<div dir="ltr"><div class="gmail_default" style="font-family:monospace,monospace;font-size:small"><br></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Nov 13, 2017 at 10:41 AM, Bjørn Sigurd Johansen (Spider Solutions AS) <span dir="ltr"><<a href="mailto:bjorn.sigurd.johansen@spidersolutions.no" target="_blank">bjorn.sigurd.johansen@spidersolutions.no</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p class="MsoNormal"><span lang="EN-US">Thx : )<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">Three modelling questions:<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><b><span lang="EN-US"><u></u> <u></u></span></b></p>
<p class="MsoNormal"><b><span lang="EN-US">Question 1:</span></b><span lang="EN-US"> Is there any advantage in defining bounds in BOUNDS section rather than in SUBJECT TO section? I.e.
is one of the following preferred for an (integer and/or continuous) variable?<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">SUBJECT TO<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">I1>=0<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">I1<=10<u></u><u></u></span></p>
<div style="border:none;border-bottom:solid windowtext 1.0pt;padding:0cm 0cm 1.0pt 0cm">
<p class="MsoNormal" style="border:none;padding:0cm"><span lang="EN-US">------------------------- alternatively -------------------------
<u></u><u></u></span></p>
<p class="MsoNormal" style="border:none;padding:0cm"><span lang="EN-US">BOUNDS<u></u><u></u></span></p>
<p class="MsoNormal" style="border:none;padding:0cm"><span lang="EN-US">0 <= I1 <= 10<u></u><u></u></span></p>
<p class="MsoNormal" style="border:none;padding:0cm"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal" style="border:none;padding:0cm"><br></p></div></div></div></blockquote><div><div class="gmail_default" style="font-family:monospace,monospace;font-size:small;display:inline">I think that to define in bounds is better.</div></div><div><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div lang="NO-BOK" link="blue" vlink="purple"><div class="m_-4019400050550869115WordSection1"><div style="border:none;border-bottom:solid windowtext 1.0pt;padding:0cm 0cm 1.0pt 0cm"><p class="MsoNormal" style="border:none;padding:0cm"></p>
<p class="MsoNormal" style="border:none;padding:0cm"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal" style="border:none;padding:0cm"><b><span lang="EN-US">Question 2:</span></b><span lang="EN-US"> What is/is there any purpose of defining no bounds, i.e. using FREE in
BOUNDS section, for integer variables?<u></u><u></u></span></p>
<p class="MsoNormal" style="border:none;padding:0cm"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal" style="border:none;padding:0cm"><span lang="EN-US">BOUNDS<u></u><u></u></span></p>
<p class="MsoNormal" style="border:none;padding:0cm"><span lang="EN-US">I1 FREE</span></p></div></div></div></blockquote><div><div class="gmail_default" style="font-family:monospace,monospace;font-size:small;display:inline">Free variables can assume positive and negative values.</div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div lang="NO-BOK" link="blue" vlink="purple"><div class="m_-4019400050550869115WordSection1"><div style="border:none;border-bottom:solid windowtext 1.0pt;padding:0cm 0cm 1.0pt 0cm"><p class="MsoNormal" style="border:none;padding:0cm"><span lang="EN-US"><u></u><u></u></span></p>
<p class="MsoNormal" style="border:none;padding:0cm"><span lang="EN-US">GENERAL
<u></u><u></u></span></p>
<p class="MsoNormal" style="border:none;padding:0cm"><span lang="EN-US">I1<u></u><u></u></span></p>
<p class="MsoNormal" style="border:none;padding:0cm"><span lang="EN-US">------------------------- alternatively only -------------------------
<u></u><u></u></span></p>
<p class="MsoNormal" style="border:none;padding:0cm"><span lang="EN-US">GENERAL
<u></u><u></u></span></p>
<p class="MsoNormal" style="border:none;padding:0cm"><span lang="EN-US">I1<u></u><u></u></span></p>
<p class="MsoNormal" style="border:none;padding:0cm"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal" style="border:none;padding:0cm"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal" style="border:none;padding:0cm"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal" style="border:none;padding:0cm"><b><span lang="EN-US">Question 3:</span></b><span lang="EN-US"> Is there any difference between the following two?<u></u><u></u></span></p>
<p class="MsoNormal" style="border:none;padding:0cm"><span lang="EN-US">V1>=0<u></u><u></u></span></p>
<p class="MsoNormal" style="border:none;padding:0cm"><span lang="EN-US">V1>=+0<u></u><u></u></span></p>
<p class="MsoNormal" style="border:none;padding:0cm"><span lang="EN-US">(I have seen “+0” being used several places).</span></p></div></div></div></blockquote><div><br></div><div class="gmail_default" style=""><font face="monospace, monospace">When saving LPs you'll probably see -0 +0 these are all zero. When saving the solution you'll probably see very small values (such 1e-12)</font> which are zero too but appear as small values due to the limited precision arithmetic.</div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div lang="NO-BOK" link="blue" vlink="purple"><div class="m_-4019400050550869115WordSection1"><div style="border:none;border-bottom:solid windowtext 1.0pt;padding:0cm 0cm 1.0pt 0cm">
<p class="MsoNormal" style="border:none;padding:0cm"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal" style="border:none;padding:0cm"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal" style="border:none;padding:0cm"><span lang="EN-US">Thanks in advance,<u></u><u></u></span></p>
<p class="MsoNormal" style="border:none;padding:0cm"><span lang="EN-US">Bjorn<u></u><u></u></span></p>
<p class="MsoNormal" style="border:none;padding:0cm"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal" style="border:none;padding:0cm"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal" style="border:none;padding:0cm"><span lang="EN-US"><u></u> <u></u></span></p>
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<p class="MsoNormal"><b><span lang="EN-US">From:</span></b><span lang="EN-US"> Haroldo Santos [mailto:<a href="mailto:haroldo.santos@gmail.com" target="_blank">haroldo.santos@gmail.<wbr>com</a>]
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<b>Sent:</b> mandag 13. november 2017 13:03<br>
<b>To:</b> Bjørn Sigurd Johansen (Spider Solutions AS) <<a href="mailto:bjorn.sigurd.johansen@spidersolutions.no" target="_blank">bjorn.sigurd.johansen@<wbr>spidersolutions.no</a>><br>
<b>Cc:</b> <a href="mailto:cbc@list.coin-or.org" target="_blank">cbc@list.coin-or.org</a>; <a href="mailto:cbc@coin-or.org" target="_blank">cbc@coin-or.org</a><br>
<b>Subject:</b> Re: [Cbc] lp file format<u></u><u></u></span></p><div><div class="h5">
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Courier New"">Hi,<u></u><u></u></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Courier New""><u></u> <u></u></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Courier New"">I think that there is no cbc specific (more precisely Osi) LP format documentation. The LP file format was introduced in CPLEX and I think that CPLEX has the official documentation.<u></u><u></u></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Courier New""><u></u> <u></u></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Courier New""><u></u> <u></u></span></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">On Mon, Nov 13, 2017 at 5:54 AM, Bjørn Sigurd Johansen (Spider Solutions AS) <<a href="mailto:bjorn.sigurd.johansen@spidersolutions.no" target="_blank">bjorn.sigurd.johansen@<wbr>spidersolutions.no</a>> wrote:<u></u><u></u></p>
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<p class="MsoNormal"><span lang="EN-US">Hi!</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">Is there any description on the CBC lp file format available ?</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">Or may the Cplex format description at
<a href="http://lpsolve.sourceforge.net/5.0/CPLEX-format.htm" target="_blank">http://lpsolve.sourceforge.<wbr>net/5.0/CPLEX-format.htm</a> be used ?</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">Best,</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">Bjorn</span><u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">-- <u></u><u></u></p>
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<p class="MsoNormal"><span style="font-family:"Courier New"">==============================<wbr>==============================<wbr>=<br>
Haroldo Gambini Santos<br>
Computing Department<br>
Universidade Federal de Ouro Preto - UFOP<br>
email: haroldo [at ] <a href="http://iceb.ufop.br" target="_blank">iceb.ufop.br</a><br>
home/research page: <a href="http://www.decom.ufop.br/haroldo/" target="_blank">www.decom.ufop.br/haroldo</a><br>
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<br>
It has long been an axiom of mine that the little things are infinitely<br>
the most important.<br>
-- Sir Arthur Conan Doyle, "A Case of Identity"</span><u></u><u></u></p>
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</blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><span style="font-family:monospace,monospace">=============================================================<br>Haroldo Gambini Santos<br>Computing Department<br>Universidade Federal de Ouro Preto - UFOP<br>email: haroldo [at ] <a href="http://iceb.ufop.br" target="_blank">iceb.ufop.br</a><br>home/research page: <a href="http://www.decom.ufop.br/haroldo/" target="_blank">www.decom.ufop.br/haroldo</a><br><br><br>It has long been an axiom of mine that the little things are infinitely<br>the most important.<br> -- Sir Arthur Conan Doyle, "A Case of Identity"<br></span></div></div></div>
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