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<title>Setting Policies at Namespace or Translation Unit Scope</title>
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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="math_toolkit.pol_tutorial.namespace_policies"></a><a class="link" href="namespace_policies.html" title="Setting Policies at Namespace or Translation Unit Scope">Setting
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Policies at Namespace or Translation Unit Scope</a>
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</h3></div></div></div>
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<p>
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Sometimes what you want to do is just change a set of policies within the
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current scope: <span class="bold"><strong>the one thing you should not do in this
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situation is use the configuration macros</strong></span>, as this can lead to
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"One Definition Rule" violations. Instead this library provides
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a pair of macros especially for this purpose.
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</p>
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<p>
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Let's consider the special functions first: we can declare a set of forwarding
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functions that all use a specific policy using the macro BOOST_MATH_DECLARE_SPECIAL_FUNCTIONS(<span class="emphasis"><em>Policy</em></span>).
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This macro should be used either inside a unique namespace set aside for
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the purpose (for example, a C namespace for a C-style policy), or an unnamed
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namespace if you just want the functions visible in global scope for the
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current file only.
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</p>
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<p>
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Suppose we want <code class="computeroutput"><span class="identifier">C</span><span class="special">::</span><span class="identifier">foo</span><span class="special">()</span></code> to
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behave in a C-compatible way and set <code class="computeroutput"><span class="special">::</span><span class="identifier">errno</span></code> on error rather than throwing any
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exceptions.
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</p>
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<p>
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We'll begin by including the needed header for our function:
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</p>
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<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">math</span><span class="special">/</span><span class="identifier">special_functions</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
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<span class="comment">//using boost::math::tgamma; // Not needed because using C::tgamma.</span>
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</pre>
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<p>
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Open up the "C" namespace that we'll use for our functions, and
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define the policy type we want: in this case a C-style one that sets ::errno
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and returns a standard value, rather than throwing exceptions.
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</p>
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<p>
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Any policies we don't specify here will inherit the defaults.
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</p>
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<pre class="programlisting"><span class="keyword">namespace</span> <span class="identifier">C</span>
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<span class="special">{</span> <span class="comment">// To hold our C-style policy.</span>
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<span class="comment">//using namespace boost::math::policies; or explicitly:</span>
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<span class="keyword">using</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">math</span><span class="special">::</span><span class="identifier">policies</span><span class="special">::</span><span class="identifier">policy</span><span class="special">;</span>
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<span class="keyword">using</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">math</span><span class="special">::</span><span class="identifier">policies</span><span class="special">::</span><span class="identifier">domain_error</span><span class="special">;</span>
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<span class="keyword">using</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">math</span><span class="special">::</span><span class="identifier">policies</span><span class="special">::</span><span class="identifier">pole_error</span><span class="special">;</span>
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<span class="keyword">using</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">math</span><span class="special">::</span><span class="identifier">policies</span><span class="special">::</span><span class="identifier">overflow_error</span><span class="special">;</span>
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<span class="keyword">using</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">math</span><span class="special">::</span><span class="identifier">policies</span><span class="special">::</span><span class="identifier">evaluation_error</span><span class="special">;</span>
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<span class="keyword">using</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">math</span><span class="special">::</span><span class="identifier">policies</span><span class="special">::</span><span class="identifier">errno_on_error</span><span class="special">;</span>
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<span class="keyword">typedef</span> <span class="identifier">policy</span><span class="special"><</span>
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<span class="identifier">domain_error</span><span class="special"><</span><span class="identifier">errno_on_error</span><span class="special">>,</span>
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<span class="identifier">pole_error</span><span class="special"><</span><span class="identifier">errno_on_error</span><span class="special">>,</span>
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<span class="identifier">overflow_error</span><span class="special"><</span><span class="identifier">errno_on_error</span><span class="special">>,</span>
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<span class="identifier">evaluation_error</span><span class="special"><</span><span class="identifier">errno_on_error</span><span class="special">></span>
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<span class="special">></span> <span class="identifier">c_policy</span><span class="special">;</span>
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</pre>
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<p>
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All we need do now is invoke the BOOST_MATH_DECLARE_SPECIAL_FUNCTIONS macro
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passing our policy type c_policy as the single argument:
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</p>
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<pre class="programlisting"><span class="identifier">BOOST_MATH_DECLARE_SPECIAL_FUNCTIONS</span><span class="special">(</span><span class="identifier">c_policy</span><span class="special">)</span>
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<span class="special">}</span> <span class="comment">// close namespace C</span>
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</pre>
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<p>
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We now have a set of forwarding functions defined in namespace C that all
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look something like this:
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</p>
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<pre class="programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">RealType</span><span class="special">></span>
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<span class="keyword">inline</span> <span class="keyword">typename</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">math</span><span class="special">::</span><span class="identifier">tools</span><span class="special">::</span><span class="identifier">promote_args</span><span class="special"><</span><span class="identifier">RT</span><span class="special">>::</span><span class="identifier">type</span>
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<span class="identifier">tgamma</span><span class="special">(</span><span class="identifier">RT</span> <span class="identifier">z</span><span class="special">)</span>
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<span class="special">{</span>
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<span class="keyword">return</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">math</span><span class="special">::</span><span class="identifier">tgamma</span><span class="special">(</span><span class="identifier">z</span><span class="special">,</span> <span class="identifier">c_policy</span><span class="special">());</span>
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<span class="special">}</span>
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</pre>
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<p>
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So that when we call <code class="computeroutput"><span class="identifier">C</span><span class="special">::</span><span class="identifier">tgamma</span><span class="special">(</span><span class="identifier">z</span><span class="special">)</span></code>, we
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really end up calling <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">math</span><span class="special">::</span><span class="identifier">tgamma</span><span class="special">(</span><span class="identifier">z</span><span class="special">,</span>
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<span class="identifier">C</span><span class="special">::</span><span class="identifier">c_policy</span><span class="special">())</span></code>:
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</p>
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<pre class="programlisting"><span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span>
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<span class="special">{</span>
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<span class="identifier">errno</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span>
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<span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"Result of tgamma(30000) is: "</span>
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<span class="special"><<</span> <span class="identifier">C</span><span class="special">::</span><span class="identifier">tgamma</span><span class="special">(</span><span class="number">30000</span><span class="special">)</span> <span class="special"><<</span> <span class="identifier">endl</span><span class="special">;</span> <span class="comment">// Note using C::tgamma</span>
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<span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"errno = "</span> <span class="special"><<</span> <span class="identifier">errno</span> <span class="special"><<</span> <span class="identifier">endl</span><span class="special">;</span> <span class="comment">// errno = 34</span>
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<span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"Result of tgamma(-10) is: "</span>
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<span class="special"><<</span> <span class="identifier">C</span><span class="special">::</span><span class="identifier">tgamma</span><span class="special">(-</span><span class="number">10</span><span class="special">)</span> <span class="special"><<</span> <span class="identifier">endl</span><span class="special">;</span>
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<span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"errno = "</span> <span class="special"><<</span> <span class="identifier">errno</span> <span class="special"><<</span> <span class="identifier">endl</span><span class="special">;</span> <span class="comment">// errno = 33, overwriting previous value of 34.</span>
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<span class="special">}</span>
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</pre>
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<p>
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Which outputs:
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</p>
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<pre class="programlisting">Result of C::tgamma(30000) is: 1.#INF
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errno = 34
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Result of C::tgamma(-10) is: 1.#QNAN
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errno = 33
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</pre>
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<p>
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This mechanism is particularly useful when we want to define a project-wide
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policy, and don't want to modify the Boost source, or to set project wide
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build macros (possibly fragile and easy to forget).
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</p>
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<p>
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The same mechanism works well at file scope as well, by using an unnamed
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namespace, we can ensure that these declarations don't conflict with any
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alternate policies present in other translation units:
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</p>
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<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">math</span><span class="special">/</span><span class="identifier">special_functions</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
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<span class="comment">// using boost::math::tgamma; // Would create an ambiguity between</span>
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<span class="comment">// 'double boost::math::tgamma<int>(T)' and</span>
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<span class="comment">// 'double 'anonymous-namespace'::tgamma<int>(RT)'.</span>
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<span class="keyword">namespace</span> <span class="identifier">mymath</span>
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<span class="special">{</span> <span class="comment">// unnamed</span>
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<span class="keyword">using</span> <span class="keyword">namespace</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">math</span><span class="special">::</span><span class="identifier">policies</span><span class="special">;</span>
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<span class="keyword">typedef</span> <span class="identifier">policy</span><span class="special"><</span>
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<span class="identifier">domain_error</span><span class="special"><</span><span class="identifier">errno_on_error</span><span class="special">>,</span>
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<span class="identifier">pole_error</span><span class="special"><</span><span class="identifier">errno_on_error</span><span class="special">>,</span>
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<span class="identifier">overflow_error</span><span class="special"><</span><span class="identifier">errno_on_error</span><span class="special">>,</span>
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<span class="identifier">evaluation_error</span><span class="special"><</span><span class="identifier">errno_on_error</span><span class="special">></span>
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<span class="special">></span> <span class="identifier">c_policy</span><span class="special">;</span>
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<span class="identifier">BOOST_MATH_DECLARE_SPECIAL_FUNCTIONS</span><span class="special">(</span><span class="identifier">c_policy</span><span class="special">)</span>
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</pre>
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<p>
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So that when we call <code class="computeroutput"><span class="identifier">mymath</span><span class="special">::</span><span class="identifier">tgamma</span><span class="special">(</span><span class="identifier">z</span><span class="special">)</span></code>,
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we really end up calling <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">math</span><span class="special">::</span><span class="identifier">tgamma</span><span class="special">(</span><span class="identifier">z</span><span class="special">,</span>
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<span class="identifier">anonymous</span><span class="special">-</span><span class="keyword">namespace</span><span class="special">::</span><span class="identifier">c_policy</span><span class="special">())</span></code>.
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</p>
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<pre class="programlisting"><span class="special">}</span> <span class="comment">// close unnamed namespace</span>
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<span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span>
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<span class="special">{</span>
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<span class="identifier">errno</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span>
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<span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"Result of tgamma(30000) is: "</span>
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<span class="special"><<</span> <span class="identifier">mymath</span><span class="special">::</span><span class="identifier">tgamma</span><span class="special">(</span><span class="number">30000</span><span class="special">)</span> <span class="special"><<</span> <span class="identifier">endl</span><span class="special">;</span>
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<span class="comment">// tgamma in unnamed namespace in this translation unit (file) only.</span>
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<span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"errno = "</span> <span class="special"><<</span> <span class="identifier">errno</span> <span class="special"><<</span> <span class="identifier">endl</span><span class="special">;</span>
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<span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"Result of tgamma(-10) is: "</span>
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<span class="special"><<</span> <span class="identifier">mymath</span><span class="special">::</span><span class="identifier">tgamma</span><span class="special">(-</span><span class="number">10</span><span class="special">)</span> <span class="special"><<</span> <span class="identifier">endl</span><span class="special">;</span>
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<span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"errno = "</span> <span class="special"><<</span> <span class="identifier">errno</span> <span class="special"><<</span> <span class="identifier">endl</span><span class="special">;</span>
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<span class="comment">// Default tgamma policy would throw an exception, and abort.</span>
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<span class="special">}</span>
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</pre>
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<p>
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Handling policies for the statistical distributions is very similar except
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that now the macro BOOST_MATH_DECLARE_DISTRIBUTIONS accepts two parameters:
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the floating point type to use, and the policy type to apply. For example:
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</p>
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<pre class="programlisting"><span class="identifier">BOOST_MATH_DECLARE_DISTRIBUTIONS</span><span class="special">(</span><span class="keyword">double</span><span class="special">,</span> <span class="identifier">my_policy</span><span class="special">)</span>
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</pre>
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<p>
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Results a set of typedefs being defined like this:
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</p>
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<pre class="programlisting"><span class="keyword">typedef</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">math</span><span class="special">::</span><span class="identifier">normal_distribution</span><span class="special"><</span><span class="keyword">double</span><span class="special">,</span> <span class="identifier">my_policy</span><span class="special">></span> <span class="identifier">normal</span><span class="special">;</span>
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</pre>
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<p>
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The name of each typedef is the same as the name of the distribution class
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template, but without the "_distribution" suffix.
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</p>
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<p>
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Suppose we want a set of distributions to behave as follows:
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</p>
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<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
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<li class="listitem">
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Return infinity on overflow, rather than throwing an exception.
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</li>
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<li class="listitem">
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Don't perform any promotion from double to long double internally.
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</li>
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<li class="listitem">
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Return the closest integer result from the quantiles of discrete distributions.
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</li>
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</ul></div>
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<p>
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We'll begin by including the needed header for all the distributions:
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</p>
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<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">math</span><span class="special">/</span><span class="identifier">distributions</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
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</pre>
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<p>
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Open up an appropriate namespace, calling it <code class="computeroutput"><span class="identifier">my_distributions</span></code>,
|
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for our distributions, and define the policy type we want. Any policies we
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don't specify here will inherit the defaults:
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</p>
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<pre class="programlisting"><span class="keyword">namespace</span> <span class="identifier">my_distributions</span>
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<span class="special">{</span>
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<span class="keyword">using</span> <span class="keyword">namespace</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">math</span><span class="special">::</span><span class="identifier">policies</span><span class="special">;</span>
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<span class="comment">// using boost::math::policies::errno_on_error; // etc.</span>
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<span class="keyword">typedef</span> <span class="identifier">policy</span><span class="special"><</span>
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<span class="comment">// return infinity and set errno rather than throw:</span>
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<span class="identifier">overflow_error</span><span class="special"><</span><span class="identifier">errno_on_error</span><span class="special">>,</span>
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<span class="comment">// Don't promote double -> long double internally:</span>
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<span class="identifier">promote_double</span><span class="special"><</span><span class="keyword">false</span><span class="special">>,</span>
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<span class="comment">// Return the closest integer result for discrete quantiles:</span>
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<span class="identifier">discrete_quantile</span><span class="special"><</span><span class="identifier">integer_round_nearest</span><span class="special">></span>
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<span class="special">></span> <span class="identifier">my_policy</span><span class="special">;</span>
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</pre>
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<p>
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All we need do now is invoke the BOOST_MATH_DECLARE_DISTRIBUTIONS macro passing
|
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the floating point type <code class="computeroutput"><span class="keyword">double</span></code>
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and policy types <code class="computeroutput"><span class="identifier">my_policy</span></code>
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as arguments:
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</p>
|
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<pre class="programlisting"><span class="identifier">BOOST_MATH_DECLARE_DISTRIBUTIONS</span><span class="special">(</span><span class="keyword">double</span><span class="special">,</span> <span class="identifier">my_policy</span><span class="special">)</span>
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<span class="special">}</span> <span class="comment">// close namespace my_namespace</span>
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</pre>
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<p>
|
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We now have a set of typedefs defined in namespace my_distributions that
|
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all look something like this:
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</p>
|
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<pre class="programlisting"><span class="keyword">typedef</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">math</span><span class="special">::</span><span class="identifier">normal_distribution</span><span class="special"><</span><span class="keyword">double</span><span class="special">,</span> <span class="identifier">my_policy</span><span class="special">></span> <span class="identifier">normal</span><span class="special">;</span>
|
|
<span class="keyword">typedef</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">math</span><span class="special">::</span><span class="identifier">cauchy_distribution</span><span class="special"><</span><span class="keyword">double</span><span class="special">,</span> <span class="identifier">my_policy</span><span class="special">></span> <span class="identifier">cauchy</span><span class="special">;</span>
|
|
<span class="keyword">typedef</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">math</span><span class="special">::</span><span class="identifier">gamma_distribution</span><span class="special"><</span><span class="keyword">double</span><span class="special">,</span> <span class="identifier">my_policy</span><span class="special">></span> <span class="identifier">gamma</span><span class="special">;</span>
|
|
<span class="comment">// etc</span>
|
|
</pre>
|
|
<p>
|
|
So that when we use my_distributions::normal we really end up using <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">math</span><span class="special">::</span><span class="identifier">normal_distribution</span><span class="special"><</span><span class="keyword">double</span><span class="special">,</span> <span class="identifier">my_policy</span><span class="special">></span></code>:
|
|
</p>
|
|
<pre class="programlisting"><span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span>
|
|
<span class="special">{</span>
|
|
<span class="comment">// Construct distribution with something we know will overflow</span>
|
|
<span class="comment">// (using double rather than if promoted to long double):</span>
|
|
<span class="identifier">my_distributions</span><span class="special">::</span><span class="identifier">normal</span> <span class="identifier">norm</span><span class="special">(</span><span class="number">10</span><span class="special">,</span> <span class="number">2</span><span class="special">);</span>
|
|
|
|
<span class="identifier">errno</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span>
|
|
<span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"Result of quantile(norm, 0) is: "</span>
|
|
<span class="special"><<</span> <span class="identifier">quantile</span><span class="special">(</span><span class="identifier">norm</span><span class="special">,</span> <span class="number">0</span><span class="special">)</span> <span class="special"><<</span> <span class="identifier">endl</span><span class="special">;</span> <span class="comment">// -infinity.</span>
|
|
<span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"errno = "</span> <span class="special"><<</span> <span class="identifier">errno</span> <span class="special"><<</span> <span class="identifier">endl</span><span class="special">;</span>
|
|
<span class="identifier">errno</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span>
|
|
<span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"Result of quantile(norm, 1) is: "</span>
|
|
<span class="special"><<</span> <span class="identifier">quantile</span><span class="special">(</span><span class="identifier">norm</span><span class="special">,</span> <span class="number">1</span><span class="special">)</span> <span class="special"><<</span> <span class="identifier">endl</span><span class="special">;</span> <span class="comment">// +infinity.</span>
|
|
<span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"errno = "</span> <span class="special"><<</span> <span class="identifier">errno</span> <span class="special"><<</span> <span class="identifier">endl</span><span class="special">;</span>
|
|
|
|
<span class="comment">// Now try a discrete distribution.</span>
|
|
<span class="identifier">my_distributions</span><span class="special">::</span><span class="identifier">binomial</span> <span class="identifier">binom</span><span class="special">(</span><span class="number">20</span><span class="special">,</span> <span class="number">0.25</span><span class="special">);</span>
|
|
<span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"Result of quantile(binom, 0.05) is: "</span>
|
|
<span class="special"><<</span> <span class="identifier">quantile</span><span class="special">(</span><span class="identifier">binom</span><span class="special">,</span> <span class="number">0.05</span><span class="special">)</span> <span class="special"><<</span> <span class="identifier">endl</span><span class="special">;</span> <span class="comment">// To check we get integer results.</span>
|
|
<span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"Result of quantile(complement(binom, 0.05)) is: "</span>
|
|
<span class="special"><<</span> <span class="identifier">quantile</span><span class="special">(</span><span class="identifier">complement</span><span class="special">(</span><span class="identifier">binom</span><span class="special">,</span> <span class="number">0.05</span><span class="special">))</span> <span class="special"><<</span> <span class="identifier">endl</span><span class="special">;</span>
|
|
<span class="special">}</span>
|
|
</pre>
|
|
<p>
|
|
Which outputs:
|
|
</p>
|
|
<pre class="programlisting">Result of quantile(norm, 0) is: -1.#INF
|
|
errno = 34
|
|
Result of quantile(norm, 1) is: 1.#INF
|
|
errno = 34
|
|
Result of quantile(binom, 0.05) is: 1
|
|
Result of quantile(complement(binom, 0.05)) is: 8
|
|
</pre>
|
|
<p>
|
|
This mechanism is particularly useful when we want to define a project-wide
|
|
policy, and don't want to modify the Boost source or set project wide build
|
|
macros (possibly fragile and easy to forget).
|
|
</p>
|
|
<div class="note"><table border="0" summary="Note">
|
|
<tr>
|
|
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../../../doc/src/images/note.png"></td>
|
|
<th align="left">Note</th>
|
|
</tr>
|
|
<tr><td align="left" valign="top"><p>
|
|
There is an important limitation to note: you can *not use the macros BOOST_MATH_DECLARE_DISTRIBUTIONS
|
|
and BOOST_MATH_DECLARE_SPECIAL_FUNCTIONS <span class="emphasis"><em>in the same namespace</em></span>*,
|
|
as doing so creates ambiguities between functions and distributions of
|
|
the same name.
|
|
</p></td></tr>
|
|
</table></div>
|
|
<p>
|
|
As before, the same mechanism works well at file scope as well: by using
|
|
an unnamed namespace, we can ensure that these declarations don't conflict
|
|
with any alternate policies present in other translation units:
|
|
</p>
|
|
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">math</span><span class="special">/</span><span class="identifier">distributions</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> <span class="comment">// All distributions.</span>
|
|
<span class="comment">// using boost::math::normal; // Would create an ambiguity between</span>
|
|
<span class="comment">// boost::math::normal_distribution<RealType> boost::math::normal and</span>
|
|
<span class="comment">// 'anonymous-namespace'::normal'.</span>
|
|
|
|
<span class="keyword">namespace</span>
|
|
<span class="special">{</span> <span class="comment">// anonymous or unnamed (rather than named as in policy_eg_6.cpp).</span>
|
|
|
|
<span class="keyword">using</span> <span class="keyword">namespace</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">math</span><span class="special">::</span><span class="identifier">policies</span><span class="special">;</span>
|
|
<span class="comment">// using boost::math::policies::errno_on_error; // etc.</span>
|
|
<span class="keyword">typedef</span> <span class="identifier">policy</span><span class="special"><</span>
|
|
<span class="comment">// return infinity and set errno rather than throw:</span>
|
|
<span class="identifier">overflow_error</span><span class="special"><</span><span class="identifier">errno_on_error</span><span class="special">>,</span>
|
|
<span class="comment">// Don't promote double -> long double internally:</span>
|
|
<span class="identifier">promote_double</span><span class="special"><</span><span class="keyword">false</span><span class="special">>,</span>
|
|
<span class="comment">// Return the closest integer result for discrete quantiles:</span>
|
|
<span class="identifier">discrete_quantile</span><span class="special"><</span><span class="identifier">integer_round_nearest</span><span class="special">></span>
|
|
<span class="special">></span> <span class="identifier">my_policy</span><span class="special">;</span>
|
|
|
|
<span class="identifier">BOOST_MATH_DECLARE_DISTRIBUTIONS</span><span class="special">(</span><span class="keyword">double</span><span class="special">,</span> <span class="identifier">my_policy</span><span class="special">)</span>
|
|
|
|
<span class="special">}</span> <span class="comment">// close namespace my_namespace</span>
|
|
|
|
<span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span>
|
|
<span class="special">{</span>
|
|
<span class="comment">// Construct distribution with something we know will overflow.</span>
|
|
<span class="identifier">normal</span> <span class="identifier">norm</span><span class="special">(</span><span class="number">10</span><span class="special">,</span> <span class="number">2</span><span class="special">);</span> <span class="comment">// using 'anonymous-namespace'::normal</span>
|
|
<span class="identifier">errno</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span>
|
|
<span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"Result of quantile(norm, 0) is: "</span>
|
|
<span class="special"><<</span> <span class="identifier">quantile</span><span class="special">(</span><span class="identifier">norm</span><span class="special">,</span> <span class="number">0</span><span class="special">)</span> <span class="special"><<</span> <span class="identifier">endl</span><span class="special">;</span>
|
|
<span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"errno = "</span> <span class="special"><<</span> <span class="identifier">errno</span> <span class="special"><<</span> <span class="identifier">endl</span><span class="special">;</span>
|
|
<span class="identifier">errno</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span>
|
|
<span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"Result of quantile(norm, 1) is: "</span>
|
|
<span class="special"><<</span> <span class="identifier">quantile</span><span class="special">(</span><span class="identifier">norm</span><span class="special">,</span> <span class="number">1</span><span class="special">)</span> <span class="special"><<</span> <span class="identifier">endl</span><span class="special">;</span>
|
|
<span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"errno = "</span> <span class="special"><<</span> <span class="identifier">errno</span> <span class="special"><<</span> <span class="identifier">endl</span><span class="special">;</span>
|
|
<span class="comment">//</span>
|
|
<span class="comment">// Now try a discrete distribution:</span>
|
|
<span class="identifier">binomial</span> <span class="identifier">binom</span><span class="special">(</span><span class="number">20</span><span class="special">,</span> <span class="number">0.25</span><span class="special">);</span>
|
|
<span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"Result of quantile(binom, 0.05) is: "</span>
|
|
<span class="special"><<</span> <span class="identifier">quantile</span><span class="special">(</span><span class="identifier">binom</span><span class="special">,</span> <span class="number">0.05</span><span class="special">)</span> <span class="special"><<</span> <span class="identifier">endl</span><span class="special">;</span>
|
|
<span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"Result of quantile(complement(binom, 0.05)) is: "</span>
|
|
<span class="special"><<</span> <span class="identifier">quantile</span><span class="special">(</span><span class="identifier">complement</span><span class="special">(</span><span class="identifier">binom</span><span class="special">,</span> <span class="number">0.05</span><span class="special">))</span> <span class="special"><<</span> <span class="identifier">endl</span><span class="special">;</span>
|
|
<span class="special">}</span>
|
|
</pre>
|
|
</div>
|
|
<div class="copyright-footer">Copyright © 2006-2021 Nikhar Agrawal, Anton Bikineev, Matthew Borland,
|
|
Paul A. Bristow, Marco Guazzone, Christopher Kormanyos, Hubert Holin, Bruno
|
|
Lalande, John Maddock, Evan Miller, Jeremy Murphy, Matthew Pulver, Johan Råde,
|
|
Gautam Sewani, Benjamin Sobotta, Nicholas Thompson, Thijs van den Berg, Daryle
|
|
Walker and Xiaogang Zhang<p>
|
|
Distributed under the Boost Software License, Version 1.0. (See accompanying
|
|
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>)
|
|
</p>
|
|
</div>
|
|
<hr>
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