<div dir="ltr"><div class="gmail_default" style="font-family:monospace,monospace;font-size:small">Hi,</div><div class="gmail_default" style="font-family:monospace,monospace;font-size:small"><br></div><div class="gmail_default" style="font-family:monospace,monospace;font-size:small">Tested in trunk now, still gives 825 as optimal,  without cuts gives  70. Could not get zero as optimal yet.</div><div class="gmail_default" style="font-family:monospace,monospace;font-size:small"><br></div><div class="gmail_default" style="font-family:monospace,monospace;font-size:small"><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Dec 29, 2017 at 8:39 AM, John Forrest <span dir="ltr"><<a href="mailto:john.forrest@fastercoin.com" target="_blank">john.forrest@fastercoin.com</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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    <div class="m_-6958349909719266728moz-cite-prefix">Fixed hopefully - stable and trunk.<br>
      <br>
      The original model is not well scaled - one element was 2.1e14 and
      even after preprocessing the problem had to be solved applying
      scaling factors.  The small fast branch and bound is deliberately
      a bit forgiving on this.  When the code thinks it has got a
      solution it double checks.  In this case it did that and threw
      that solution out - but it had left some variables fixed when they
      should not have been.<br>
      <br>
      John Forrest<div><div class="h5"><br>
      <br>
      On 28/12/17 18:30, John Forrest wrote:<br>
    </div></div></div>
    <blockquote type="cite"><div><div class="h5">
      <div class="m_-6958349909719266728moz-cite-prefix">Ryan,<br>
        <br>
        Bug in Cbc.  My first try gave correct result, but I managed to
        get error.  For small problems, Cbc will do a simpler faster
        branch and bound on a portion of the tree.  This is returning
        infeasible - I will look into it.<br>
        <br>
        If you add -depth -100 (which means only go into this simpler
        version at depth 100) then all looked fine.<br>
        <br>
        John Forrest<br>
        On 27/12/17 18:37, Rhavar wrote:<br>
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        <div>I have a problem:<br>
        </div>
        <div><a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__gist.github.com_RHavar_dfb9de631363ecb9e1c326fff5ebd09b&d=DwMDaQ&c=Ngd-ta5yRYsqeUsEDgxhcqsYYY1Xs5ogLxWPA_2Wlc4&r=js2M0T-3OIMIVDvokcKjokJbk0F8QOCd0mT4FsVFE88&m=S4VZrfTJ9vrNsPyEyqDoTZUqb0eG9rdZ8l7-jr8EA9Y&s=dWErV9QjwaNhpQZZkV1ZmdJ_Ofpqgb80lh0-5ORAiSU&e=" target="_blank">https://gist.github.com/<wbr>RHavar/<wbr>dfb9de631363ecb9e1c326fff5ebd0<wbr>9b</a><br>
        </div>
        <div><br>
        </div>
        <div>(lp file and solution file attached)<br>
        </div>
        <div><br>
        </div>
        <div>In the solution it says: "Optimal - objective value"  but I
          think I have found a superior solution by hand:<br>
        </div>
        <div><br>
        </div>
        <div><span class="m_-6958349909719266728s1"><span class="m_-6958349909719266728Apple-converted-space"> </span>o6
            = 1</span><br>
        </div>
        <div>i22 = 1<br>
        </div>
        <div><br>
        </div>
        <div>Which gives a better objective (<span class="m_-6958349909719266728s1">70 instead
            of </span>825)<br>
        </div>
        <div><br>
        </div>
        <div>--<br>
        </div>
        <div><br>
        </div>
        <div>So I guess my question is, does "Optimal - objective
          value"  mean that it's guaranteed to be the optimal solution?
          Or am I doing something wrong? Or is there a bug in cbc? <br>
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        <div><br>
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        <div><br>
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        <div class="m_-6958349909719266728protonmail_signature_block">
          <div class="m_-6958349909719266728protonmail_signature_block-user">
            <div>-Ryan<br>
            </div>
          </div>
          <div class="m_-6958349909719266728protonmail_signature_block-proton m_-6958349909719266728protonmail_signature_block-empty"><br>
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        <br>
        <pre>______________________________<wbr>_________________
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      <p><br>
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      <br>
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      <br>
      </div></div><pre><div><div class="h5">______________________________<wbr>_________________
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</div></div><a class="m_-6958349909719266728moz-txt-link-freetext" href="https://urldefense.proofpoint.com/v2/url?u=https-3A__list.coin-2Dor.org_mailman_listinfo_cbc&d=DwICAg&c=Ngd-ta5yRYsqeUsEDgxhcqsYYY1Xs5ogLxWPA_2Wlc4&r=js2M0T-3OIMIVDvokcKjokJbk0F8QOCd0mT4FsVFE88&m=S4VZrfTJ9vrNsPyEyqDoTZUqb0eG9rdZ8l7-jr8EA9Y&s=SVcz-BvCf0RgvZrRQQxyV89AGoSkVGhfQhv4tx1JKV4&e=" target="_blank">https://urldefense.proofpoint.<wbr>com/v2/url?u=https-3A__list.<wbr>coin-2Dor.org_mailman_<wbr>listinfo_cbc&d=DwICAg&c=Ngd-<wbr>ta5yRYsqeUsEDgxhcqsYYY1Xs5ogLx<wbr>WPA_2Wlc4&r=js2M0T-<wbr>3OIMIVDvokcKjokJbk0F8QOCd0mT4F<wbr>sVFE88&m=<wbr>S4VZrfTJ9vrNsPyEyqDoTZUqb0eG9r<wbr>dZ8l7-jr8EA9Y&s=SVcz-<wbr>BvCf0RgvZrRQQxyV89AGoSkVGhfQhv<wbr>4tx1JKV4&e=</a> 
</pre>
    </blockquote>
    <p><br>
    </p>
  </div>

<br>______________________________<wbr>_________________<br>
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<br></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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