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324 lines
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<title>interval<R></title>
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<td valign="top"><img href="index.html" height="164px" src="pre-boost.jpg" alt="Library Documentation Index"></td>
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<td><h2>Safe Numerics</h2></td>
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<div class="section">
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<div class="titlepage"><div><div><h3 class="title">
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<a name="safe_numerics.interval"></a>interval<R></h3></div></div></div>
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<div class="toc"><dl class="toc">
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<dt><span class="section"><a href="interval.html#idm130202132352">Description</a></span></dt>
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<dt><span class="section"><a href="interval.html#idm130202129408">Template Parameters</a></span></dt>
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<dt><span class="section"><a href="interval.html#idm130202126048">Notation</a></span></dt>
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<dt><span class="section"><a href="interval.html#idm130202108592">Associated Types</a></span></dt>
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<dt><span class="section"><a href="interval.html#idm130202102752">Valid Expressions</a></span></dt>
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<dt><span class="section"><a href="interval.html#idm130202023104">Example of use</a></span></dt>
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<dt><span class="section"><a href="interval.html#idm130201930272">Header</a></span></dt>
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</dl></div>
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<div class="section">
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<div class="titlepage"><div><div><h4 class="title">
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<a name="idm130202132352"></a>Description</h4></div></div></div>
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<p>A closed arithmetic interval represented by a pair of elements of
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type R. In principle, one should be able to use Boost.Interval library for
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this. But the functions in this library are not <code class="computeroutput">constexpr</code>.
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Also, this Boost.Interval is more complex and does not support certain
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operations such bit operations. Perhaps some time in the future,
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Boost.Interval will be used instead of this <code class="computeroutput">interval<R></code>
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type.</p>
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</div>
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<div class="section">
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<div class="titlepage"><div><div><h4 class="title">
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<a name="idm130202129408"></a>Template Parameters</h4></div></div></div>
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<p>R must model the type requirements of <a class="link" href="numeric.html" title="Numeric<T>">Numeric</a>. Note this in principle
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includes any numeric type including floating point numbers and instances
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of <a class="link" href="checked_result.html" title="checked_result<R>"><code class="computeroutput">checked_result<R></code></a>.</p>
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</div>
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<div class="section">
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<div class="titlepage"><div><div><h4 class="title">
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<a name="idm130202126048"></a>Notation</h4></div></div></div>
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<div class="informaltable"><table class="table">
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<colgroup>
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<col align="left">
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<col align="left">
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</colgroup>
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<thead><tr>
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<th align="left">Symbol</th>
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<th align="left">Description</th>
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</tr></thead>
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<tbody>
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<tr>
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<td align="left"><code class="computeroutput">I</code></td>
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<td align="left">An interval type</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">i, j</code></td>
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<td align="left">An instance of interval type</td>
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<tr>
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<td align="left"><code class="computeroutput">R</code></td>
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<td align="left">Numeric types which can be used to make an interval</td>
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<tr>
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<td align="left"><code class="computeroutput">r</code></td>
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<td align="left">An instance of type R</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">p</code></td>
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<td align="left">An instance of std::pair<R, R></td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">l, u</code></td>
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<td align="left">Lowermost and uppermost values in an interval</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">os</code></td>
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<td align="left">std::basic_ostream<class CharT, class Traits =
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std::char_traits<CharT>></td>
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</tr>
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</tbody>
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</table></div>
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</div>
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<div class="section">
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<div class="titlepage"><div><div><h4 class="title">
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<a name="idm130202108592"></a>Associated Types</h4></div></div></div>
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<div class="informaltable"><table class="table">
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<colgroup>
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<col align="left">
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<col align="left">
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</colgroup>
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<tbody><tr>
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<td align="left"><a class="link" href="checked_result.html" title="checked_result<R>"><code class="computeroutput">checked_result</code></a></td>
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<td align="left">holds either the result of an operation or information as
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to why it failed</td>
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</tr></tbody>
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</table></div>
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</div>
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<div class="section">
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<div class="titlepage"><div><div><h4 class="title">
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<a name="idm130202102752"></a>Valid Expressions</h4></div></div></div>
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<p>Note that all expressions are constexpr.</p>
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<div class="informaltable"><table class="table">
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<colgroup>
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<col align="left">
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<col align="left">
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<col align="left">
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</colgroup>
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<thead><tr>
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<th align="left">Expression</th>
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<th align="left">Return Type</th>
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<th align="left">Semantics</th>
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</tr></thead>
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<tbody>
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<tr>
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<td align="left"><code class="computeroutput">interval<R>(l, u)</code></td>
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<td align="left"><code class="computeroutput">interval<R></code></td>
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<td align="left">construct a new interval from a pair of limits</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">interval<R>(p)</code></td>
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<td align="left"><code class="computeroutput">interval<R></code></td>
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<td align="left">construct a new interval from a pair of limits</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">interval<R>(i)</code></td>
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<td align="left"><code class="computeroutput">interval<R></code></td>
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<td align="left">copy constructor</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">make_interval<R>()</code></td>
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<td align="left"><code class="computeroutput">interval<R></code></td>
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<td align="left">return new interval with
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std::numric_limits<R>::min() and
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std::numric_limits<R>::max()</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">make_interval<R>(const R
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&r)</code></td>
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<td align="left"><code class="computeroutput">interval<R></code></td>
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<td align="left">return new interval with
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std::numric_limits<R>::min() and
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std::numric_limits<R>::max()</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">i.l</code></td>
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<td align="left"><code class="computeroutput">R</code></td>
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<td align="left">lowermost value in the interval i</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">i.u</code></td>
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<td align="left"><code class="computeroutput">R</code></td>
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<td align="left">uppermost value in the interval i</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">i.includes(j)</code></td>
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<td align="left"><code class="computeroutput">boost::logic::tribool</code></td>
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<td align="left">return true if interval i includes interval j</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">i.excludes(j)</code></td>
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<td align="left"><code class="computeroutput">boost::logic::tribool</code></td>
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<td align="left">return true if interval i includes interval j</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">i.includes(t)</code></td>
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<td align="left"><code class="computeroutput">bool</code></td>
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<td align="left">return true if interval i includes value t</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">i.excludes(t)</code></td>
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<td align="left"><code class="computeroutput">bool</code></td>
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<td align="left">return true if interval i includes value t</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">i + j</code></td>
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<td align="left"><code class="computeroutput">interval<R></code></td>
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<td align="left">add two intervals and return the result</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">i - j</code></td>
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<td align="left"><code class="computeroutput">interval<R></code></td>
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<td align="left">subtract two intervals and return the result</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">i * j</code></td>
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<td align="left"><code class="computeroutput">interval<R></code></td>
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<td align="left">multiply two intervals and return the result</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">i / j</code></td>
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<td align="left"><code class="computeroutput">interval<R></code></td>
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<td align="left">divide one interval by another and return the
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result</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">i % j</code></td>
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<td align="left"><code class="computeroutput">interval<R></code></td>
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<td align="left">calculate modulus of one interval by another and return
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the result</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">i << j</code></td>
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<td align="left"><code class="computeroutput">interval<R></code></td>
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<td align="left">calculate the range that would result from shifting one
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interval by another</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">i >> j</code></td>
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<td align="left"><code class="computeroutput">interval<R></code></td>
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<td align="left">calculate the range that would result from shifting one
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interval by another</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">i | j</code></td>
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<td align="left"><code class="computeroutput">interval<R></code></td>
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<td align="left">range of values which can result from applying | to any
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pair of operands from I and j</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">i & j</code></td>
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<td align="left"><code class="computeroutput">interval<R></code></td>
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<td align="left">range of values which can result from applying & to
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any pair of operands from I and j</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">i ^ j</code></td>
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<td align="left"><code class="computeroutput">interval<R></code></td>
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<td align="left">range of values which can result from applying ^ to any
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pair of operands from I and j</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">t < u</code></td>
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<td align="left"><code class="computeroutput">boost::logic::tribool</code></td>
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<td align="left">true if every element in t is less than every element in
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u</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">t > u</code></td>
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<td align="left"><code class="computeroutput">boost::logic::tribool</code></td>
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<td align="left">true if every element in t is greater than every element
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in u</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">t <= u</code></td>
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<td align="left"><code class="computeroutput">boost::logic::tribool</code></td>
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<td align="left">true if every element in t is less than or equal to every
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element in u</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">t >= u</code></td>
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<td align="left"><code class="computeroutput">boost::logic::tribool</code></td>
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<td align="left">true if every element in t is greater than or equal to
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every element in u</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">t == u</code></td>
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<td align="left"><code class="computeroutput">bool</code></td>
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<td align="left">true if limits are equal</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">t != u</code></td>
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<td align="left"><code class="computeroutput">bool</code></td>
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<td align="left">true if limits are not equal</td>
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</tr>
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<tr>
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<td align="left"><code class="computeroutput">os << i</code></td>
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<td align="left"><code class="computeroutput">os &</code></td>
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<td align="left">print interval to output stream</td>
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</tr>
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</tbody>
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</table></div>
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</div>
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<div class="section">
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<div class="titlepage"><div><div><h4 class="title">
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<a name="idm130202023104"></a>Example of use</h4></div></div></div>
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<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">iostream</span><span class="special">></span>
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<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">cstdint</span><span class="special">></span>
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<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">cassert</span><span class="special">></span>
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<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">numeric</span><span class="special">/</span><span class="identifier">safe_numerics</span><span class="special">/</span><span class="identifier">interval</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
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<span class="keyword">int</span> <span class="identifier">main</span><span class="special">(</span><span class="special">)</span><span class="special">{</span>
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<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"test1"</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
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<span class="identifier">interval</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">int16_t</span><span class="special">></span> <span class="identifier">x</span> <span class="special">=</span> <span class="special">{</span><span class="special">-</span><span class="number">64</span><span class="special">,</span> <span class="number">63</span><span class="special">}</span><span class="special">;</span>
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<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"x = "</span> <span class="special"><<</span> <span class="identifier">x</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
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<span class="identifier">interval</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">int16_t</span><span class="special">></span> <span class="identifier">y</span><span class="special">(</span><span class="special">-</span><span class="number">128</span><span class="special">,</span> <span class="number">126</span><span class="special">)</span><span class="special">;</span>
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<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"y = "</span> <span class="special"><<</span> <span class="identifier">y</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
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<span class="identifier">assert</span><span class="special">(</span><span class="keyword">static_cast</span><span class="special"><</span><span class="identifier">interval</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">int16_t</span><span class="special">>></span><span class="special">(</span><span class="identifier">add</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">int16_t</span><span class="special">></span><span class="special">(</span><span class="identifier">x</span><span class="special">,</span><span class="identifier">x</span><span class="special">)</span><span class="special">)</span> <span class="special">==</span> <span class="identifier">y</span><span class="special">)</span><span class="special">;</span>
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<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"x + x ="</span> <span class="special"><<</span> <span class="identifier">add</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">int16_t</span><span class="special">></span><span class="special">(</span><span class="identifier">x</span><span class="special">,</span> <span class="identifier">x</span><span class="special">)</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
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<span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"x - x = "</span> <span class="special"><<</span> <span class="identifier">subtract</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">int16_t</span><span class="special">></span><span class="special">(</span><span class="identifier">x</span><span class="special">,</span> <span class="identifier">x</span><span class="special">)</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
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<span class="keyword">return</span> <span class="number">0</span><span class="special">;</span>
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<span class="special">}</span></pre>
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</div>
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<div class="section">
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<div class="titlepage"><div><div><h4 class="title">
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<a name="idm130201930272"></a>Header</h4></div></div></div>
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<p><code class="computeroutput">#include
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<boost/numeric/safe_numerics/interval.hpp></code></p>
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</div>
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</div>
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<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
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<td align="left"></td>
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<td align="right"><div class="copyright-footer">Copyright © 2012-2018 Robert Ramey<p><a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">Subject to Boost
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Software License</a></p>
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</div></td>
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</tr></table>
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<hr>
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</body>
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</html>
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