<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
<html>
|
<!-- Copyright (C) 1999-2017 Free Software Foundation, Inc.
|
|
Permission is granted to copy, distribute and/or modify this document
|
under the terms of the GNU Free Documentation License, Version 1.3 or
|
any later version published by the Free Software Foundation; with the
|
Invariant Sections being "Funding Free Software", the Front-Cover
|
Texts being (a) (see below), and with the Back-Cover Texts being (b)
|
(see below). A copy of the license is included in the section entitled
|
"GNU Free Documentation License".
|
|
(a) The FSF's Front-Cover Text is:
|
|
A GNU Manual
|
|
(b) The FSF's Back-Cover Text is:
|
|
You have freedom to copy and modify this GNU Manual, like GNU
|
software. Copies published by the Free Software Foundation raise
|
funds for GNU development. -->
|
<!-- Created by GNU Texinfo 5.2, http://www.gnu.org/software/texinfo/ -->
|
<head>
|
<title>The GNU Fortran Compiler: RANDOM_NUMBER</title>
|
|
<meta name="description" content="The GNU Fortran Compiler: RANDOM_NUMBER">
|
<meta name="keywords" content="The GNU Fortran Compiler: RANDOM_NUMBER">
|
<meta name="resource-type" content="document">
|
<meta name="distribution" content="global">
|
<meta name="Generator" content="makeinfo">
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
|
<link href="index.html#Top" rel="start" title="Top">
|
<link href="Option-Index.html#Option-Index" rel="index" title="Option Index">
|
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
|
<link href="Intrinsic-Procedures.html#Intrinsic-Procedures" rel="up" title="Intrinsic Procedures">
|
<link href="RANDOM_005fSEED.html#RANDOM_005fSEED" rel="next" title="RANDOM_SEED">
|
<link href="RAND.html#RAND" rel="prev" title="RAND">
|
<style type="text/css">
|
<!--
|
a.summary-letter {text-decoration: none}
|
blockquote.smallquotation {font-size: smaller}
|
div.display {margin-left: 3.2em}
|
div.example {margin-left: 3.2em}
|
div.indentedblock {margin-left: 3.2em}
|
div.lisp {margin-left: 3.2em}
|
div.smalldisplay {margin-left: 3.2em}
|
div.smallexample {margin-left: 3.2em}
|
div.smallindentedblock {margin-left: 3.2em; font-size: smaller}
|
div.smalllisp {margin-left: 3.2em}
|
kbd {font-style:oblique}
|
pre.display {font-family: inherit}
|
pre.format {font-family: inherit}
|
pre.menu-comment {font-family: serif}
|
pre.menu-preformatted {font-family: serif}
|
pre.smalldisplay {font-family: inherit; font-size: smaller}
|
pre.smallexample {font-size: smaller}
|
pre.smallformat {font-family: inherit; font-size: smaller}
|
pre.smalllisp {font-size: smaller}
|
span.nocodebreak {white-space:nowrap}
|
span.nolinebreak {white-space:nowrap}
|
span.roman {font-family:serif; font-weight:normal}
|
span.sansserif {font-family:sans-serif; font-weight:normal}
|
ul.no-bullet {list-style: none}
|
-->
|
</style>
|
|
|
</head>
|
|
<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000">
|
<a name="RANDOM_005fNUMBER"></a>
|
<div class="header">
|
<p>
|
Next: <a href="RANDOM_005fSEED.html#RANDOM_005fSEED" accesskey="n" rel="next">RANDOM_SEED</a>, Previous: <a href="RAND.html#RAND" accesskey="p" rel="prev">RAND</a>, Up: <a href="Intrinsic-Procedures.html#Intrinsic-Procedures" accesskey="u" rel="up">Intrinsic Procedures</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p>
|
</div>
|
<hr>
|
<a name="RANDOM_005fNUMBER-_002d_002d_002d-Pseudo_002drandom-number"></a>
|
<h3 class="section">9.222 <code>RANDOM_NUMBER</code> — Pseudo-random number</h3>
|
<a name="index-RANDOM_005fNUMBER"></a>
|
<a name="index-random-number-generation-3"></a>
|
|
<dl compact="compact">
|
<dt><em>Description</em>:</dt>
|
<dd><p>Returns a single pseudorandom number or an array of pseudorandom numbers
|
from the uniform distribution over the range <em>0 \leq x < 1</em>.
|
</p>
|
<p>The runtime-library implements the xorshift1024* random number
|
generator (RNG). This generator has a period of <em>2^{1024} - 1</em>,
|
and when using multiple threads up to <em>2^{512}</em> threads can each
|
generate <em>2^{512}</em> random numbers before any aliasing occurs.
|
</p>
|
<p>Note that in a multi-threaded program (e.g. using OpenMP directives),
|
each thread will have its own random number state. For details of the
|
seeding procedure, see the documentation for the <code>RANDOM_SEED</code>
|
intrinsic.
|
</p>
|
|
</dd>
|
<dt><em>Standard</em>:</dt>
|
<dd><p>Fortran 95 and later
|
</p>
|
</dd>
|
<dt><em>Class</em>:</dt>
|
<dd><p>Subroutine
|
</p>
|
</dd>
|
<dt><em>Syntax</em>:</dt>
|
<dd><p><code>RANDOM_NUMBER(HARVEST)</code>
|
</p>
|
</dd>
|
<dt><em>Arguments</em>:</dt>
|
<dd><table>
|
<tr><td width="15%"><var>HARVEST</var></td><td width="70%">Shall be a scalar or an array of type <code>REAL</code>.</td></tr>
|
</table>
|
|
</dd>
|
<dt><em>Example</em>:</dt>
|
<dd><div class="smallexample">
|
<pre class="smallexample">program test_random_number
|
REAL :: r(5,5)
|
CALL RANDOM_NUMBER(r)
|
end program
|
</pre></div>
|
|
</dd>
|
<dt><em>See also</em>:</dt>
|
<dd><p><a href="RANDOM_005fSEED.html#RANDOM_005fSEED">RANDOM_SEED</a>
|
</p></dd>
|
</dl>
|
|
|
|
|
|
|
</body>
|
</html>
|
