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| <div class="titlepage"><div><div><h3 class="title"> |
| <a name="math_toolkit.pol_ref.policy_defaults"></a><a class="link" href="policy_defaults.html" title="Using Macros to Change the Policy Defaults">Using Macros to |
| Change the Policy Defaults</a> |
| </h3></div></div></div> |
| <p> |
| You can use the various macros below to change any (or all) of the policies. |
| </p> |
| <p> |
| You can make a local change by placing a macro definition <span class="bold"><strong>before</strong></span> |
| a function or distribution #include. |
| </p> |
| <div class="caution"><table border="0" summary="Caution"> |
| <tr> |
| <td rowspan="2" align="center" valign="top" width="25"><img alt="[Caution]" src="../../../../../../doc/src/images/caution.png"></td> |
| <th align="left">Caution</th> |
| </tr> |
| <tr><td align="left" valign="top"><p> |
| There is a danger of One-Definition-Rule violations if you add ad-hoc macros |
| to more than one source files: these must be set the same in <span class="bold"><strong>every translation unit</strong></span>. |
| </p></td></tr> |
| </table></div> |
| <div class="caution"><table border="0" summary="Caution"> |
| <tr> |
| <td rowspan="2" align="center" valign="top" width="25"><img alt="[Caution]" src="../../../../../../doc/src/images/caution.png"></td> |
| <th align="left">Caution</th> |
| </tr> |
| <tr><td align="left" valign="top"><p> |
| If you place it after the #include it will have no effect, (and it will |
| affect only any other following #includes). This is probably not what you |
| intend! |
| </p></td></tr> |
| </table></div> |
| <p> |
| If you want to alter the defaults for any or all of the policies for <span class="bold"><strong>all</strong></span> functions and distributions, installation-wide, |
| then you can do so by defining various macros in <a href="../../../../../../boost/math/tools/user.hpp" target="_top">boost/math/tools/user.hpp</a>. |
| </p> |
| <h6> |
| <a name="math_toolkit.pol_ref.policy_defaults.h0"></a> |
| <span class="phrase"><a name="math_toolkit.pol_ref.policy_defaults.boost_math_domain_error_policy"></a></span><a class="link" href="policy_defaults.html#math_toolkit.pol_ref.policy_defaults.boost_math_domain_error_policy">BOOST_MATH_DOMAIN_ERROR_POLICY</a> |
| </h6> |
| <p> |
| Defines what happens when a domain error occurs, if not defined then defaults |
| to <code class="computeroutput"><span class="identifier">throw_on_error</span></code>, but can |
| be set to any of the enumerated actions for error handing: <code class="computeroutput"><span class="identifier">throw_on_error</span></code>, <code class="computeroutput"><span class="identifier">errno_on_error</span></code>, |
| <code class="computeroutput"><span class="identifier">ignore_error</span></code> or <code class="computeroutput"><span class="identifier">user_error</span></code>. |
| </p> |
| <h6> |
| <a name="math_toolkit.pol_ref.policy_defaults.h1"></a> |
| <span class="phrase"><a name="math_toolkit.pol_ref.policy_defaults.boost_math_pole_error_policy"></a></span><a class="link" href="policy_defaults.html#math_toolkit.pol_ref.policy_defaults.boost_math_pole_error_policy">BOOST_MATH_POLE_ERROR_POLICY</a> |
| </h6> |
| <p> |
| Defines what happens when a pole error occurs, if not defined then defaults |
| to <code class="computeroutput"><span class="identifier">throw_on_error</span></code>, but can |
| be set to any of the enumerated actions for error handing: <code class="computeroutput"><span class="identifier">throw_on_error</span></code>, <code class="computeroutput"><span class="identifier">errno_on_error</span></code>, |
| <code class="computeroutput"><span class="identifier">ignore_error</span></code> or <code class="computeroutput"><span class="identifier">user_error</span></code>. |
| </p> |
| <h6> |
| <a name="math_toolkit.pol_ref.policy_defaults.h2"></a> |
| <span class="phrase"><a name="math_toolkit.pol_ref.policy_defaults.boost_math_overflow_error_policy"></a></span><a class="link" href="policy_defaults.html#math_toolkit.pol_ref.policy_defaults.boost_math_overflow_error_policy">BOOST_MATH_OVERFLOW_ERROR_POLICY</a> |
| </h6> |
| <p> |
| Defines what happens when an overflow error occurs, if not defined then defaults |
| to <code class="computeroutput"><span class="identifier">throw_on_error</span></code>, but can |
| be set to any of the enumerated actions for error handing: <code class="computeroutput"><span class="identifier">throw_on_error</span></code>, <code class="computeroutput"><span class="identifier">errno_on_error</span></code>, |
| <code class="computeroutput"><span class="identifier">ignore_error</span></code> or <code class="computeroutput"><span class="identifier">user_error</span></code>. |
| </p> |
| <h6> |
| <a name="math_toolkit.pol_ref.policy_defaults.h3"></a> |
| <span class="phrase"><a name="math_toolkit.pol_ref.policy_defaults.boost_math_rounding_error_policy"></a></span><a class="link" href="policy_defaults.html#math_toolkit.pol_ref.policy_defaults.boost_math_rounding_error_policy">BOOST_MATH_ROUNDING_ERROR_POLICY</a> |
| </h6> |
| <p> |
| Defines what happens when a rounding error occurs, if not defined then defaults |
| to <code class="computeroutput"><span class="identifier">throw_on_error</span></code>, but can |
| be set to any of the enumerated actions for error handing: <code class="computeroutput"><span class="identifier">throw_on_error</span></code>, <code class="computeroutput"><span class="identifier">errno_on_error</span></code>, |
| <code class="computeroutput"><span class="identifier">ignore_error</span></code> or <code class="computeroutput"><span class="identifier">user_error</span></code>. |
| </p> |
| <h6> |
| <a name="math_toolkit.pol_ref.policy_defaults.h4"></a> |
| <span class="phrase"><a name="math_toolkit.pol_ref.policy_defaults.boost_math_evaluation_error_poli"></a></span><a class="link" href="policy_defaults.html#math_toolkit.pol_ref.policy_defaults.boost_math_evaluation_error_poli">BOOST_MATH_EVALUATION_ERROR_POLICY</a> |
| </h6> |
| <p> |
| Defines what happens when an internal evaluation error occurs, if not defined |
| then defaults to <code class="computeroutput"><span class="identifier">throw_on_error</span></code>, |
| but can be set to any of the enumerated actions for error handing: <code class="computeroutput"><span class="identifier">throw_on_error</span></code>, <code class="computeroutput"><span class="identifier">errno_on_error</span></code>, |
| <code class="computeroutput"><span class="identifier">ignore_error</span></code> or <code class="computeroutput"><span class="identifier">user_error</span></code>. |
| </p> |
| <h6> |
| <a name="math_toolkit.pol_ref.policy_defaults.h5"></a> |
| <span class="phrase"><a name="math_toolkit.pol_ref.policy_defaults.boost_math_underflow_error_polic"></a></span><a class="link" href="policy_defaults.html#math_toolkit.pol_ref.policy_defaults.boost_math_underflow_error_polic">BOOST_MATH_UNDERFLOW_ERROR_POLICY</a> |
| </h6> |
| <p> |
| Defines what happens when an overflow error occurs, if not defined then defaults |
| to <code class="computeroutput"><span class="identifier">ignore_error</span></code>, but can |
| be set to any of the enumerated actions for error handing: <code class="computeroutput"><span class="identifier">throw_on_error</span></code>, <code class="computeroutput"><span class="identifier">errno_on_error</span></code>, |
| <code class="computeroutput"><span class="identifier">ignore_error</span></code> or <code class="computeroutput"><span class="identifier">user_error</span></code>. |
| </p> |
| <h6> |
| <a name="math_toolkit.pol_ref.policy_defaults.h6"></a> |
| <span class="phrase"><a name="math_toolkit.pol_ref.policy_defaults.boost_math_denorm_error_policy"></a></span><a class="link" href="policy_defaults.html#math_toolkit.pol_ref.policy_defaults.boost_math_denorm_error_policy">BOOST_MATH_DENORM_ERROR_POLICY</a> |
| </h6> |
| <p> |
| Defines what happens when a denormalisation error occurs, if not defined |
| then defaults to <code class="computeroutput"><span class="identifier">ignore_error</span></code>, |
| but can be set to any of the enumerated actions for error handing: <code class="computeroutput"><span class="identifier">throw_on_error</span></code>, <code class="computeroutput"><span class="identifier">errno_on_error</span></code>, |
| <code class="computeroutput"><span class="identifier">ignore_error</span></code> or <code class="computeroutput"><span class="identifier">user_error</span></code>. |
| </p> |
| <h6> |
| <a name="math_toolkit.pol_ref.policy_defaults.h7"></a> |
| <span class="phrase"><a name="math_toolkit.pol_ref.policy_defaults.boost_math_indeterminate_result_"></a></span><a class="link" href="policy_defaults.html#math_toolkit.pol_ref.policy_defaults.boost_math_indeterminate_result_">BOOST_MATH_INDETERMINATE_RESULT_ERROR_POLICY</a> |
| </h6> |
| <p> |
| Defines what happens when the result is indeterminate, but where there is |
| none the less a convention for the result. If not defined then defaults to |
| <code class="computeroutput"><span class="identifier">ignore_error</span></code>, but can be |
| set to any of the enumerated actions for error handing: <code class="computeroutput"><span class="identifier">throw_on_error</span></code>, |
| <code class="computeroutput"><span class="identifier">errno_on_error</span></code>, <code class="computeroutput"><span class="identifier">ignore_error</span></code> or <code class="computeroutput"><span class="identifier">user_error</span></code>. |
| </p> |
| <h6> |
| <a name="math_toolkit.pol_ref.policy_defaults.h8"></a> |
| <span class="phrase"><a name="math_toolkit.pol_ref.policy_defaults.boost_math_digits10_policy"></a></span><a class="link" href="policy_defaults.html#math_toolkit.pol_ref.policy_defaults.boost_math_digits10_policy">BOOST_MATH_DIGITS10_POLICY</a> |
| </h6> |
| <p> |
| Defines how many decimal digits to use in internal computations: defaults |
| to <code class="computeroutput"><span class="number">0</span></code> - meaning use all available |
| digits - but can be set to some other decimal value. Since setting this is |
| likely to have a substantial impact on accuracy, it's not generally recommended |
| that you change this from the default. |
| </p> |
| <h6> |
| <a name="math_toolkit.pol_ref.policy_defaults.h9"></a> |
| <span class="phrase"><a name="math_toolkit.pol_ref.policy_defaults.boost_math_promote_float_policy"></a></span><a class="link" href="policy_defaults.html#math_toolkit.pol_ref.policy_defaults.boost_math_promote_float_policy">BOOST_MATH_PROMOTE_FLOAT_POLICY</a> |
| </h6> |
| <p> |
| Determines whether <code class="computeroutput"><span class="keyword">float</span></code> types |
| get promoted to <code class="computeroutput"><span class="keyword">double</span></code> internally |
| to ensure maximum precision in the result, defaults to <code class="computeroutput"><span class="keyword">true</span></code>, |
| but can be set to <code class="computeroutput"><span class="keyword">false</span></code> to turn |
| promotion of <code class="computeroutput"><span class="keyword">float</span></code>'s off. |
| </p> |
| <h6> |
| <a name="math_toolkit.pol_ref.policy_defaults.h10"></a> |
| <span class="phrase"><a name="math_toolkit.pol_ref.policy_defaults.boost_math_promote_double_policy"></a></span><a class="link" href="policy_defaults.html#math_toolkit.pol_ref.policy_defaults.boost_math_promote_double_policy">BOOST_MATH_PROMOTE_DOUBLE_POLICY</a> |
| </h6> |
| <p> |
| Determines whether <code class="computeroutput"><span class="keyword">double</span></code> types |
| get promoted to <code class="computeroutput"><span class="keyword">long</span> <span class="keyword">double</span></code> |
| internally to ensure maximum precision in the result, defaults to <code class="computeroutput"><span class="keyword">true</span></code>, but can be set to <code class="computeroutput"><span class="keyword">false</span></code> |
| to turn promotion of <code class="computeroutput"><span class="keyword">double</span></code>'s |
| off. |
| </p> |
| <h6> |
| <a name="math_toolkit.pol_ref.policy_defaults.h11"></a> |
| <span class="phrase"><a name="math_toolkit.pol_ref.policy_defaults.boost_math_discrete_quantile_pol"></a></span><a class="link" href="policy_defaults.html#math_toolkit.pol_ref.policy_defaults.boost_math_discrete_quantile_pol">BOOST_MATH_DISCRETE_QUANTILE_POLICY</a> |
| </h6> |
| <p> |
| Determines how discrete quantiles return their results: either as an integer, |
| or as a real value, can be set to one of the enumerated values: <code class="computeroutput"><span class="identifier">real</span></code>, <code class="computeroutput"><span class="identifier">integer_round_outwards</span></code>, |
| <code class="computeroutput"><span class="identifier">integer_round_inwards</span></code>, <code class="computeroutput"><span class="identifier">integer_round_down</span></code>, <code class="computeroutput"><span class="identifier">integer_round_up</span></code>, |
| <code class="computeroutput"><span class="identifier">integer_round_nearest</span></code>. Defaults |
| to <code class="computeroutput"><span class="identifier">integer_round_outwards</span></code>. |
| </p> |
| <h6> |
| <a name="math_toolkit.pol_ref.policy_defaults.h12"></a> |
| <span class="phrase"><a name="math_toolkit.pol_ref.policy_defaults.boost_math_assert_undefined_poli"></a></span><a class="link" href="policy_defaults.html#math_toolkit.pol_ref.policy_defaults.boost_math_assert_undefined_poli">BOOST_MATH_ASSERT_UNDEFINED_POLICY</a> |
| </h6> |
| <p> |
| Determines whether functions that are mathematically undefined for a specific |
| distribution compile or raise a static (i.e. compile-time) assertion. Defaults |
| to <code class="computeroutput"><span class="keyword">true</span></code>: meaning that any mathematically |
| undefined function will not compile. When set to <code class="computeroutput"><span class="keyword">false</span></code> |
| then the function will compile but return the result of a domain error: this |
| can be useful for some generic code, that needs to work with all distributions |
| and determine at runtime whether or not a particular property is well defined. |
| </p> |
| <h6> |
| <a name="math_toolkit.pol_ref.policy_defaults.h13"></a> |
| <span class="phrase"><a name="math_toolkit.pol_ref.policy_defaults.boost_math_max_series_iteration_"></a></span><a class="link" href="policy_defaults.html#math_toolkit.pol_ref.policy_defaults.boost_math_max_series_iteration_">BOOST_MATH_MAX_SERIES_ITERATION_POLICY</a> |
| </h6> |
| <p> |
| Determines how many series iterations a special function is permitted to |
| perform before it gives up and returns an <a class="link" href="../error_handling.html#math_toolkit.error_handling.evaluation_error">evaluation_error</a>: |
| Defaults to 1000000. |
| </p> |
| <h6> |
| <a name="math_toolkit.pol_ref.policy_defaults.h14"></a> |
| <span class="phrase"><a name="math_toolkit.pol_ref.policy_defaults.boost_math_max_root_iteration_po"></a></span><a class="link" href="policy_defaults.html#math_toolkit.pol_ref.policy_defaults.boost_math_max_root_iteration_po">BOOST_MATH_MAX_ROOT_ITERATION_POLICY</a> |
| </h6> |
| <p> |
| Determines how many root-finding iterations a special function is permitted |
| to perform before it gives up and returns an <a class="link" href="../error_handling.html#math_toolkit.error_handling.evaluation_error">evaluation_error</a>: |
| Defaults to 200. |
| </p> |
| <h6> |
| <a name="math_toolkit.pol_ref.policy_defaults.h15"></a> |
| <span class="phrase"><a name="math_toolkit.pol_ref.policy_defaults.example"></a></span><a class="link" href="policy_defaults.html#math_toolkit.pol_ref.policy_defaults.example">Example</a> |
| </h6> |
| <p> |
| Suppose we want overflow errors to set <code class="computeroutput"><span class="special">::</span><span class="identifier">errno</span></code> and return an infinity, discrete |
| quantiles to return a real-valued result (rather than round to integer), |
| and for mathematically undefined functions to compile, but return a domain |
| error. Then we could add the following to boost/math/tools/user.hpp: |
| </p> |
| <pre class="programlisting"><span class="preprocessor">#define</span> <span class="identifier">BOOST_MATH_OVERFLOW_ERROR_POLICY</span> <span class="identifier">errno_on_error</span> |
| <span class="preprocessor">#define</span> <span class="identifier">BOOST_MATH_DISCRETE_QUANTILE_POLICY</span> <span class="identifier">real</span> |
| <span class="preprocessor">#define</span> <span class="identifier">BOOST_MATH_ASSERT_UNDEFINED_POLICY</span> <span class="keyword">false</span> |
| </pre> |
| <p> |
| or we could place these definitions <span class="bold"><strong>before</strong></span> |
| </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> |
| </pre> |
| <p> |
| in a source .cpp file. |
| </p> |
| </div> |
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| <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>) |
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