrote:<br>
</span></div>
<span>
<blockquote type="cite">
<div dir="ltr">
<div>Hi!<br>
</div>
<div><br>
</div>
<div>I have three questions:</div>
<div><br>
</div>
<div>1) I am pretty new in using
CBC with C++. Do you have a tip
on a good way to start, i.e. a
documentation / tutorial /
handbook for beginners? Most of
the stuff I found online was
aimed at a much higher level of
knowledge. The documentation
link that can be found on the
COIN-OR website (<a
moz-do-not-send="true"
href="https://projects.coin-or.org/Cbc"
target="_blank"><a class="moz-txt-link-freetext" href="https://projects.coin-or.org/Cbc">https://projects.coin-or.org/Cbc</a></a>
at the bottom) doesn't work.</div>
<div><br>
</div>
</div>
</blockquote>
</span> Documentation has never been the
strong point of Cbc. It can be useful
to invoke cbc and try ? and then look at
individual options - see 2)<span><br>
<br>
<blockquote type="cite">
<div dir="ltr">
<div>2) I have an minimization LP
that I resolve several times
with different objectives. That
is, I solve it, upper bound the
unique variable appearing in my
first objective function to the
calculated value, and set
another variable as my
objective.</div>
<div>Now, my question is: The
solver appears to start from
scratch every time I call it,
but I would like to keep the old
solution and start from there.
Is there a way to do this? I
have seen the warm start in
OsiCbcSolverinterface, but I am
not sure how to use it.</div>
<div><br>
</div>
</div>
</blockquote>
<br>
</span> If you do cbc and then
mipstart?? you will see that you can
save the solution from one run and then
use it as an input solution to next.<span><br>
<blockquote type="cite">
<div dir="ltr">
<div>3) I would like to have set a
time limit that only stops the
program if there is already a
solution found (which isn't
necessarily optimal), but not if
it is still searching for a
solution. The only time limit I
have found is
CbcModel::setMaximumSeconds, but
this stops the program no matter
what. Do you have a solution for
this?</div>
<div><br>
</div>
</div>
</blockquote>
<br>
</span> You may wish to use the drivers
that allow you to call cbc as normal but
with changes. Look at driver6.cpp. If
you have a driver like that then you
could check if you have a solution and
then stop on time. I would suggest
modifying MyEventHandler3::event to
check if event was treeStatus and
solution found and too many seconds.<span><font
color="#888888"><br>
<br>
John Forrest<br>
</font></span>
<blockquote type="cite"><span>
<div dir="ltr">
<div>Thanks a lot in advance.</div>
<div><br>
</div>
<div>Kind regards,</div>
<div>Mona</div>
</div>
<br>
<fieldset></fieldset>
<br>
</span><span>
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<span><font color="#888888">
<pre cols="72">--
==================================================
Haroldo Gambini Santos
D.Sc, Computer Science
Universidade Federal de Ouro Preto
<a moz-do-not-send="true" href="http://www.decom.ufop.br/haroldo/" target="_blank">http://www.decom.ufop.br/haroldo/</a></pre>
</font></span></div>
</blockquote>
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</div>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
==================================================
Haroldo Gambini Santos
D.Sc, Computer Science
Universidade Federal de Ouro Preto
<a class="moz-txt-link-freetext" href="http://www.decom.ufop.br/haroldo/">http://www.decom.ufop.br/haroldo/</a></pre>
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