You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
144 lines
6.5 KiB
HTML
144 lines
6.5 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
|
<html>
|
|
<!-- This manual is for GNU MPC, a library for multiple precision complex arithmetic,
|
|
version 1.0.3 of February 2015.
|
|
|
|
Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 INRIA
|
|
|
|
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 no
|
|
Invariant Sections. A copy of the license is included in the section
|
|
entitled "GNU Free Documentation License." -->
|
|
<!-- Created by GNU Texinfo 6.4, http://www.gnu.org/software/texinfo/ -->
|
|
<head>
|
|
<title>Initializing Complex Numbers (GNU MPC 1.0.3)</title>
|
|
|
|
<meta name="description" content="Initializing Complex Numbers (GNU MPC 1.0.3)">
|
|
<meta name="keywords" content="Initializing Complex Numbers (GNU MPC 1.0.3)">
|
|
<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="Concept-Index.html#Concept-Index" rel="index" title="Concept Index">
|
|
<link href="Complex-Functions.html#Complex-Functions" rel="up" title="Complex Functions">
|
|
<link href="Assigning-Complex-Numbers.html#Assigning-Complex-Numbers" rel="next" title="Assigning Complex Numbers">
|
|
<link href="Complex-Functions.html#Complex-Functions" rel="prev" title="Complex Functions">
|
|
<style type="text/css">
|
|
<!--
|
|
a.summary-letter {text-decoration: none}
|
|
blockquote.indentedblock {margin-right: 0em}
|
|
blockquote.smallindentedblock {margin-right: 0em; font-size: smaller}
|
|
blockquote.smallquotation {font-size: smaller}
|
|
div.display {margin-left: 3.2em}
|
|
div.example {margin-left: 3.2em}
|
|
div.lisp {margin-left: 3.2em}
|
|
div.smalldisplay {margin-left: 3.2em}
|
|
div.smallexample {margin-left: 3.2em}
|
|
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.nolinebreak {white-space: nowrap}
|
|
span.roman {font-family: initial; font-weight: normal}
|
|
span.sansserif {font-family: sans-serif; font-weight: normal}
|
|
ul.no-bullet {list-style: none}
|
|
-->
|
|
</style>
|
|
|
|
|
|
</head>
|
|
|
|
<body lang="en">
|
|
<a name="Initializing-Complex-Numbers"></a>
|
|
<div class="header">
|
|
<p>
|
|
Next: <a href="Assigning-Complex-Numbers.html#Assigning-Complex-Numbers" accesskey="n" rel="next">Assigning Complex Numbers</a>, Up: <a href="Complex-Functions.html#Complex-Functions" accesskey="u" rel="up">Complex Functions</a> [<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
|
|
</div>
|
|
<hr>
|
|
<a name="Initialization-Functions"></a>
|
|
<h3 class="section">5.1 Initialization Functions</h3>
|
|
|
|
<p>An <code>mpc_t</code> object must be initialized before storing the first value in
|
|
it. The functions <code>mpc_init2</code> and <code>mpc_init3</code>
|
|
are used for that purpose.
|
|
</p>
|
|
<dl>
|
|
<dt><a name="index-mpc_005finit2"></a>Function: <em>void</em> <strong>mpc_init2</strong> <em>(mpc_t <var>z</var>, mpfr_prec_t <var>prec</var>)</em></dt>
|
|
<dd><p>Initialize <var>z</var> to precision <var>prec</var> bits
|
|
and set its real and imaginary parts to NaN.
|
|
Normally, a variable should be initialized once only
|
|
or at least be cleared, using <code>mpc_clear</code>, between initializations.
|
|
</p></dd></dl>
|
|
|
|
<dl>
|
|
<dt><a name="index-mpc_005finit3"></a>Function: <em>void</em> <strong>mpc_init3</strong> <em>(mpc_t <var>z</var>, mpfr_prec_t <var>prec_r</var>, mpfr_prec_t <var>prec_i</var>)</em></dt>
|
|
<dd><p>Initialize <var>z</var> with the precision of its real part being
|
|
<var>prec_r</var> bits and the precision of its imaginary part being
|
|
<var>prec_i</var> bits, and set the real and imaginary parts to NaN.
|
|
</p></dd></dl>
|
|
|
|
<dl>
|
|
<dt><a name="index-mpc_005fclear"></a>Function: <em>void</em> <strong>mpc_clear</strong> <em>(mpc_t <var>z</var>)</em></dt>
|
|
<dd><p>Free the space occupied by <var>z</var>. Make sure to call this function for all
|
|
<code>mpc_t</code> variables when you are done with them.
|
|
</p></dd></dl>
|
|
|
|
<p>Here is an example on how to initialize complex variables:
|
|
</p><div class="example">
|
|
<pre class="example">{
|
|
mpc_t x, y;
|
|
mpc_init2 (x, 256); /* precision <em>exactly</em> 256 bits */
|
|
mpc_init3 (y, 100, 50); /* 100/50 bits for the real/imaginary part */
|
|
…
|
|
mpc_clear (x);
|
|
mpc_clear (y);
|
|
}
|
|
</pre></div>
|
|
|
|
<p>The following function is useful for changing the precision during a
|
|
calculation. A typical use would be for adjusting the precision gradually in
|
|
iterative algorithms like Newton-Raphson, making the computation precision
|
|
closely match the actual accurate part of the numbers.
|
|
</p>
|
|
<dl>
|
|
<dt><a name="index-mpc_005fset_005fprec"></a>Function: <em>void</em> <strong>mpc_set_prec</strong> <em>(mpc_t <var>x</var>, mpfr_prec_t <var>prec</var>)</em></dt>
|
|
<dd><p>Reset the precision of <var>x</var> to be <strong>exactly</strong> <var>prec</var> bits,
|
|
and set its real/imaginary parts to NaN.
|
|
The previous value stored in <var>x</var> is lost. It is equivalent to
|
|
a call to <code>mpc_clear(x)</code> followed by a call to
|
|
<code>mpc_init2(x, prec)</code>, but more efficient as no allocation is done in
|
|
case the current allocated space for the mantissa of <var>x</var> is sufficient.
|
|
</p></dd></dl>
|
|
|
|
<dl>
|
|
<dt><a name="index-mpc_005fget_005fprec"></a>Function: <em>mpfr_prec_t</em> <strong>mpc_get_prec</strong> <em>(mpc_t <var>x</var>)</em></dt>
|
|
<dd><p>If the real and imaginary part of <var>x</var> have the same precision, it is returned,
|
|
otherwise, 0 is returned.
|
|
</p></dd></dl>
|
|
|
|
<dl>
|
|
<dt><a name="index-mpc_005fget_005fprec2"></a>Function: <em>void</em> <strong>mpc_get_prec2</strong> <em>(mpfr_prec_t* <var>pr</var>, mpfr_prec_t* <var>pi</var>, mpc_t <var>x</var>)</em></dt>
|
|
<dd><p>Returns the precision of the real part of <var>x</var> via <var>pr</var> and of its imaginary part
|
|
via <var>pi</var>.
|
|
</p></dd></dl>
|
|
|
|
|
|
<hr>
|
|
<div class="header">
|
|
<p>
|
|
Next: <a href="Assigning-Complex-Numbers.html#Assigning-Complex-Numbers" accesskey="n" rel="next">Assigning Complex Numbers</a>, Up: <a href="Complex-Functions.html#Complex-Functions" accesskey="u" rel="up">Complex Functions</a> [<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
|
|
</div>
|
|
|
|
|
|
|
|
</body>
|
|
</html>
|