| 1 | <html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Message Handling</title><meta name="generator" content="DocBook XSL Stylesheets V1.66.1"><link rel="start" href="index.html" title="CLP User Guide"><link rel="up" href="ch03.html" title="Chapter 3. |
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| 2 | Not-Quite-So-Basic Model Classes |
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| 3 | "><link rel="prev" href="ch03s02.html" title="Matrix Classes"><link rel="next" href="ch04.html" title="Chapter 4. |
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| 5 | "></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Message Handling</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ch03s02.html">Prev</a> </td><th width="60%" align="center">Chapter 3. |
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| 6 | Not-Quite-So-Basic Model Classes |
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| 7 | </th><td width="20%" align="right"> <a accesskey="n" href="ch04.html">Next</a></td></tr></table><hr></div><div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="messagehandling"></a>Message Handling</h2></div></div></div><p> |
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| 8 | Strictly speaking, message handling is a general COIN topic, but it won't hurt |
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| 9 | to repeat a few important things here. |
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| 10 | </p><p> |
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| 11 | A simple user you may wish to turn off some output. This is done with |
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| 12 | <tt class="function">model.setLogLevel(int value)</tt> |
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| 13 | where 0 gives nothing and each increase in value switches on more |
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| 14 | messages. See <tt class="filename">ClpMessage.cpp</tt>, |
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| 15 | <tt class="filename">CoinMessage.cpp</tt> and <a href="ch06.html" title="Chapter 6. |
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| 16 | Messages |
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| 17 | ">Chapter 6, <i> |
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| 18 | Messages |
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| 19 | </i></a> to see |
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| 20 | which messages are at which level. A more sophisticated user may wish to |
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| 21 | handle messages in a different way. This is done using |
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| 22 | <tt class="function">passInMessageHandler</tt> with a pointer to a handler of the |
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| 23 | user's own design. The simplest case would be to use the default handler but |
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| 24 | use a constructor which writes to file. The code would be: |
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| 25 | </p><pre class="programlisting"> |
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| 26 | FILE * fp; // assumed open |
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| 27 | CoinMessageHandler handler(fp); |
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| 28 | model.passInMessageHandler(&handler); |
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| 29 | </pre><p> |
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| 30 | A still more sophisticated use would be to write a class derived from |
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| 31 | <tt class="function">CoinMessageHandler</tt> and then override the |
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| 32 | <tt class="function">print</tt> method. Below follows an example which would |
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| 33 | print only a message for optimality (or infeasibility): |
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| 34 | </p><div class="example"><a name="id4772712"></a><p class="title"><b>Example 3.1. Sophisticated message handling</b></p><pre class="programlisting"> |
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| 35 | class DerivedHandler : |
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| 36 | public CoinMessageHandler { |
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| 37 | public: |
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| 38 | virtual int print() ; |
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| 39 | }; |
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| 40 | |
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| 41 | |
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| 42 | int DerivedHandler::print() |
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| 43 | { |
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| 44 | if (currentSource()=="Clp") { |
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| 45 | if (currentMessage().externalNumber()>=0 |
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| 46 | && currentMessage().externalNumber()<4) { |
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| 47 | // finished |
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| 48 | return CoinMessageHandler::print(); // print |
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| 49 | } |
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| 50 | } |
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| 51 | return 0; |
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| 52 | } |
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| 53 | </pre></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ch03s02.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="ch03.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="ch04.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Matrix Classes </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 4. |
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| 54 | More Samples |
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| 55 | </td></tr></table></div></body></html> |
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