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  25 <div class="section boost_icl_function_reference_segmentational_fineness" lang="en">
  26 <div class="titlepage"><div><div><h3 class="title">
  27 <a name="boost_icl.function_reference.segmentational_fineness"></a><a class="link" href="segmentational_fineness.html" title="Segmentational Fineness">Segmentational
  28       Fineness</a>
  29 </h3></div></div></div>
  30 <p>
  31         For overloading tables on infix operators, we need to break down <code class="computeroutput"><a class="link" href="../../boost/icl/interval_set.html" title="Class template interval_set">interval_sets</a></code> and <code class="computeroutput"><a class="link" href="../../boost/icl/interval_map.html" title="Class template interval_map">interval_maps</a></code>
  32         to the specific class templates
  33       </p>
  34 <a name="ph_def_S1"></a><a name="ph_def_S2"></a><a name="ph_def_S3"></a><a name="ph_def_M1"></a><a name="ph_def_M3"></a><div class="informaltable"><table class="table">
  35 <colgroup>
  36 <col>
  37 <col>
  38 <col>
  39 <col>
  40 <col>
  41 <col>
  42 </colgroup>
  43 <thead><tr>
  44 <th>
  45               <p>
  46               </p>
  47               </th>
  48 <th>
  49               <p>
  50               </p>
  51               </th>
  52 <th>
  53               <p>
  54               </p>
  55               </th>
  56 <th>
  57               <p>
  58               </p>
  59               </th>
  60 <th>
  61               <p>
  62               </p>
  63               </th>
  64 <th>
  65               <p>
  66               </p>
  67               </th>
  68 </tr></thead>
  69 <tbody>
  70 <tr>
  71 <td>
  72               <p>
  73                 <span class="bold"><strong>S1</strong></span>
  74               </p>
  75               </td>
  76 <td>
  77               <p>
  78                 <code class="computeroutput"><a class="link" href="../../boost/icl/interval_set.html" title="Class template interval_set">interval_set</a></code>
  79               </p>
  80               </td>
  81 <td>
  82               <p>
  83                 <span class="bold"><strong>S2</strong></span>
  84               </p>
  85               </td>
  86 <td>
  87               <p>
  88                 <code class="computeroutput"><a class="link" href="../../boost/icl/separate_interval_set.html" title="Class template separate_interval_set">separate_interval_set</a></code>
  89               </p>
  90               </td>
  91 <td>
  92               <p>
  93                 <span class="bold"><strong>S3</strong></span>
  94               </p>
  95               </td>
  96 <td>
  97               <p>
  98                 <code class="computeroutput"><a class="link" href="../../boost/icl/split_interval_set.html" title="Class template split_interval_set">split_interval_set</a></code>
  99               </p>
 100               </td>
 101 </tr>
 102 <tr>
 103 <td>
 104               <p>
 105                 <span class="bold"><strong>M1</strong></span>
 106               </p>
 107               </td>
 108 <td>
 109               <p>
 110                 <code class="computeroutput"><a class="link" href="../../boost/icl/interval_map.html" title="Class template interval_map">interval_map</a></code>
 111               </p>
 112               </td>
 113 <td>
 114               <p>
 115               </p>
 116               </td>
 117 <td>
 118               <p>
 119               </p>
 120               </td>
 121 <td>
 122               <p>
 123                 <span class="bold"><strong>M3</strong></span>
 124               </p>
 125               </td>
 126 <td>
 127               <p>
 128                 <code class="computeroutput"><a class="link" href="../../boost/icl/split_interval_map.html" title="Class template split_interval_map">split_interval_map</a></code>
 129               </p>
 130               </td>
 131 </tr>
 132 </tbody>
 133 </table></div>
 134 <p>
 135         choosing <span class="bold"><strong>Si</strong></span> and <span class="bold"><strong>Mi</strong></span>
 136         as placeholders.
 137       </p>
 138 <p>
 139         The indices <span class="bold"><strong>i</strong></span> of <span class="bold"><strong>Si</strong></span>
 140         and <span class="bold"><strong>Mi</strong></span> represent a property called <span class="emphasis"><em><span class="bold"><strong>segmentational fineness</strong></span></em></span> or short <span class="emphasis"><em><span class="bold"><strong>fineness</strong></span></em></span>, which is a <span class="emphasis"><em><span class="bold"><strong>type trait</strong></span></em></span> on interval containers.
 141       </p>
 142 <div class="informaltable"><table class="table">
 143 <colgroup><col></colgroup>
 144 <thead><tr><th>
 145               <p>
 146               </p>
 147               </th></tr></thead>
 148 <tbody>
 149 <tr><td>
 150               <p>
 151                 <code class="computeroutput"><span class="identifier">segmentational_fineness</span><span class="special">&lt;</span></code><span class="bold"><strong>Si</strong></span><code class="computeroutput"><span class="special">&gt;::</span><span class="identifier">value</span></code>
 152                 == <span class="bold"><strong>i</strong></span>
 153               </p>
 154               </td></tr>
 155 <tr><td>
 156               <p>
 157                 <code class="computeroutput"><span class="identifier">segmentational_fineness</span><span class="special">&lt;</span></code><span class="bold"><strong>Mi</strong></span><code class="computeroutput"><span class="special">&gt;::</span><span class="identifier">value</span></code>
 158                 == <span class="bold"><strong>i</strong></span>
 159               </p>
 160               </td></tr>
 161 </tbody>
 162 </table></div>
 163 <p>
 164         Segmentational fineness represents the fact, that for interval containers
 165         holding the same elements, a splitting interval container may contain more
 166         segments as a separating container which in turn may contain more segments
 167         than a joining one. So for an
 168 </p>
 169 <pre class="programlisting"><span class="keyword">operator</span> <span class="special">&gt;</span>
 170 </pre>
 171 <p>
 172         where
 173 </p>
 174 <pre class="programlisting"><span class="identifier">x</span> <span class="special">&gt;</span> <span class="identifier">y</span>   <span class="comment">// means that
 175 </span><span class="identifier">x</span> <span class="identifier">is_finer_than</span> <span class="identifier">y</span>
 176
 177 <span class="comment">// we have
 178 </span>
 179 <span class="identifier">finer</span>                                             <span class="identifier">coarser</span>
 180 <span class="identifier">split_interval_set</span>                           <span class="identifier">interval_set</span>
 181                    <span class="special">&gt;</span> <span class="identifier">separate_interval_set</span> <span class="special">&gt;</span>
 182 <span class="identifier">split_interval_map</span>                           <span class="identifier">interval_map</span>
 183 </pre>
 184 <p>
 185       </p>
 186 <p>
 187         This relation is needed to resolve the instantiation of infix operators e.g.
 188         <code class="computeroutput"><span class="identifier">T</span> <span class="keyword">operator</span>
 189         <span class="special">+</span> <span class="special">(</span><span class="identifier">P</span><span class="special">,</span> <span class="identifier">Q</span><span class="special">)</span></code> for two interval container types <code class="computeroutput"><span class="identifier">P</span></code> and <code class="computeroutput"><span class="identifier">Q</span></code>.
 190         If both <code class="computeroutput"><span class="identifier">P</span></code> and <code class="computeroutput"><span class="identifier">Q</span></code> are candidates for the result type <code class="computeroutput"><span class="identifier">T</span></code>, one of them must be chosen by the compiler.
 191         We choose the type that is segmentational finer as result type <code class="computeroutput"><span class="identifier">T</span></code>. This way we do not loose the <span class="emphasis"><em><span class="bold"><strong>segment information</strong></span></em></span> that is stored in the
 192         <span class="emphasis"><em><span class="bold"><strong>finer</strong></span></em></span> one of the container
 193         types <code class="computeroutput"><span class="identifier">P</span></code> and <code class="computeroutput"><span class="identifier">Q</span></code>.
 194       </p>
 195 <p>
 196
 197 </p>
 198 <pre class="programlisting"><span class="comment">// overload tables for
 199 </span><span class="identifier">T</span> <span class="keyword">operator</span> <span class="special">+</span> <span class="special">(</span><span class="identifier">T</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">P</span><span class="special">&amp;)</span>
 200 <span class="identifier">T</span> <span class="keyword">operator</span> <span class="special">+</span> <span class="special">(</span><span class="keyword">const</span> <span class="identifier">P</span><span class="special">&amp;,</span> <span class="identifier">T</span><span class="special">)</span>
 201
 202 <span class="identifier">element</span> <span class="identifier">containers</span><span class="special">:</span>     <span class="identifier">interval</span> <span class="identifier">containers</span><span class="special">:</span>
 203 <span class="special">+</span>  <span class="special">|</span> <span class="identifier">e</span> <span class="identifier">b</span> <span class="identifier">s</span> <span class="identifier">m</span>            <span class="special">+</span>  <span class="special">|</span> <span class="identifier">e</span>  <span class="identifier">i</span>  <span class="identifier">b</span>  <span class="identifier">p</span>  <span class="identifier">S1</span> <span class="identifier">S2</span> <span class="identifier">S3</span> <span class="identifier">M1</span> <span class="identifier">M3</span>
 204 <span class="special">---+--------</span>            <span class="special">---+---------------------------</span>
 205 <span class="identifier">e</span>  <span class="special">|</span>     <span class="identifier">s</span>              <span class="identifier">e</span>  <span class="special">|</span>             <span class="identifier">S1</span> <span class="identifier">S2</span> <span class="identifier">S3</span>
 206 <span class="identifier">b</span>  <span class="special">|</span>       <span class="identifier">m</span>            <span class="identifier">i</span>  <span class="special">|</span>             <span class="identifier">S1</span> <span class="identifier">S2</span> <span class="identifier">S3</span>
 207 <span class="identifier">s</span>  <span class="special">|</span> <span class="identifier">s</span>   <span class="identifier">s</span>              <span class="identifier">b</span>  <span class="special">|</span>                      <span class="identifier">M1</span> <span class="identifier">M3</span>
 208 <span class="identifier">m</span>  <span class="special">|</span>   <span class="identifier">m</span>   <span class="identifier">m</span>            <span class="identifier">p</span>  <span class="special">|</span>                      <span class="identifier">M1</span> <span class="identifier">M3</span>
 209                         <span class="identifier">S1</span> <span class="special">|</span> <span class="identifier">S1</span> <span class="identifier">S1</span>       <span class="identifier">S1</span> <span class="identifier">S2</span> <span class="identifier">S3</span>
 210                         <span class="identifier">S2</span> <span class="special">|</span> <span class="identifier">S2</span> <span class="identifier">S2</span>       <span class="identifier">S2</span> <span class="identifier">S2</span> <span class="identifier">S3</span>
 211                         <span class="identifier">S3</span> <span class="special">|</span> <span class="identifier">S3</span> <span class="identifier">S3</span>       <span class="identifier">S3</span> <span class="identifier">S3</span> <span class="identifier">S3</span>
 212                         <span class="identifier">M1</span> <span class="special">|</span>       <span class="identifier">M1</span> <span class="identifier">M1</span>          <span class="identifier">M1</span> <span class="identifier">M3</span>
 213                         <span class="identifier">M3</span> <span class="special">|</span>       <span class="identifier">M3</span> <span class="identifier">M3</span>          <span class="identifier">M3</span> <span class="identifier">M3</span>
 214 </pre>
 215 <p>
 216       </p>
 217 <p>
 218         So looking up a type combination for e.g. <code class="computeroutput"><span class="identifier">T</span>
 219         <span class="keyword">operator</span> <span class="special">+</span>
 220         <span class="special">(</span><span class="identifier">interval_map</span><span class="special">,</span> <span class="identifier">split_interval_map</span><span class="special">)</span></code> which is equivalent to <code class="computeroutput"><span class="identifier">T</span>
 221         <span class="keyword">operator</span> <span class="special">+</span>
 222         <span class="special">(</span><span class="identifier">M1</span><span class="special">,</span> <span class="identifier">M3</span><span class="special">)</span></code>
 223         we find for row type <code class="computeroutput"><span class="identifier">M1</span></code> and
 224         column type <code class="computeroutput"><span class="identifier">M3</span></code> that <code class="computeroutput"><span class="identifier">M3</span></code> will be assigned as result type, because
 225         <code class="computeroutput"><span class="identifier">M3</span></code> is finer than <code class="computeroutput"><span class="identifier">M1</span></code>. So this type combination will result
 226         in choosing this
 227 </p>
 228 <pre class="programlisting"><span class="identifier">split_interval_map</span> <span class="keyword">operator</span> <span class="special">+</span> <span class="special">(</span><span class="keyword">const</span> <span class="identifier">interval_map</span><span class="special">&amp;,</span> <span class="identifier">split_interval_map</span><span class="special">)</span>
 229 </pre>
 230 <p>
 231         implementation by the compiler.
 232       </p>
 233 </div>
 234 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 235 <td align="left"></td>
 236 <td align="right"><div class="copyright-footer">Copyright &#169; 2007 -2010 Joachim Faulhaber<br>Copyright &#169; 1999 -2006 Cortex Software GmbH<p>
 237         Distributed under the Boost Software License, Version 1.0. (See accompanying
 238         file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
 239       </p>
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