120 lines
6.9 KiB
HTML
120 lines
6.9 KiB
HTML
<html>
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
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<title>Policy Overview</title>
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<link rel="up" href="../policy.html" title="Chapter 20. Policies: Controlling Precision, Error Handling etc">
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<table cellpadding="2" width="100%"><tr>
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<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../boost.png"></td>
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<td align="center"><a href="../../../../../index.html">Home</a></td>
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<td align="center"><a href="../../../../../libs/libraries.htm">Libraries</a></td>
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<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td>
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<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td>
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<a accesskey="p" href="../policy.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../policy.html"><img src="../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="pol_tutorial.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a>
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<div class="section">
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<div class="titlepage"><div><div><h2 class="title" style="clear: both">
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<a name="math_toolkit.pol_overview"></a><a class="link" href="pol_overview.html" title="Policy Overview">Policy Overview</a>
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</h2></div></div></div>
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<p>
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Policies are a powerful fine-grain mechanism that allow you to customise the
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behaviour of this library according to your needs. There is more information
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available in the <a class="link" href="pol_tutorial.html" title="Policy Tutorial">policy tutorial</a>
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and the <a class="link" href="pol_ref.html" title="Policy Reference">policy reference</a>.
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</p>
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<p>
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Generally speaking, unless you find that the <a class="link" href="pol_tutorial/policy_tut_defaults.html" title="Policies Have Sensible Defaults">default
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policy behaviour</a> when encountering 'bad' argument values does not meet
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your needs, you should not need to worry about policies.
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</p>
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<p>
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Policies are a compile-time mechanism that allow you to change error-handling
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or calculation precision either program wide, or at the call site.
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</p>
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<p>
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Although the policy mechanism itself is rather complicated, in practice it
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is easy to use, and very flexible.
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</p>
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<p>
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Using policies you can control:
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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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<a class="link" href="pol_ref/error_handling_policies.html" title="Error Handling Policies">How results
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from 'bad' arguments are handled</a>, including those that cannot be
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fully evaluated.
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</li>
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<li class="listitem">
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How <a class="link" href="pol_ref/internal_promotion.html" title="Internal Floating-point Promotion Policies">accuracy is
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controlled by internal promotion</a> to use more precise types.
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</li>
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<li class="listitem">
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What working <a class="link" href="pol_ref/precision_pol.html" title="Precision Policies">precision</a>
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should be used to calculate results.
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</li>
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<li class="listitem">
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What to do when a <a class="link" href="pol_ref/assert_undefined.html" title="Mathematically Undefined Function Policies">mathematically
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undefined function</a> is used: Should this raise a run-time or compile-time
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error?
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</li>
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<li class="listitem">
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Whether <a class="link" href="pol_ref/discrete_quant_ref.html" title="Discrete Quantile Policies">discrete
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functions</a>, like the binomial, should return real or only integral
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values, and how they are rounded.
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</li>
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<li class="listitem">
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How many iterations a special function is permitted to perform in a series
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evaluation or root finding algorithm before it gives up and raises an
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<a class="link" href="error_handling.html#math_toolkit.error_handling.evaluation_error">evaluation_error</a>.
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</li>
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</ul></div>
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<p>
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You can control policies:
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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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Using <a class="link" href="pol_ref/policy_defaults.html" title="Using Macros to Change the Policy Defaults">macros</a>
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to change any default policy: the is the preferred method for installation
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wide policies.
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</li>
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<li class="listitem">
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At your chosen <a class="link" href="pol_ref/namespace_pol.html" title="Setting Polices at Namespace Scope">namespace
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scope</a> for distributions and/or functions: this is the preferred
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method for project, namespace, or translation unit scope policies.
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</li>
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<li class="listitem">
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In an ad-hoc manner <a class="link" href="pol_tutorial/ad_hoc_sf_policies.html" title="Changing the Policy on an Ad Hoc Basis for the Special Functions">by
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passing a specific policy to a special function</a>, or to a <a class="link" href="pol_tutorial/ad_hoc_dist_policies.html" title="Setting Policies for Distributions on an Ad Hoc Basis">statistical
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distribution</a>.
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</li>
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</ul></div>
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</div>
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<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
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<td align="left"></td>
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<td align="right"><div class="copyright-footer">Copyright © 2006-2019 Nikhar
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Agrawal, Anton Bikineev, Paul A. Bristow, Marco Guazzone, Christopher Kormanyos,
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Hubert Holin, Bruno Lalande, John Maddock, Jeremy Murphy, Matthew Pulver, Johan
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Råde, Gautam Sewani, Benjamin Sobotta, Nicholas Thompson, Thijs van den Berg,
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Daryle Walker and Xiaogang Zhang<p>
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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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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</p>
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</div></td>
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</tr></table>
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<hr>
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<div class="spirit-nav">
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<a accesskey="p" href="../policy.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../policy.html"><img src="../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="pol_tutorial.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a>
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