<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> <title>Policy Overview</title> <link rel="stylesheet" href="../math.css" type="text/css"> <meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> <link rel="home" href="../index.html" title="Math Toolkit 2.5.1"> <link rel="up" href="../policy.html" title="Chapter 15. Policies: Controlling Precision, Error Handling etc"> <link rel="prev" href="../policy.html" title="Chapter 15. Policies: Controlling Precision, Error Handling etc"> <link rel="next" href="pol_tutorial.html" title="Policy Tutorial"> </head> <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> <table cellpadding="2" width="100%"><tr> <td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../boost.png"></td> <td align="center"><a href="../../../../../index.html">Home</a></td> <td align="center"><a href="../../../../../libs/libraries.htm">Libraries</a></td> <td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> <td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> <td align="center"><a href="../../../../../more/index.htm">More</a></td> </tr></table> <hr> <div class="spirit-nav"> <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> </div> <div class="section"> <div class="titlepage"><div><div><h2 class="title" style="clear: both"> <a name="math_toolkit.pol_overview"></a><a class="link" href="pol_overview.html" title="Policy Overview">Policy Overview</a> </h2></div></div></div> <p> Policies are a powerful fine-grain mechanism that allow you to customise the behaviour of this library according to your needs. There is more information available in the <a class="link" href="pol_tutorial.html" title="Policy Tutorial">policy tutorial</a> and the <a class="link" href="pol_ref.html" title="Policy Reference">policy reference</a>. </p> <p> Generally speaking, unless you find that the <a class="link" href="pol_tutorial/policy_tut_defaults.html" title="Policies Have Sensible Defaults">default policy behaviour</a> when encountering 'bad' argument values does not meet your needs, you should not need to worry about policies. </p> <p> Policies are a compile-time mechanism that allow you to change error-handling or calculation precision either program wide, or at the call site. </p> <p> Although the policy mechanism itself is rather complicated, in practice it is easy to use, and very flexible. </p> <p> Using policies you can control: </p> <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> <li class="listitem"> <a class="link" href="pol_ref/error_handling_policies.html" title="Error Handling Policies">How results from 'bad' arguments are handled</a>, including those that cannot be fully evaluated. </li> <li class="listitem"> How <a class="link" href="pol_ref/internal_promotion.html" title="Internal Floating-point Promotion Policies">accuracy is controlled by internal promotion</a> to use more precise types. </li> <li class="listitem"> What working <a class="link" href="pol_ref/precision_pol.html" title="Precision Policies">precision</a> should be used to calculate results. </li> <li class="listitem"> What to do when a <a class="link" href="pol_ref/assert_undefined.html" title="Mathematically Undefined Function Policies">mathematically undefined function</a> is used: Should this raise a run-time or compile-time error? </li> <li class="listitem"> Whether <a class="link" href="pol_ref/discrete_quant_ref.html" title="Discrete Quantile Policies">discrete functions</a>, like the binomial, should return real or only integral values, and how they are rounded. </li> <li class="listitem"> How many iterations a special function is permitted to perform in a series evaluation or root finding algorithm before it gives up and raises an <a class="link" href="error_handling.html#math_toolkit.error_handling.evaluation_error">evaluation_error</a>. </li> </ul></div> <p> You can control policies: </p> <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> <li class="listitem"> Using <a class="link" href="pol_ref/policy_defaults.html" title="Using Macros to Change the Policy Defaults">macros</a> to change any default policy: the is the preferred method for installation wide policies. </li> <li class="listitem"> At your chosen <a class="link" href="pol_ref/namespace_pol.html" title="Setting Polices at Namespace Scope">namespace scope</a> for distributions and/or functions: this is the preferred method for project, namespace, or translation unit scope policies. </li> <li class="listitem"> 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 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 distribution</a>. </li> </ul></div> </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, Jeremy Murphy, 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> <div class="spirit-nav"> <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> </div> </body> </html>