1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
|
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>Overview</title>
<link rel="stylesheet" href="../math.css" type="text/css">
<meta name="generator" content="DocBook XSL Stylesheets V1.77.1">
<link rel="home" href="../index.html" title="Math Toolkit 2.2.0">
<link rel="up" href="../cstdfloat.html" title="Chapter 3. Specified-width floating-point typedefs">
<link rel="prev" href="../cstdfloat.html" title="Chapter 3. Specified-width floating-point typedefs">
<link rel="next" href="rationale.html" title="Rationale">
</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="../cstdfloat.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../cstdfloat.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="rationale.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.overview"></a><a class="link" href="overview.html" title="Overview">Overview</a>
</h2></div></div></div>
<p>
The header <code class="computeroutput"><span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">cstdfloat</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span></code>
provides <span class="bold"><strong>optional</strong></span> standardized floating-point
<code class="computeroutput"><span class="keyword">typedef</span></code>s having <span class="bold"><strong>specified
widths</strong></span>. These are useful for writing portable code because they
should behave identically on all platforms. These <code class="computeroutput"><span class="keyword">typedef</span></code>s
are the floating-point analog of specified-width integers in <code class="computeroutput"><span class="special"><</span><span class="identifier">cstdint</span><span class="special">></span></code> and <code class="computeroutput"><span class="identifier">stdint</span><span class="special">.</span><span class="identifier">h</span></code>.
</p>
<p>
The <code class="computeroutput"><span class="keyword">typedef</span></code>s are based on <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3626.pdf" target="_top">N3626</a>
proposed for a new C++14 standard header <code class="computeroutput"><span class="special"><</span><span class="identifier">cstdfloat</span><span class="special">></span></code>
and <a href="http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1703.pdf" target="_top">N1703</a>
proposed for a new C language standard header <code class="computeroutput"><span class="special"><</span><span class="identifier">stdfloat</span><span class="special">.</span><span class="identifier">h</span><span class="special">></span></code>.
</p>
<p>
All <code class="computeroutput"><span class="keyword">typedef</span></code>s are in <code class="computeroutput"><span class="keyword">namespace</span> <span class="identifier">boost</span></code>
(would be in namespace <code class="computeroutput"><span class="identifier">std</span></code>
if eventually standardized).
</p>
<p>
The <code class="computeroutput"><span class="keyword">typedef</span></code>s include <code class="computeroutput"><span class="identifier">float16_t</span><span class="special">,</span> <span class="identifier">float32_t</span><span class="special">,</span> <span class="identifier">float64_t</span><span class="special">,</span> <span class="identifier">float80_t</span><span class="special">,</span> <span class="identifier">float128_t</span></code>, their corresponding least and
fast types, and the corresponding maximum-width type. The <code class="computeroutput"><span class="keyword">typedef</span></code>s
are based on underlying built-in types such as <code class="computeroutput"><span class="keyword">float</span></code>,
<code class="computeroutput"><span class="keyword">double</span></code>, or <code class="computeroutput"><span class="keyword">long</span>
<span class="keyword">double</span></code>, or based on other compiler-specific
non-standardized types such as <code class="computeroutput"><span class="identifier">__float128</span></code>.
The underlying types of these <code class="computeroutput"><span class="keyword">typedef</span></code>s
must conform with the corresponding specifications of binary16, binary32, binary64,
and binary128 in <a href="http://en.wikipedia.org/wiki/IEEE_floating_point" target="_top">IEEE_floating_point</a>
floating-point format.
</p>
<p>
The 128-bit floating-point type (of great interest in scientific and numeric
programming) is not required in the Boost header, and may not be supplied for
all platforms/compilers, because compiler support for a 128-bit floating-point
type is not mandated by either the C standard or the C++ standard.
</p>
<p>
See <a class="link" href="examples.html#math_toolkit.examples.je_lambda">Jahnke-Emden-Lambda function
example</a> for an example using both a CMath function and a Boost.Math
function to evaluate a moderately interesting function, the <a href="http://mathworld.wolfram.com/LambdaFunction.html" target="_top">Jahnke-Emden-Lambda
function</a> and <a class="link" href="examples.html#math_toolkit.examples.normal_table">normal
distribution</a> an example of a statistical distribution from Boost.Math
</p>
</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>
<div class="spirit-nav">
<a accesskey="p" href="../cstdfloat.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../cstdfloat.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="rationale.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a>
</div>
</body>
</html>
|
