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| <div class="section"> |
| <div class="titlepage"><div><div><h3 class="title"> |
| <a name="math_toolkit.pol_ref.error_handling_policies"></a><a class="link" href="error_handling_policies.html" title="Error Handling Policies">Error Handling |
| Policies</a> |
| </h3></div></div></div> |
| <p> |
| There are two orthogonal aspects to error handling: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> |
| <li class="listitem"> |
| What to do (if anything) with the error. |
| </li> |
| <li class="listitem"> |
| What kind of error is being raised. |
| </li> |
| </ul></div> |
| <h5> |
| <a name="math_toolkit.pol_ref.error_handling_policies.h0"></a> |
| <span class="phrase"><a name="math_toolkit.pol_ref.error_handling_policies.available_actions_when_an_error_"></a></span><a class="link" href="error_handling_policies.html#math_toolkit.pol_ref.error_handling_policies.available_actions_when_an_error_">Available |
| Actions When an Error is Raised</a> |
| </h5> |
| <p> |
| What to do with the error is encapsulated by an enumerated type: |
| </p> |
| <pre class="programlisting"><span class="keyword">namespace</span> <span class="identifier">boost</span> <span class="special">{</span> <span class="keyword">namespace</span> <span class="identifier">math</span> <span class="special">{</span> <span class="keyword">namespace</span> <span class="identifier">policies</span> <span class="special">{</span> |
| |
| <span class="keyword">enum</span> <span class="identifier">error_policy_type</span> |
| <span class="special">{</span> |
| <span class="identifier">throw_on_error</span> <span class="special">=</span> <span class="number">0</span><span class="special">,</span> <span class="comment">// throw an exception.</span> |
| <span class="identifier">errno_on_error</span> <span class="special">=</span> <span class="number">1</span><span class="special">,</span> <span class="comment">// set ::errno & return 0, NaN, infinity or best guess.</span> |
| <span class="identifier">ignore_error</span> <span class="special">=</span> <span class="number">2</span><span class="special">,</span> <span class="comment">// return 0, NaN, infinity or best guess.</span> |
| <span class="identifier">user_error</span> <span class="special">=</span> <span class="number">3</span> <span class="comment">// call a user-defined error handler.</span> |
| <span class="special">};</span> |
| |
| <span class="special">}}}</span> <span class="comment">// namespaces</span> |
| </pre> |
| <p> |
| The various enumerated values have the following meanings: |
| </p> |
| <h6> |
| <a name="math_toolkit.pol_ref.error_handling_policies.h1"></a> |
| <span class="phrase"><a name="math_toolkit.pol_ref.error_handling_policies.throw_on_error"></a></span><a class="link" href="error_handling_policies.html#math_toolkit.pol_ref.error_handling_policies.throw_on_error">throw_on_error</a> |
| </h6> |
| <p> |
| Will throw one of the following exceptions, depending upon the type of the |
| error: |
| </p> |
| <div class="informaltable"><table class="table"> |
| <colgroup> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th> |
| <p> |
| Error Type |
| </p> |
| </th> |
| <th> |
| <p> |
| Exception |
| </p> |
| </th> |
| </tr></thead> |
| <tbody> |
| <tr> |
| <td> |
| <p> |
| Domain Error |
| </p> |
| </td> |
| <td> |
| <p> |
| std::domain_error |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| Pole Error |
| </p> |
| </td> |
| <td> |
| <p> |
| std::domain_error |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| Overflow Error |
| </p> |
| </td> |
| <td> |
| <p> |
| std::overflow_error |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| Underflow Error |
| </p> |
| </td> |
| <td> |
| <p> |
| std::underflow_error |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| Denorm Error |
| </p> |
| </td> |
| <td> |
| <p> |
| std::underflow_error |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| Evaluation Error |
| </p> |
| </td> |
| <td> |
| <p> |
| boost::math::evaluation_error |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| Indeterminate Result Error |
| </p> |
| </td> |
| <td> |
| <p> |
| std::domain_error |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| <h6> |
| <a name="math_toolkit.pol_ref.error_handling_policies.h2"></a> |
| <span class="phrase"><a name="math_toolkit.pol_ref.error_handling_policies.errno_on_error"></a></span><a class="link" href="error_handling_policies.html#math_toolkit.pol_ref.error_handling_policies.errno_on_error">errno_on_error</a> |
| </h6> |
| <p> |
| Will set global <a href="http://en.wikipedia.org/wiki/Errno" target="_top"><code class="computeroutput"><span class="special">::</span><span class="identifier">errno</span></code></a> |
| <code class="computeroutput"><span class="special">::</span><span class="identifier">errno</span></code> |
| to one of the following values depending upon the error type (often EDOM |
| = 33 and ERANGE = 34), and then return the same value as if the error had |
| been ignored: |
| </p> |
| <div class="informaltable"><table class="table"> |
| <colgroup> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th> |
| <p> |
| Error Type |
| </p> |
| </th> |
| <th> |
| <p> |
| errno value |
| </p> |
| </th> |
| </tr></thead> |
| <tbody> |
| <tr> |
| <td> |
| <p> |
| Domain Error |
| </p> |
| </td> |
| <td> |
| <p> |
| EDOM |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| Pole Error |
| </p> |
| </td> |
| <td> |
| <p> |
| EDOM |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| Overflow Error |
| </p> |
| </td> |
| <td> |
| <p> |
| ERANGE |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| Underflow Error |
| </p> |
| </td> |
| <td> |
| <p> |
| ERANGE |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| Denorm Error |
| </p> |
| </td> |
| <td> |
| <p> |
| ERANGE |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| Evaluation Error |
| </p> |
| </td> |
| <td> |
| <p> |
| EDOM |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| Indeterminate Result Error |
| </p> |
| </td> |
| <td> |
| <p> |
| EDOM |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| <h6> |
| <a name="math_toolkit.pol_ref.error_handling_policies.h3"></a> |
| <span class="phrase"><a name="math_toolkit.pol_ref.error_handling_policies.ignore_error"></a></span><a class="link" href="error_handling_policies.html#math_toolkit.pol_ref.error_handling_policies.ignore_error">ignore_error</a> |
| </h6> |
| <p> |
| Will return one of the values below depending on the error type (<code class="computeroutput"><span class="special">::</span><span class="identifier">errno</span></code> |
| is NOT changed):: |
| </p> |
| <div class="informaltable"><table class="table"> |
| <colgroup> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th> |
| <p> |
| Error Type |
| </p> |
| </th> |
| <th> |
| <p> |
| Returned Value |
| </p> |
| </th> |
| </tr></thead> |
| <tbody> |
| <tr> |
| <td> |
| <p> |
| Domain Error |
| </p> |
| </td> |
| <td> |
| <p> |
| std::numeric_limits<T>::quiet_NaN() |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| Pole Error |
| </p> |
| </td> |
| <td> |
| <p> |
| std::numeric_limits<T>::quiet_NaN() |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| Overflow Error |
| </p> |
| </td> |
| <td> |
| <p> |
| std::numeric_limits<T>::infinity() |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| Underflow Error |
| </p> |
| </td> |
| <td> |
| <p> |
| 0 |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| Denorm Error |
| </p> |
| </td> |
| <td> |
| <p> |
| The denormalised value. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| Evaluation Error |
| </p> |
| </td> |
| <td> |
| <p> |
| The best guess (perhaps NaN) as to the result: which may be significantly |
| in error. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| Indeterminate Result Error |
| </p> |
| </td> |
| <td> |
| <p> |
| Depends on the function where the error occurred |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| <h6> |
| <a name="math_toolkit.pol_ref.error_handling_policies.h4"></a> |
| <span class="phrase"><a name="math_toolkit.pol_ref.error_handling_policies.user_error"></a></span><a class="link" href="error_handling_policies.html#math_toolkit.pol_ref.error_handling_policies.user_error">user_error</a> |
| </h6> |
| <p> |
| Will call a user defined error handler: these are forward declared in boost/math/policies/error_handling.hpp, |
| but the actual definitions must be provided by the user: |
| </p> |
| <pre class="programlisting"><span class="keyword">namespace</span> <span class="identifier">boost</span><span class="special">{</span> <span class="keyword">namespace</span> <span class="identifier">math</span><span class="special">{</span> <span class="keyword">namespace</span> <span class="identifier">policies</span><span class="special">{</span> |
| |
| <span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span> |
| <span class="identifier">T</span> <span class="identifier">user_domain_error</span><span class="special">(</span><span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">function</span><span class="special">,</span> <span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">message</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">T</span><span class="special">&</span> <span class="identifier">val</span><span class="special">);</span> |
| |
| <span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span> |
| <span class="identifier">T</span> <span class="identifier">user_pole_error</span><span class="special">(</span><span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">function</span><span class="special">,</span> <span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">message</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">T</span><span class="special">&</span> <span class="identifier">val</span><span class="special">);</span> |
| |
| <span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span> |
| <span class="identifier">T</span> <span class="identifier">user_overflow_error</span><span class="special">(</span><span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">function</span><span class="special">,</span> <span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">message</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">T</span><span class="special">&</span> <span class="identifier">val</span><span class="special">);</span> |
| |
| <span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span> |
| <span class="identifier">T</span> <span class="identifier">user_underflow_error</span><span class="special">(</span><span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">function</span><span class="special">,</span> <span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">message</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">T</span><span class="special">&</span> <span class="identifier">val</span><span class="special">);</span> |
| |
| <span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span> |
| <span class="identifier">T</span> <span class="identifier">user_denorm_error</span><span class="special">(</span><span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">function</span><span class="special">,</span> <span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">message</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">T</span><span class="special">&</span> <span class="identifier">val</span><span class="special">);</span> |
| |
| <span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span> |
| <span class="identifier">T</span> <span class="identifier">user_rounding_error</span><span class="special">(</span><span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">function</span><span class="special">,</span> <span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">message</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">T</span><span class="special">&</span> <span class="identifier">val</span><span class="special">);</span> |
| |
| <span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span> |
| <span class="identifier">T</span> <span class="identifier">user_evaluation_error</span><span class="special">(</span><span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">function</span><span class="special">,</span> <span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">message</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">T</span><span class="special">&</span> <span class="identifier">val</span><span class="special">);</span> |
| |
| <span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span> |
| <span class="identifier">T</span> <span class="identifier">user_indeterminate_result_error</span><span class="special">(</span><span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">function</span><span class="special">,</span> <span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">message</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">T</span><span class="special">&</span> <span class="identifier">val</span><span class="special">);</span> |
| |
| <span class="special">}}}</span> <span class="comment">// namespaces</span> |
| </pre> |
| <p> |
| Note that the strings <span class="emphasis"><em>function</em></span> and <span class="emphasis"><em>message</em></span> |
| may contain "%1%" format specifiers designed to be used in conjunction |
| with Boost.Format. If these strings are to be presented to the program's |
| end-user then the "%1%" format specifier should be replaced with |
| the name of type T in the <span class="emphasis"><em>function</em></span> string, and if there |
| is a %1% specifier in the <span class="emphasis"><em>message</em></span> string then it should |
| be replaced with the value of <span class="emphasis"><em>val</em></span>. |
| </p> |
| <p> |
| There is more information on user-defined error handlers in the <a class="link" href="../pol_tutorial/user_def_err_pol.html" title="Calling User Defined Error Handlers">tutorial |
| here</a>. |
| </p> |
| <h5> |
| <a name="math_toolkit.pol_ref.error_handling_policies.h5"></a> |
| <span class="phrase"><a name="math_toolkit.pol_ref.error_handling_policies.kinds_of_error_raised"></a></span><a class="link" href="error_handling_policies.html#math_toolkit.pol_ref.error_handling_policies.kinds_of_error_raised">Kinds |
| of Error Raised</a> |
| </h5> |
| <p> |
| There are six kinds of error reported by this library, which are summarised |
| in the following table: |
| </p> |
| <div class="informaltable"><table class="table"> |
| <colgroup> |
| <col> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th> |
| <p> |
| Error Type |
| </p> |
| </th> |
| <th> |
| <p> |
| Policy Class |
| </p> |
| </th> |
| <th> |
| <p> |
| Description |
| </p> |
| </th> |
| </tr></thead> |
| <tbody> |
| <tr> |
| <td> |
| <p> |
| Domain Error |
| </p> |
| </td> |
| <td> |
| <p> |
| boost::math::policies::domain_error<<span class="emphasis"><em>action</em></span>> |
| </p> |
| </td> |
| <td> |
| <p> |
| Raised when more or more arguments are outside the defined range |
| of the function. |
| </p> |
| <p> |
| Defaults to <code class="computeroutput"><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><span class="identifier">throw_on_error</span><span class="special">></span></code> |
| </p> |
| <p> |
| When the action is set to <span class="emphasis"><em>throw_on_error</em></span> then |
| throws <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">domain_error</span></code> |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| Pole Error |
| </p> |
| </td> |
| <td> |
| <p> |
| boost::math::policies::pole_error<<span class="emphasis"><em>action</em></span>> |
| </p> |
| </td> |
| <td> |
| <p> |
| Raised when more or more arguments would cause the function to |
| be evaluated at a pole. |
| </p> |
| <p> |
| Defaults to <code class="computeroutput"><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><span class="identifier">throw_on_error</span><span class="special">></span></code> |
| </p> |
| <p> |
| When the action is <span class="emphasis"><em>throw_on_error</em></span> then throw |
| a <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">domain_error</span></code> |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| Overflow Error |
| </p> |
| </td> |
| <td> |
| <p> |
| boost::math::policies::overflow_error<<span class="emphasis"><em>action</em></span>> |
| </p> |
| </td> |
| <td> |
| <p> |
| Raised when the result of the function is outside the representable |
| range of the floating point type used. |
| </p> |
| <p> |
| Defaults to <code class="computeroutput"><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><span class="identifier">throw_on_error</span><span class="special">></span></code>. |
| </p> |
| <p> |
| When the action is <span class="emphasis"><em>throw_on_error</em></span> then throws |
| a <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">overflow_error</span></code>. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| Underflow Error |
| </p> |
| </td> |
| <td> |
| <p> |
| boost::math::policies::underflow_error<<span class="emphasis"><em>action</em></span>> |
| </p> |
| </td> |
| <td> |
| <p> |
| Raised when the result of the function is too small to be represented |
| in the floating point type used. |
| </p> |
| <p> |
| Defaults to <code class="computeroutput"><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">underflow_error</span><span class="special"><</span><span class="identifier">ignore_error</span><span class="special">></span></code> |
| </p> |
| <p> |
| When the specified action is <span class="emphasis"><em>throw_on_error</em></span> |
| then throws a <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">underflow_error</span></code> |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| Denorm Error |
| </p> |
| </td> |
| <td> |
| <p> |
| boost::math::policies::denorm_error<<span class="emphasis"><em>action</em></span>> |
| </p> |
| </td> |
| <td> |
| <p> |
| Raised when the result of the function is a denormalised value. |
| </p> |
| <p> |
| Defaults to <code class="computeroutput"><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">denorm_error</span><span class="special"><</span><span class="identifier">ignore_error</span><span class="special">></span></code> |
| </p> |
| <p> |
| When the action is <span class="emphasis"><em>throw_on_error</em></span> then throws |
| a <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">underflow_error</span></code> |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| Rounding Error |
| </p> |
| </td> |
| <td> |
| <p> |
| boost::math::policies::rounding_error<<span class="emphasis"><em>action</em></span>> |
| </p> |
| </td> |
| <td> |
| <p> |
| Raised When one of the rounding functions <a class="link" href="../rounding/round.html" title="Rounding Functions">round</a>, |
| <a class="link" href="../rounding/trunc.html" title="Truncation Functions">trunc</a> or <a class="link" href="../rounding/modf.html" title="Integer and Fractional Part Splitting (modf)">modf</a> is called with |
| an argument that has no integer representation, or is too large |
| to be represented in the result type |
| </p> |
| <p> |
| Defaults to <code class="computeroutput"><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">rounding_error</span><span class="special"><</span><span class="identifier">throw_on_error</span><span class="special">></span></code> |
| </p> |
| <p> |
| When the action is <span class="emphasis"><em>throw_on_error</em></span> then throws |
| <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">math</span><span class="special">::</span><span class="identifier">rounding_error</span></code> |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| Evaluation Error |
| </p> |
| </td> |
| <td> |
| <p> |
| boost::math::policies::evaluation_error<<span class="emphasis"><em>action</em></span>> |
| </p> |
| </td> |
| <td> |
| <p> |
| Raised when the result of the function is well defined and finite, |
| but we were unable to compute it. Typically this occurs when an |
| iterative method fails to converge. Of course ideally this error |
| should never be raised: feel free to report it as a bug if it is! |
| </p> |
| <p> |
| Defaults to <code class="computeroutput"><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><span class="identifier">throw_on_error</span><span class="special">></span></code> |
| </p> |
| <p> |
| When the action is <span class="emphasis"><em>throw_on_error</em></span> then throws |
| <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">math</span><span class="special">::</span><span class="identifier">evaluation_error</span></code> |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| Indeterminate Result Error |
| </p> |
| </td> |
| <td> |
| <p> |
| boost::math::policies::indeterminate_result_error<<span class="emphasis"><em>action</em></span>> |
| </p> |
| </td> |
| <td> |
| <p> |
| Raised when the result of a function is not defined for the values |
| that were passed to it. |
| </p> |
| <p> |
| Defaults to <code class="computeroutput"><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">indeterminate_result_error</span><span class="special"><</span><span class="identifier">ignore_error</span><span class="special">></span></code> |
| </p> |
| <p> |
| When the action is <span class="emphasis"><em>throw_on_error</em></span> then throws |
| <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">domain_error</span></code> |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| <h5> |
| <a name="math_toolkit.pol_ref.error_handling_policies.h6"></a> |
| <span class="phrase"><a name="math_toolkit.pol_ref.error_handling_policies.examples"></a></span><a class="link" href="error_handling_policies.html#math_toolkit.pol_ref.error_handling_policies.examples">Examples</a> |
| </h5> |
| <p> |
| Suppose we want a call to <code class="computeroutput"><span class="identifier">tgamma</span></code> |
| to behave in a C-compatible way and set global <code class="computeroutput"><span class="special">::</span><span class="identifier">errno</span></code> rather than throw an exception, we |
| can achieve this at the call site using: |
| </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">special_functions</span><span class="special">/</span><span class="identifier">gamma</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| <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">tgamma</span><span class="special">;</span> |
| |
| <span class="comment">//using namespace boost::math::policies; may also be convenient.</span> |
| <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> |
| <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> |
| <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> |
| <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> |
| <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> |
| <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> |
| <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> |
| |
| <span class="comment">// Define a policy:</span> |
| <span class="keyword">typedef</span> <span class="identifier">policy</span><span class="special"><</span> |
| <span class="identifier">domain_error</span><span class="special"><</span><span class="identifier">errno_on_error</span><span class="special">>,</span> |
| <span class="identifier">pole_error</span><span class="special"><</span><span class="identifier">errno_on_error</span><span class="special">>,</span> |
| <span class="identifier">overflow_error</span><span class="special"><</span><span class="identifier">errno_on_error</span><span class="special">>,</span> |
| <span class="identifier">evaluation_error</span><span class="special"><</span><span class="identifier">errno_on_error</span><span class="special">></span> |
| <span class="special">></span> <span class="identifier">my_policy</span><span class="special">;</span> |
| |
| <span class="keyword">double</span> <span class="identifier">my_value</span> <span class="special">=</span> <span class="number">0.</span><span class="special">;</span> <span class="comment">// </span> |
| |
| <span class="comment">// Call the function applying my_policy:</span> |
| <span class="keyword">double</span> <span class="identifier">t1</span> <span class="special">=</span> <span class="identifier">tgamma</span><span class="special">(</span><span class="identifier">my_value</span><span class="special">,</span> <span class="identifier">my_policy</span><span class="special">());</span> |
| |
| <span class="comment">// Alternatively (and equivalently) we could use helpful function</span> |
| <span class="comment">// make_policy and define everything at the call site:</span> |
| <span class="keyword">double</span> <span class="identifier">t2</span> <span class="special">=</span> <span class="identifier">tgamma</span><span class="special">(</span><span class="identifier">my_value</span><span class="special">,</span> |
| <span class="identifier">make_policy</span><span class="special">(</span> |
| <span class="identifier">domain_error</span><span class="special"><</span><span class="identifier">errno_on_error</span><span class="special">>(),</span> |
| <span class="identifier">pole_error</span><span class="special"><</span><span class="identifier">errno_on_error</span><span class="special">>(),</span> |
| <span class="identifier">overflow_error</span><span class="special"><</span><span class="identifier">errno_on_error</span><span class="special">>(),</span> |
| <span class="identifier">evaluation_error</span><span class="special"><</span><span class="identifier">errno_on_error</span><span class="special">>()</span> <span class="special">)</span> |
| <span class="special">);</span> |
| </pre> |
| <p> |
| Suppose we want a statistical distribution to return infinities, rather than |
| throw exceptions, then we can use: |
| </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">normal</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| <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">normal_distribution</span><span class="special">;</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">// Define a specific policy:</span> |
| <span class="keyword">typedef</span> <span class="identifier">policy</span><span class="special"><</span> |
| <span class="identifier">overflow_error</span><span class="special"><</span><span class="identifier">ignore_error</span><span class="special">></span> |
| <span class="special">></span> <span class="identifier">my_policy</span><span class="special">;</span> |
| |
| <span class="comment">// Define the distribution, using my_policy:</span> |
| <span class="keyword">typedef</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">my_norm</span><span class="special">;</span> |
| |
| <span class="comment">// Construct a my_norm distribution, using default mean and standard deviation,</span> |
| <span class="comment">// and get a 0.05 or 5% quantile:</span> |
| <span class="keyword">double</span> <span class="identifier">q</span> <span class="special">=</span> <span class="identifier">quantile</span><span class="special">(</span><span class="identifier">my_norm</span><span class="special">(),</span> <span class="number">0.05</span><span class="special">);</span> <span class="comment">// = -1.64485</span> |
| </pre> |
| </div> |
| <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> |
| <td align="left"></td> |
| <td align="right"><div class="copyright-footer">Copyright © 2006-2010, 2012-2014 Nikhar Agrawal, |
| Anton Bikineev, Paul A. Bristow, Marco Guazzone, Christopher Kormanyos, Hubert |
| Holin, Bruno Lalande, John Maddock, Johan Råde, Gautam Sewani, Benjamin Sobotta, |
| 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></td> |
| </tr></table> |
| <hr> |
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