Spaces:
Sleeping
Sleeping
| <html lang="en" data-content_root="../"> | |
| <head> | |
| <meta charset="utf-8" /> | |
| <meta name="viewport" content="width=device-width, initial-scale=1.0" /><meta name="viewport" content="width=device-width, initial-scale=1" /> | |
| <meta property="og:title" content="cmath — Mathematical functions for complex numbers" /> | |
| <meta property="og:type" content="website" /> | |
| <meta property="og:url" content="https://docs.python.org/3/library/cmath.html" /> | |
| <meta property="og:site_name" content="Python documentation" /> | |
| <meta property="og:description" content="This module provides access to mathematical functions for complex numbers. The functions in this module accept integers, floating-point numbers or complex numbers as arguments. They will also accep..." /> | |
| <meta property="og:image:width" content="1146" /> | |
| <meta property="og:image:height" content="600" /> | |
| <meta property="og:image" content="https://docs.python.org/3.15/_images/social_previews/summary_library_cmath_a01a6ef5.png" /> | |
| <meta property="og:image:alt" content="This module provides access to mathematical functions for complex numbers. The functions in this module accept integers, floating-point numbers or complex numbers as arguments. They will also accep..." /> | |
| <meta name="description" content="This module provides access to mathematical functions for complex numbers. The functions in this module accept integers, floating-point numbers or complex numbers as arguments. They will also accep..." /> | |
| <meta name="twitter:card" content="summary_large_image" /> | |
| <meta name="theme-color" content="#3776ab"> | |
| <title>cmath — Mathematical functions for complex numbers — Python 3.15.0a6 documentation</title><meta name="viewport" content="width=device-width, initial-scale=1.0"> | |
| <link rel="stylesheet" type="text/css" href="../_static/pygments.css?v=b86133f3" /> | |
| <link rel="stylesheet" type="text/css" href="../_static/classic.css?v=234b1a7c" /> | |
| <link rel="stylesheet" type="text/css" href="../_static/pydoctheme.css?v=89a2f22a" /> | |
| <link rel="stylesheet" type="text/css" href="../_static/profiling-sampling-visualization.css?v=0c2600ae" /> | |
| <link id="pygments_dark_css" media="(prefers-color-scheme: dark)" rel="stylesheet" type="text/css" href="../_static/pygments_dark.css?v=5349f25f" /> | |
| <script src="../_static/documentation_options.js?v=6b7c9ff5"></script> | |
| <script src="../_static/doctools.js?v=9bcbadda"></script> | |
| <script src="../_static/sphinx_highlight.js?v=dc90522c"></script> | |
| <script src="../_static/profiling-sampling-visualization.js?v=9811ed04"></script> | |
| <script src="../_static/sidebar.js"></script> | |
| <link rel="search" type="application/opensearchdescription+xml" | |
| title="Search within Python 3.15.0a6 documentation" | |
| href="../_static/opensearch.xml"/> | |
| <link rel="author" title="About these documents" href="../about.html" /> | |
| <link rel="index" title="Index" href="../genindex.html" /> | |
| <link rel="search" title="Search" href="../search.html" /> | |
| <link rel="copyright" title="Copyright" href="../copyright.html" /> | |
| <link rel="next" title="decimal — Decimal fixed-point and floating-point arithmetic" href="decimal.html" /> | |
| <link rel="prev" title="math.integer — integer-specific mathematics functions" href="math.integer.html" /> | |
| <script defer file-types="bz2,epub,zip" data-domain="docs.python.org" src="https://analytics.python.org/js/script.file-downloads.outbound-links.js"></script> | |
| <link rel="canonical" href="https://docs.python.org/3/library/cmath.html"> | |
| <style> | |
| @media only screen { | |
| table.full-width-table { | |
| width: 100%; | |
| } | |
| } | |
| </style> | |
| <link rel="stylesheet" href="../_static/pydoctheme_dark.css" media="(prefers-color-scheme: dark)" id="pydoctheme_dark_css"> | |
| <link rel="shortcut icon" type="image/png" href="../_static/py.svg"> | |
| <script type="text/javascript" src="../_static/copybutton.js"></script> | |
| <script type="text/javascript" src="../_static/menu.js"></script> | |
| <script type="text/javascript" src="../_static/search-focus.js"></script> | |
| <script type="text/javascript" src="../_static/themetoggle.js"></script> | |
| <script type="text/javascript" src="../_static/rtd_switcher.js"></script> | |
| <meta name="readthedocs-addons-api-version" content="1"> | |
| </head> | |
| <body> | |
| <div class="mobile-nav"> | |
| <input type="checkbox" id="menuToggler" class="toggler__input" aria-controls="navigation" | |
| aria-pressed="false" aria-expanded="false" role="button" aria-label="Menu"> | |
| <nav class="nav-content" role="navigation"> | |
| <label for="menuToggler" class="toggler__label"> | |
| <span></span> | |
| </label> | |
| <span class="nav-items-wrapper"> | |
| <a href="https://www.python.org/" class="nav-logo"> | |
| <img src="../_static/py.svg" alt="Python logo"> | |
| </a> | |
| <span class="version_switcher_placeholder"></span> | |
| <form role="search" class="search" action="../search.html" method="get"> | |
| <svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" class="search-icon"> | |
| <path fill-rule="nonzero" fill="currentColor" d="M15.5 14h-.79l-.28-.27a6.5 6.5 0 001.48-5.34c-.47-2.78-2.79-5-5.59-5.34a6.505 6.505 0 00-7.27 7.27c.34 2.8 2.56 5.12 5.34 5.59a6.5 6.5 0 005.34-1.48l.27.28v.79l4.25 4.25c.41.41 1.08.41 1.49 0 .41-.41.41-1.08 0-1.49L15.5 14zm-6 0C7.01 14 5 11.99 5 9.5S7.01 5 9.5 5 14 7.01 14 9.5 11.99 14 9.5 14z"></path> | |
| </svg> | |
| <input placeholder="Quick search" aria-label="Quick search" type="search" name="q"> | |
| <input type="submit" value="Go"> | |
| </form> | |
| </span> | |
| </nav> | |
| <div class="menu-wrapper"> | |
| <nav class="menu" role="navigation" aria-label="main navigation"> | |
| <div class="language_switcher_placeholder"></div> | |
| <label class="theme-selector-label"> | |
| Theme | |
| <select class="theme-selector" oninput="activateTheme(this.value)"> | |
| <option value="auto" selected>Auto</option> | |
| <option value="light">Light</option> | |
| <option value="dark">Dark</option> | |
| </select> | |
| </label> | |
| <div> | |
| <h3><a href="../contents.html">Table of Contents</a></h3> | |
| <ul> | |
| <li><a class="reference internal" href="#"><code class="xref py py-mod docutils literal notranslate"><span class="pre">cmath</span></code> — Mathematical functions for complex numbers</a><ul> | |
| <li><a class="reference internal" href="#conversions-to-and-from-polar-coordinates">Conversions to and from polar coordinates</a></li> | |
| <li><a class="reference internal" href="#power-and-logarithmic-functions">Power and logarithmic functions</a></li> | |
| <li><a class="reference internal" href="#trigonometric-functions">Trigonometric functions</a></li> | |
| <li><a class="reference internal" href="#hyperbolic-functions">Hyperbolic functions</a></li> | |
| <li><a class="reference internal" href="#classification-functions">Classification functions</a></li> | |
| <li><a class="reference internal" href="#constants">Constants</a></li> | |
| </ul> | |
| </li> | |
| </ul> | |
| </div> | |
| <div> | |
| <h4>Previous topic</h4> | |
| <p class="topless"><a href="math.integer.html" | |
| title="previous chapter"><code class="xref py py-mod docutils literal notranslate"><span class="pre">math.integer</span></code> — integer-specific mathematics functions</a></p> | |
| </div> | |
| <div> | |
| <h4>Next topic</h4> | |
| <p class="topless"><a href="decimal.html" | |
| title="next chapter"><code class="xref py py-mod docutils literal notranslate"><span class="pre">decimal</span></code> — Decimal fixed-point and floating-point arithmetic</a></p> | |
| </div> | |
| <script> | |
| document.addEventListener('DOMContentLoaded', () => { | |
| const title = document.querySelector('meta[property="og:title"]').content; | |
| const elements = document.querySelectorAll('.improvepage'); | |
| const pageurl = window.location.href.split('?')[0]; | |
| elements.forEach(element => { | |
| const url = new URL(element.href.split('?')[0].replace("-nojs", "")); | |
| url.searchParams.set('pagetitle', title); | |
| url.searchParams.set('pageurl', pageurl); | |
| url.searchParams.set('pagesource', "library/cmath.rst"); | |
| element.href = url.toString(); | |
| }); | |
| }); | |
| </script> | |
| <div role="note" aria-label="source link"> | |
| <h3>This page</h3> | |
| <ul class="this-page-menu"> | |
| <li><a href="../bugs.html">Report a bug</a></li> | |
| <li><a class="improvepage" href="../improve-page-nojs.html">Improve this page</a></li> | |
| <li> | |
| <a href="https://github.com/python/cpython/blob/main/Doc/library/cmath.rst?plain=1" | |
| rel="nofollow">Show source | |
| </a> | |
| </li> | |
| </ul> | |
| </div> | |
| </nav> | |
| </div> | |
| </div> | |
| <div class="related" role="navigation" aria-label="Related"> | |
| <h3>Navigation</h3> | |
| <ul> | |
| <li class="right" style="margin-right: 10px"> | |
| <a href="../genindex.html" title="General Index" | |
| accesskey="I">index</a></li> | |
| <li class="right" > | |
| <a href="../py-modindex.html" title="Python Module Index" | |
| >modules</a> |</li> | |
| <li class="right" > | |
| <a href="decimal.html" title="decimal — Decimal fixed-point and floating-point arithmetic" | |
| accesskey="N">next</a> |</li> | |
| <li class="right" > | |
| <a href="math.integer.html" title="math.integer — integer-specific mathematics functions" | |
| accesskey="P">previous</a> |</li> | |
| <li><img src="../_static/py.svg" alt="Python logo" style="vertical-align: middle; margin-top: -1px"></li> | |
| <li><a href="https://www.python.org/">Python</a> »</li> | |
| <li class="switchers"> | |
| <div class="language_switcher_placeholder"></div> | |
| <div class="version_switcher_placeholder"></div> | |
| </li> | |
| <li> | |
| </li> | |
| <li id="cpython-language-and-version"> | |
| <a href="../index.html">3.15.0a6 Documentation</a> » | |
| </li> | |
| <li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> »</li> | |
| <li class="nav-item nav-item-2"><a href="numeric.html" accesskey="U">Numeric and Mathematical Modules</a> »</li> | |
| <li class="nav-item nav-item-this"><a href=""><code class="xref py py-mod docutils literal notranslate"><span class="pre">cmath</span></code> — Mathematical functions for complex numbers</a></li> | |
| <li class="right"> | |
| <div class="inline-search" role="search"> | |
| <form class="inline-search" action="../search.html" method="get"> | |
| <input placeholder="Quick search" aria-label="Quick search" type="search" name="q" id="search-box"> | |
| <input type="submit" value="Go"> | |
| </form> | |
| </div> | |
| | | |
| </li> | |
| <li class="right"> | |
| <label class="theme-selector-label"> | |
| Theme | |
| <select class="theme-selector" oninput="activateTheme(this.value)"> | |
| <option value="auto" selected>Auto</option> | |
| <option value="light">Light</option> | |
| <option value="dark">Dark</option> | |
| </select> | |
| </label> |</li> | |
| </ul> | |
| </div> | |
| <div class="document"> | |
| <div class="documentwrapper"> | |
| <div class="bodywrapper"> | |
| <div class="body" role="main"> | |
| <section id="module-cmath"> | |
| <span id="cmath-mathematical-functions-for-complex-numbers"></span><h1><code class="xref py py-mod docutils literal notranslate"><span class="pre">cmath</span></code> — Mathematical functions for complex numbers<a class="headerlink" href="#module-cmath" title="Link to this heading">¶</a></h1> | |
| <hr class="docutils" /> | |
| <p>This module provides access to mathematical functions for complex numbers. The | |
| functions in this module accept integers, floating-point numbers or complex | |
| numbers as arguments. They will also accept any Python object that has either a | |
| <a class="reference internal" href="../reference/datamodel.html#object.__complex__" title="object.__complex__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__complex__()</span></code></a> or a <a class="reference internal" href="../reference/datamodel.html#object.__float__" title="object.__float__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__float__()</span></code></a> method: these methods are used to | |
| convert the object to a complex or floating-point number, respectively, and | |
| the function is then applied to the result of the conversion.</p> | |
| <div class="admonition note"> | |
| <p class="admonition-title">Note</p> | |
| <p>For functions involving branch cuts, we have the problem of deciding how to | |
| define those functions on the cut itself. Following Kahan’s “Branch cuts for | |
| complex elementary functions” paper, as well as Annex G of C99 and later C | |
| standards, we use the sign of zero to distinguish one side of the branch cut | |
| from the other: for a branch cut along (a portion of) the real axis we look | |
| at the sign of the imaginary part, while for a branch cut along the | |
| imaginary axis we look at the sign of the real part.</p> | |
| <p>For example, the <a class="reference internal" href="#cmath.sqrt" title="cmath.sqrt"><code class="xref py py-func docutils literal notranslate"><span class="pre">cmath.sqrt()</span></code></a> function has a branch cut along the | |
| negative real axis. An argument of <code class="docutils literal notranslate"><span class="pre">-2-0j</span></code> is treated as | |
| though it lies <em>below</em> the branch cut, and so gives a result on the negative | |
| imaginary axis:</p> | |
| <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">cmath</span><span class="o">.</span><span class="n">sqrt</span><span class="p">(</span><span class="o">-</span><span class="mi">2</span><span class="o">-</span><span class="mi">0</span><span class="n">j</span><span class="p">)</span> | |
| <span class="go">-1.4142135623730951j</span> | |
| </pre></div> | |
| </div> | |
| <p>But an argument of <code class="docutils literal notranslate"><span class="pre">-2+0j</span></code> is treated as though it lies above | |
| the branch cut:</p> | |
| <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">cmath</span><span class="o">.</span><span class="n">sqrt</span><span class="p">(</span><span class="o">-</span><span class="mi">2</span><span class="o">+</span><span class="mi">0</span><span class="n">j</span><span class="p">)</span> | |
| <span class="go">1.4142135623730951j</span> | |
| </pre></div> | |
| </div> | |
| </div> | |
| <table class="docutils align-default"> | |
| <tbody> | |
| <tr class="row-odd"><td colspan="2"><p><strong>Conversions to and from polar coordinates</strong></p></td> | |
| </tr> | |
| <tr class="row-even"><td><p><a class="reference internal" href="#cmath.phase" title="cmath.phase"><code class="xref py py-func docutils literal notranslate"><span class="pre">phase(z)</span></code></a></p></td> | |
| <td><p>Return the phase of <em>z</em></p></td> | |
| </tr> | |
| <tr class="row-odd"><td><p><a class="reference internal" href="#cmath.polar" title="cmath.polar"><code class="xref py py-func docutils literal notranslate"><span class="pre">polar(z)</span></code></a></p></td> | |
| <td><p>Return the representation of <em>z</em> in polar coordinates</p></td> | |
| </tr> | |
| <tr class="row-even"><td><p><a class="reference internal" href="#cmath.rect" title="cmath.rect"><code class="xref py py-func docutils literal notranslate"><span class="pre">rect(r,</span> <span class="pre">phi)</span></code></a></p></td> | |
| <td><p>Return the complex number <em>z</em> with polar coordinates <em>r</em> and <em>phi</em></p></td> | |
| </tr> | |
| <tr class="row-odd"><td colspan="2"><p><strong>Power and logarithmic functions</strong></p></td> | |
| </tr> | |
| <tr class="row-even"><td><p><a class="reference internal" href="#cmath.exp" title="cmath.exp"><code class="xref py py-func docutils literal notranslate"><span class="pre">exp(z)</span></code></a></p></td> | |
| <td><p>Return <em>e</em> raised to the power <em>z</em></p></td> | |
| </tr> | |
| <tr class="row-odd"><td><p><a class="reference internal" href="#cmath.log" title="cmath.log"><code class="xref py py-func docutils literal notranslate"><span class="pre">log(z[,</span> <span class="pre">base])</span></code></a></p></td> | |
| <td><p>Return the logarithm of <em>z</em> to the given <em>base</em> (<em>e</em> by default)</p></td> | |
| </tr> | |
| <tr class="row-even"><td><p><a class="reference internal" href="#cmath.log10" title="cmath.log10"><code class="xref py py-func docutils literal notranslate"><span class="pre">log10(z)</span></code></a></p></td> | |
| <td><p>Return the base-10 logarithm of <em>z</em></p></td> | |
| </tr> | |
| <tr class="row-odd"><td><p><a class="reference internal" href="#cmath.sqrt" title="cmath.sqrt"><code class="xref py py-func docutils literal notranslate"><span class="pre">sqrt(z)</span></code></a></p></td> | |
| <td><p>Return the square root of <em>z</em></p></td> | |
| </tr> | |
| <tr class="row-even"><td colspan="2"><p><strong>Trigonometric functions</strong></p></td> | |
| </tr> | |
| <tr class="row-odd"><td><p><a class="reference internal" href="#cmath.acos" title="cmath.acos"><code class="xref py py-func docutils literal notranslate"><span class="pre">acos(z)</span></code></a></p></td> | |
| <td><p>Return the arc cosine of <em>z</em></p></td> | |
| </tr> | |
| <tr class="row-even"><td><p><a class="reference internal" href="#cmath.asin" title="cmath.asin"><code class="xref py py-func docutils literal notranslate"><span class="pre">asin(z)</span></code></a></p></td> | |
| <td><p>Return the arc sine of <em>z</em></p></td> | |
| </tr> | |
| <tr class="row-odd"><td><p><a class="reference internal" href="#cmath.atan" title="cmath.atan"><code class="xref py py-func docutils literal notranslate"><span class="pre">atan(z)</span></code></a></p></td> | |
| <td><p>Return the arc tangent of <em>z</em></p></td> | |
| </tr> | |
| <tr class="row-even"><td><p><a class="reference internal" href="#cmath.cos" title="cmath.cos"><code class="xref py py-func docutils literal notranslate"><span class="pre">cos(z)</span></code></a></p></td> | |
| <td><p>Return the cosine of <em>z</em></p></td> | |
| </tr> | |
| <tr class="row-odd"><td><p><a class="reference internal" href="#cmath.sin" title="cmath.sin"><code class="xref py py-func docutils literal notranslate"><span class="pre">sin(z)</span></code></a></p></td> | |
| <td><p>Return the sine of <em>z</em></p></td> | |
| </tr> | |
| <tr class="row-even"><td><p><a class="reference internal" href="#cmath.tan" title="cmath.tan"><code class="xref py py-func docutils literal notranslate"><span class="pre">tan(z)</span></code></a></p></td> | |
| <td><p>Return the tangent of <em>z</em></p></td> | |
| </tr> | |
| <tr class="row-odd"><td colspan="2"><p><strong>Hyperbolic functions</strong></p></td> | |
| </tr> | |
| <tr class="row-even"><td><p><a class="reference internal" href="#cmath.acosh" title="cmath.acosh"><code class="xref py py-func docutils literal notranslate"><span class="pre">acosh(z)</span></code></a></p></td> | |
| <td><p>Return the inverse hyperbolic cosine of <em>z</em></p></td> | |
| </tr> | |
| <tr class="row-odd"><td><p><a class="reference internal" href="#cmath.asinh" title="cmath.asinh"><code class="xref py py-func docutils literal notranslate"><span class="pre">asinh(z)</span></code></a></p></td> | |
| <td><p>Return the inverse hyperbolic sine of <em>z</em></p></td> | |
| </tr> | |
| <tr class="row-even"><td><p><a class="reference internal" href="#cmath.atanh" title="cmath.atanh"><code class="xref py py-func docutils literal notranslate"><span class="pre">atanh(z)</span></code></a></p></td> | |
| <td><p>Return the inverse hyperbolic tangent of <em>z</em></p></td> | |
| </tr> | |
| <tr class="row-odd"><td><p><a class="reference internal" href="#cmath.cosh" title="cmath.cosh"><code class="xref py py-func docutils literal notranslate"><span class="pre">cosh(z)</span></code></a></p></td> | |
| <td><p>Return the hyperbolic cosine of <em>z</em></p></td> | |
| </tr> | |
| <tr class="row-even"><td><p><a class="reference internal" href="#cmath.sinh" title="cmath.sinh"><code class="xref py py-func docutils literal notranslate"><span class="pre">sinh(z)</span></code></a></p></td> | |
| <td><p>Return the hyperbolic sine of <em>z</em></p></td> | |
| </tr> | |
| <tr class="row-odd"><td><p><a class="reference internal" href="#cmath.tanh" title="cmath.tanh"><code class="xref py py-func docutils literal notranslate"><span class="pre">tanh(z)</span></code></a></p></td> | |
| <td><p>Return the hyperbolic tangent of <em>z</em></p></td> | |
| </tr> | |
| <tr class="row-even"><td colspan="2"><p><strong>Classification functions</strong></p></td> | |
| </tr> | |
| <tr class="row-odd"><td><p><a class="reference internal" href="#cmath.isfinite" title="cmath.isfinite"><code class="xref py py-func docutils literal notranslate"><span class="pre">isfinite(z)</span></code></a></p></td> | |
| <td><p>Check if all components of <em>z</em> are finite</p></td> | |
| </tr> | |
| <tr class="row-even"><td><p><a class="reference internal" href="#cmath.isinf" title="cmath.isinf"><code class="xref py py-func docutils literal notranslate"><span class="pre">isinf(z)</span></code></a></p></td> | |
| <td><p>Check if any component of <em>z</em> is infinite</p></td> | |
| </tr> | |
| <tr class="row-odd"><td><p><a class="reference internal" href="#cmath.isnan" title="cmath.isnan"><code class="xref py py-func docutils literal notranslate"><span class="pre">isnan(z)</span></code></a></p></td> | |
| <td><p>Check if any component of <em>z</em> is a NaN</p></td> | |
| </tr> | |
| <tr class="row-even"><td><p><a class="reference internal" href="#cmath.isclose" title="cmath.isclose"><code class="xref py py-func docutils literal notranslate"><span class="pre">isclose(a,</span> <span class="pre">b,</span> <span class="pre">*,</span> <span class="pre">rel_tol,</span> <span class="pre">abs_tol)</span></code></a></p></td> | |
| <td><p>Check if the values <em>a</em> and <em>b</em> are close to each other</p></td> | |
| </tr> | |
| <tr class="row-odd"><td colspan="2"><p><strong>Constants</strong></p></td> | |
| </tr> | |
| <tr class="row-even"><td><p><a class="reference internal" href="#cmath.pi" title="cmath.pi"><code class="xref py py-data docutils literal notranslate"><span class="pre">pi</span></code></a></p></td> | |
| <td><p><em>π</em> = 3.141592…</p></td> | |
| </tr> | |
| <tr class="row-odd"><td><p><a class="reference internal" href="#cmath.e" title="cmath.e"><code class="xref py py-data docutils literal notranslate"><span class="pre">e</span></code></a></p></td> | |
| <td><p><em>e</em> = 2.718281…</p></td> | |
| </tr> | |
| <tr class="row-even"><td><p><a class="reference internal" href="#cmath.tau" title="cmath.tau"><code class="xref py py-data docutils literal notranslate"><span class="pre">tau</span></code></a></p></td> | |
| <td><p><em>τ</em> = 2<em>π</em> = 6.283185…</p></td> | |
| </tr> | |
| <tr class="row-odd"><td><p><a class="reference internal" href="#cmath.inf" title="cmath.inf"><code class="xref py py-data docutils literal notranslate"><span class="pre">inf</span></code></a></p></td> | |
| <td><p>Positive infinity</p></td> | |
| </tr> | |
| <tr class="row-even"><td><p><a class="reference internal" href="#cmath.infj" title="cmath.infj"><code class="xref py py-data docutils literal notranslate"><span class="pre">infj</span></code></a></p></td> | |
| <td><p>Pure imaginary infinity</p></td> | |
| </tr> | |
| <tr class="row-odd"><td><p><a class="reference internal" href="#cmath.nan" title="cmath.nan"><code class="xref py py-data docutils literal notranslate"><span class="pre">nan</span></code></a></p></td> | |
| <td><p>“Not a number” (NaN)</p></td> | |
| </tr> | |
| <tr class="row-even"><td><p><a class="reference internal" href="#cmath.nanj" title="cmath.nanj"><code class="xref py py-data docutils literal notranslate"><span class="pre">nanj</span></code></a></p></td> | |
| <td><p>Pure imaginary NaN</p></td> | |
| </tr> | |
| </tbody> | |
| </table> | |
| <section id="conversions-to-and-from-polar-coordinates"> | |
| <h2>Conversions to and from polar coordinates<a class="headerlink" href="#conversions-to-and-from-polar-coordinates" title="Link to this heading">¶</a></h2> | |
| <p>A Python complex number <code class="docutils literal notranslate"><span class="pre">z</span></code> is stored internally using <em>rectangular</em> | |
| or <em>Cartesian</em> coordinates. It is completely determined by its <em>real | |
| part</em> <code class="docutils literal notranslate"><span class="pre">z.real</span></code> and its <em>imaginary part</em> <code class="docutils literal notranslate"><span class="pre">z.imag</span></code>.</p> | |
| <p><em>Polar coordinates</em> give an alternative way to represent a complex | |
| number. In polar coordinates, a complex number <em>z</em> is defined by the | |
| modulus <em>r</em> and the phase angle <em>phi</em>. The modulus <em>r</em> is the distance | |
| from <em>z</em> to the origin, while the phase <em>phi</em> is the counterclockwise | |
| angle, measured in radians, from the positive x-axis to the line | |
| segment that joins the origin to <em>z</em>.</p> | |
| <p>The following functions can be used to convert from the native | |
| rectangular coordinates to polar coordinates and back.</p> | |
| <dl class="py function"> | |
| <dt class="sig sig-object py" id="cmath.phase"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">phase</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">z</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#cmath.phase" title="Link to this definition">¶</a></dt> | |
| <dd><p>Return the phase of <em>z</em> (also known as the <em>argument</em> of <em>z</em>), as a float. | |
| <code class="docutils literal notranslate"><span class="pre">phase(z)</span></code> is equivalent to <code class="docutils literal notranslate"><span class="pre">math.atan2(z.imag,</span> <span class="pre">z.real)</span></code>. The result | |
| lies in the range [-<em>π</em>, <em>π</em>], and the branch cut for this operation lies | |
| along the negative real axis. The sign of the result is the same as the | |
| sign of <code class="docutils literal notranslate"><span class="pre">z.imag</span></code>, even when <code class="docutils literal notranslate"><span class="pre">z.imag</span></code> is zero:</p> | |
| <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">phase</span><span class="p">(</span><span class="o">-</span><span class="mi">1</span><span class="o">+</span><span class="mi">0</span><span class="n">j</span><span class="p">)</span> | |
| <span class="go">3.141592653589793</span> | |
| <span class="gp">>>> </span><span class="n">phase</span><span class="p">(</span><span class="o">-</span><span class="mi">1</span><span class="o">-</span><span class="mi">0</span><span class="n">j</span><span class="p">)</span> | |
| <span class="go">-3.141592653589793</span> | |
| </pre></div> | |
| </div> | |
| </dd></dl> | |
| <div class="admonition note"> | |
| <p class="admonition-title">Note</p> | |
| <p>The modulus (absolute value) of a complex number <em>z</em> can be | |
| computed using the built-in <a class="reference internal" href="functions.html#abs" title="abs"><code class="xref py py-func docutils literal notranslate"><span class="pre">abs()</span></code></a> function. There is no | |
| separate <code class="xref py py-mod docutils literal notranslate"><span class="pre">cmath</span></code> module function for this operation.</p> | |
| </div> | |
| <dl class="py function"> | |
| <dt class="sig sig-object py" id="cmath.polar"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">polar</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">z</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#cmath.polar" title="Link to this definition">¶</a></dt> | |
| <dd><p>Return the representation of <em>z</em> in polar coordinates. Returns a | |
| pair <code class="docutils literal notranslate"><span class="pre">(r,</span> <span class="pre">phi)</span></code> where <em>r</em> is the modulus of <em>z</em> and <em>phi</em> is the | |
| phase of <em>z</em>. <code class="docutils literal notranslate"><span class="pre">polar(z)</span></code> is equivalent to <code class="docutils literal notranslate"><span class="pre">(abs(z),</span> | |
| <span class="pre">phase(z))</span></code>.</p> | |
| </dd></dl> | |
| <dl class="py function"> | |
| <dt class="sig sig-object py" id="cmath.rect"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">rect</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">r</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">phi</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#cmath.rect" title="Link to this definition">¶</a></dt> | |
| <dd><p>Return the complex number <em>z</em> with polar coordinates <em>r</em> and <em>phi</em>. | |
| Equivalent to <code class="docutils literal notranslate"><span class="pre">complex(r</span> <span class="pre">*</span> <span class="pre">math.cos(phi),</span> <span class="pre">r</span> <span class="pre">*</span> <span class="pre">math.sin(phi))</span></code>.</p> | |
| </dd></dl> | |
| </section> | |
| <section id="power-and-logarithmic-functions"> | |
| <h2>Power and logarithmic functions<a class="headerlink" href="#power-and-logarithmic-functions" title="Link to this heading">¶</a></h2> | |
| <dl class="py function"> | |
| <dt class="sig sig-object py" id="cmath.exp"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">exp</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">z</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#cmath.exp" title="Link to this definition">¶</a></dt> | |
| <dd><p>Return <em>e</em> raised to the power <em>z</em>, where <em>e</em> is the base of natural | |
| logarithms.</p> | |
| </dd></dl> | |
| <dl class="py function"> | |
| <dt class="sig sig-object py" id="cmath.log"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">log</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">z</span></span></em><span class="optional">[</span>, <em class="sig-param"><span class="n"><span class="pre">base</span></span></em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#cmath.log" title="Link to this definition">¶</a></dt> | |
| <dd><p>Return the logarithm of <em>z</em> to the given <em>base</em>. If the <em>base</em> is not | |
| specified, returns the natural logarithm of <em>z</em>. There is one branch cut, | |
| from 0 along the negative real axis to -∞.</p> | |
| </dd></dl> | |
| <dl class="py function"> | |
| <dt class="sig sig-object py" id="cmath.log10"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">log10</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">z</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#cmath.log10" title="Link to this definition">¶</a></dt> | |
| <dd><p>Return the base-10 logarithm of <em>z</em>. This has the same branch cut as | |
| <a class="reference internal" href="#cmath.log" title="cmath.log"><code class="xref py py-func docutils literal notranslate"><span class="pre">log()</span></code></a>.</p> | |
| </dd></dl> | |
| <dl class="py function"> | |
| <dt class="sig sig-object py" id="cmath.sqrt"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">sqrt</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">z</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#cmath.sqrt" title="Link to this definition">¶</a></dt> | |
| <dd><p>Return the square root of <em>z</em>. This has the same branch cut as <a class="reference internal" href="#cmath.log" title="cmath.log"><code class="xref py py-func docutils literal notranslate"><span class="pre">log()</span></code></a>.</p> | |
| </dd></dl> | |
| </section> | |
| <section id="trigonometric-functions"> | |
| <h2>Trigonometric functions<a class="headerlink" href="#trigonometric-functions" title="Link to this heading">¶</a></h2> | |
| <dl class="py function"> | |
| <dt class="sig sig-object py" id="cmath.acos"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">acos</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">z</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#cmath.acos" title="Link to this definition">¶</a></dt> | |
| <dd><p>Return the arc cosine of <em>z</em>. There are two branch cuts: One extends right | |
| from 1 along the real axis to ∞. The other extends left from -1 along the | |
| real axis to -∞.</p> | |
| </dd></dl> | |
| <dl class="py function"> | |
| <dt class="sig sig-object py" id="cmath.asin"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">asin</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">z</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#cmath.asin" title="Link to this definition">¶</a></dt> | |
| <dd><p>Return the arc sine of <em>z</em>. This has the same branch cuts as <a class="reference internal" href="#cmath.acos" title="cmath.acos"><code class="xref py py-func docutils literal notranslate"><span class="pre">acos()</span></code></a>.</p> | |
| </dd></dl> | |
| <dl class="py function"> | |
| <dt class="sig sig-object py" id="cmath.atan"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">atan</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">z</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#cmath.atan" title="Link to this definition">¶</a></dt> | |
| <dd><p>Return the arc tangent of <em>z</em>. There are two branch cuts: One extends from | |
| <code class="docutils literal notranslate"><span class="pre">1j</span></code> along the imaginary axis to <code class="docutils literal notranslate"><span class="pre">∞j</span></code>. The other extends from <code class="docutils literal notranslate"><span class="pre">-1j</span></code> | |
| along the imaginary axis to <code class="docutils literal notranslate"><span class="pre">-∞j</span></code>.</p> | |
| </dd></dl> | |
| <dl class="py function"> | |
| <dt class="sig sig-object py" id="cmath.cos"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">cos</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">z</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#cmath.cos" title="Link to this definition">¶</a></dt> | |
| <dd><p>Return the cosine of <em>z</em>.</p> | |
| </dd></dl> | |
| <dl class="py function"> | |
| <dt class="sig sig-object py" id="cmath.sin"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">sin</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">z</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#cmath.sin" title="Link to this definition">¶</a></dt> | |
| <dd><p>Return the sine of <em>z</em>.</p> | |
| </dd></dl> | |
| <dl class="py function"> | |
| <dt class="sig sig-object py" id="cmath.tan"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">tan</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">z</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#cmath.tan" title="Link to this definition">¶</a></dt> | |
| <dd><p>Return the tangent of <em>z</em>.</p> | |
| </dd></dl> | |
| </section> | |
| <section id="hyperbolic-functions"> | |
| <h2>Hyperbolic functions<a class="headerlink" href="#hyperbolic-functions" title="Link to this heading">¶</a></h2> | |
| <dl class="py function"> | |
| <dt class="sig sig-object py" id="cmath.acosh"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">acosh</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">z</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#cmath.acosh" title="Link to this definition">¶</a></dt> | |
| <dd><p>Return the inverse hyperbolic cosine of <em>z</em>. There is one branch cut, | |
| extending left from 1 along the real axis to -∞.</p> | |
| </dd></dl> | |
| <dl class="py function"> | |
| <dt class="sig sig-object py" id="cmath.asinh"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">asinh</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">z</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#cmath.asinh" title="Link to this definition">¶</a></dt> | |
| <dd><p>Return the inverse hyperbolic sine of <em>z</em>. There are two branch cuts: | |
| One extends from <code class="docutils literal notranslate"><span class="pre">1j</span></code> along the imaginary axis to <code class="docutils literal notranslate"><span class="pre">∞j</span></code>. The other | |
| extends from <code class="docutils literal notranslate"><span class="pre">-1j</span></code> along the imaginary axis to <code class="docutils literal notranslate"><span class="pre">-∞j</span></code>.</p> | |
| </dd></dl> | |
| <dl class="py function"> | |
| <dt class="sig sig-object py" id="cmath.atanh"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">atanh</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">z</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#cmath.atanh" title="Link to this definition">¶</a></dt> | |
| <dd><p>Return the inverse hyperbolic tangent of <em>z</em>. There are two branch cuts: One | |
| extends from <code class="docutils literal notranslate"><span class="pre">1</span></code> along the real axis to <code class="docutils literal notranslate"><span class="pre">∞</span></code>. The other extends from | |
| <code class="docutils literal notranslate"><span class="pre">-1</span></code> along the real axis to <code class="docutils literal notranslate"><span class="pre">-∞</span></code>.</p> | |
| </dd></dl> | |
| <dl class="py function"> | |
| <dt class="sig sig-object py" id="cmath.cosh"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">cosh</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">z</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#cmath.cosh" title="Link to this definition">¶</a></dt> | |
| <dd><p>Return the hyperbolic cosine of <em>z</em>.</p> | |
| </dd></dl> | |
| <dl class="py function"> | |
| <dt class="sig sig-object py" id="cmath.sinh"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">sinh</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">z</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#cmath.sinh" title="Link to this definition">¶</a></dt> | |
| <dd><p>Return the hyperbolic sine of <em>z</em>.</p> | |
| </dd></dl> | |
| <dl class="py function"> | |
| <dt class="sig sig-object py" id="cmath.tanh"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">tanh</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">z</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#cmath.tanh" title="Link to this definition">¶</a></dt> | |
| <dd><p>Return the hyperbolic tangent of <em>z</em>.</p> | |
| </dd></dl> | |
| </section> | |
| <section id="classification-functions"> | |
| <h2>Classification functions<a class="headerlink" href="#classification-functions" title="Link to this heading">¶</a></h2> | |
| <dl class="py function"> | |
| <dt class="sig sig-object py" id="cmath.isfinite"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">isfinite</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">z</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#cmath.isfinite" title="Link to this definition">¶</a></dt> | |
| <dd><p>Return <code class="docutils literal notranslate"><span class="pre">True</span></code> if both the real and imaginary parts of <em>z</em> are finite, and | |
| <code class="docutils literal notranslate"><span class="pre">False</span></code> otherwise.</p> | |
| <div class="versionadded"> | |
| <p><span class="versionmodified added">Added in version 3.2.</span></p> | |
| </div> | |
| </dd></dl> | |
| <dl class="py function"> | |
| <dt class="sig sig-object py" id="cmath.isinf"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">isinf</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">z</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#cmath.isinf" title="Link to this definition">¶</a></dt> | |
| <dd><p>Return <code class="docutils literal notranslate"><span class="pre">True</span></code> if either the real or the imaginary part of <em>z</em> is an | |
| infinity, and <code class="docutils literal notranslate"><span class="pre">False</span></code> otherwise.</p> | |
| </dd></dl> | |
| <dl class="py function"> | |
| <dt class="sig sig-object py" id="cmath.isnan"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">isnan</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">z</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#cmath.isnan" title="Link to this definition">¶</a></dt> | |
| <dd><p>Return <code class="docutils literal notranslate"><span class="pre">True</span></code> if either the real or the imaginary part of <em>z</em> is a NaN, | |
| and <code class="docutils literal notranslate"><span class="pre">False</span></code> otherwise.</p> | |
| </dd></dl> | |
| <dl class="py function"> | |
| <dt class="sig sig-object py" id="cmath.isclose"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">isclose</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">a</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">b</span></span></em>, <em class="sig-param"><span class="keyword-only-separator o"><abbr title="Keyword-only parameters separator (PEP 3102)"><span class="pre">*</span></abbr></span></em>, <em class="sig-param"><span class="n"><span class="pre">rel_tol</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">1e-09</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">abs_tol</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">0.0</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#cmath.isclose" title="Link to this definition">¶</a></dt> | |
| <dd><p>Return <code class="docutils literal notranslate"><span class="pre">True</span></code> if the values <em>a</em> and <em>b</em> are close to each other and | |
| <code class="docutils literal notranslate"><span class="pre">False</span></code> otherwise.</p> | |
| <p>Whether or not two values are considered close is determined according to | |
| given absolute and relative tolerances. If no errors occur, the result will | |
| be: <code class="docutils literal notranslate"><span class="pre">abs(a-b)</span> <span class="pre"><=</span> <span class="pre">max(rel_tol</span> <span class="pre">*</span> <span class="pre">max(abs(a),</span> <span class="pre">abs(b)),</span> <span class="pre">abs_tol)</span></code>.</p> | |
| <p><em>rel_tol</em> is the relative tolerance – it is the maximum allowed difference | |
| between <em>a</em> and <em>b</em>, relative to the larger absolute value of <em>a</em> or <em>b</em>. | |
| For example, to set a tolerance of 5%, pass <code class="docutils literal notranslate"><span class="pre">rel_tol=0.05</span></code>. The default | |
| tolerance is <code class="docutils literal notranslate"><span class="pre">1e-09</span></code>, which assures that the two values are the same | |
| within about 9 decimal digits. <em>rel_tol</em> must be nonnegative and less | |
| than <code class="docutils literal notranslate"><span class="pre">1.0</span></code>.</p> | |
| <p><em>abs_tol</em> is the absolute tolerance; it defaults to <code class="docutils literal notranslate"><span class="pre">0.0</span></code> and it must be | |
| nonnegative. When comparing <code class="docutils literal notranslate"><span class="pre">x</span></code> to <code class="docutils literal notranslate"><span class="pre">0.0</span></code>, <code class="docutils literal notranslate"><span class="pre">isclose(x,</span> <span class="pre">0)</span></code> is computed | |
| as <code class="docutils literal notranslate"><span class="pre">abs(x)</span> <span class="pre"><=</span> <span class="pre">rel_tol</span>  <span class="pre">*</span> <span class="pre">abs(x)</span></code>, which is <code class="docutils literal notranslate"><span class="pre">False</span></code> for any <code class="docutils literal notranslate"><span class="pre">x</span></code> and | |
| rel_tol less than <code class="docutils literal notranslate"><span class="pre">1.0</span></code>. So add an appropriate positive abs_tol argument | |
| to the call.</p> | |
| <p>The IEEE 754 special values of <code class="docutils literal notranslate"><span class="pre">NaN</span></code>, <code class="docutils literal notranslate"><span class="pre">inf</span></code>, and <code class="docutils literal notranslate"><span class="pre">-inf</span></code> will be | |
| handled according to IEEE rules. Specifically, <code class="docutils literal notranslate"><span class="pre">NaN</span></code> is not considered | |
| close to any other value, including <code class="docutils literal notranslate"><span class="pre">NaN</span></code>. <code class="docutils literal notranslate"><span class="pre">inf</span></code> and <code class="docutils literal notranslate"><span class="pre">-inf</span></code> are only | |
| considered close to themselves.</p> | |
| <div class="versionadded"> | |
| <p><span class="versionmodified added">Added in version 3.5.</span></p> | |
| </div> | |
| <div class="admonition seealso"> | |
| <p class="admonition-title">See also</p> | |
| <p><span class="target" id="index-0"></span><a class="pep reference external" href="https://peps.python.org/pep-0485/"><strong>PEP 485</strong></a> – A function for testing approximate equality</p> | |
| </div> | |
| </dd></dl> | |
| </section> | |
| <section id="constants"> | |
| <h2>Constants<a class="headerlink" href="#constants" title="Link to this heading">¶</a></h2> | |
| <dl class="py data"> | |
| <dt class="sig sig-object py" id="cmath.pi"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">pi</span></span><a class="headerlink" href="#cmath.pi" title="Link to this definition">¶</a></dt> | |
| <dd><p>The mathematical constant <em>π</em>, as a float.</p> | |
| </dd></dl> | |
| <dl class="py data"> | |
| <dt class="sig sig-object py" id="cmath.e"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">e</span></span><a class="headerlink" href="#cmath.e" title="Link to this definition">¶</a></dt> | |
| <dd><p>The mathematical constant <em>e</em>, as a float.</p> | |
| </dd></dl> | |
| <dl class="py data"> | |
| <dt class="sig sig-object py" id="cmath.tau"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">tau</span></span><a class="headerlink" href="#cmath.tau" title="Link to this definition">¶</a></dt> | |
| <dd><p>The mathematical constant <em>τ</em>, as a float.</p> | |
| <div class="versionadded"> | |
| <p><span class="versionmodified added">Added in version 3.6.</span></p> | |
| </div> | |
| </dd></dl> | |
| <dl class="py data"> | |
| <dt class="sig sig-object py" id="cmath.inf"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">inf</span></span><a class="headerlink" href="#cmath.inf" title="Link to this definition">¶</a></dt> | |
| <dd><p>Floating-point positive infinity. Equivalent to <code class="docutils literal notranslate"><span class="pre">float('inf')</span></code>.</p> | |
| <div class="versionadded"> | |
| <p><span class="versionmodified added">Added in version 3.6.</span></p> | |
| </div> | |
| </dd></dl> | |
| <dl class="py data"> | |
| <dt class="sig sig-object py" id="cmath.infj"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">infj</span></span><a class="headerlink" href="#cmath.infj" title="Link to this definition">¶</a></dt> | |
| <dd><p>Complex number with zero real part and positive infinity imaginary | |
| part. Equivalent to <code class="docutils literal notranslate"><span class="pre">complex(0.0,</span> <span class="pre">float('inf'))</span></code>.</p> | |
| <div class="versionadded"> | |
| <p><span class="versionmodified added">Added in version 3.6.</span></p> | |
| </div> | |
| </dd></dl> | |
| <dl class="py data"> | |
| <dt class="sig sig-object py" id="cmath.nan"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">nan</span></span><a class="headerlink" href="#cmath.nan" title="Link to this definition">¶</a></dt> | |
| <dd><p>A floating-point “not a number” (NaN) value. Equivalent to | |
| <code class="docutils literal notranslate"><span class="pre">float('nan')</span></code>. See also <a class="reference internal" href="math.html#math.nan" title="math.nan"><code class="xref py py-data docutils literal notranslate"><span class="pre">math.nan</span></code></a>.</p> | |
| <div class="versionadded"> | |
| <p><span class="versionmodified added">Added in version 3.6.</span></p> | |
| </div> | |
| </dd></dl> | |
| <dl class="py data"> | |
| <dt class="sig sig-object py" id="cmath.nanj"> | |
| <span class="sig-prename descclassname"><span class="pre">cmath.</span></span><span class="sig-name descname"><span class="pre">nanj</span></span><a class="headerlink" href="#cmath.nanj" title="Link to this definition">¶</a></dt> | |
| <dd><p>Complex number with zero real part and NaN imaginary part. Equivalent to | |
| <code class="docutils literal notranslate"><span class="pre">complex(0.0,</span> <span class="pre">float('nan'))</span></code>.</p> | |
| <div class="versionadded"> | |
| <p><span class="versionmodified added">Added in version 3.6.</span></p> | |
| </div> | |
| </dd></dl> | |
| <p id="index-1">Note that the selection of functions is similar, but not identical, to that in | |
| module <a class="reference internal" href="math.html#module-math" title="math: Mathematical functions (sin() etc.)."><code class="xref py py-mod docutils literal notranslate"><span class="pre">math</span></code></a>. The reason for having two modules is that some users aren’t | |
| interested in complex numbers, and perhaps don’t even know what they are. They | |
| would rather have <code class="docutils literal notranslate"><span class="pre">math.sqrt(-1)</span></code> raise an exception than return a complex | |
| number. Also note that the functions defined in <code class="xref py py-mod docutils literal notranslate"><span class="pre">cmath</span></code> always return a | |
| complex number, even if the answer can be expressed as a real number (in which | |
| case the complex number has an imaginary part of zero).</p> | |
| <p>A note on branch cuts: They are curves along which the given function fails to | |
| be continuous. They are a necessary feature of many complex functions. It is | |
| assumed that if you need to compute with complex functions, you will understand | |
| about branch cuts. Consult almost any (not too elementary) book on complex | |
| variables for enlightenment. For information of the proper choice of branch | |
| cuts for numerical purposes, a good reference should be the following:</p> | |
| <div class="admonition seealso"> | |
| <p class="admonition-title">See also</p> | |
| <p>Kahan, W: Branch cuts for complex elementary functions; or, Much ado about | |
| nothing’s sign bit. In Iserles, A., and Powell, M. (eds.), The state of the art | |
| in numerical analysis. Clarendon Press (1987) pp165–211.</p> | |
| </div> | |
| </section> | |
| </section> | |
| <div class="clearer"></div> | |
| </div> | |
| </div> | |
| </div> | |
| <div class="sphinxsidebar" role="navigation" aria-label="Main"> | |
| <div class="sphinxsidebarwrapper"> | |
| <div> | |
| <h3><a href="../contents.html">Table of Contents</a></h3> | |
| <ul> | |
| <li><a class="reference internal" href="#"><code class="xref py py-mod docutils literal notranslate"><span class="pre">cmath</span></code> — Mathematical functions for complex numbers</a><ul> | |
| <li><a class="reference internal" href="#conversions-to-and-from-polar-coordinates">Conversions to and from polar coordinates</a></li> | |
| <li><a class="reference internal" href="#power-and-logarithmic-functions">Power and logarithmic functions</a></li> | |
| <li><a class="reference internal" href="#trigonometric-functions">Trigonometric functions</a></li> | |
| <li><a class="reference internal" href="#hyperbolic-functions">Hyperbolic functions</a></li> | |
| <li><a class="reference internal" href="#classification-functions">Classification functions</a></li> | |
| <li><a class="reference internal" href="#constants">Constants</a></li> | |
| </ul> | |
| </li> | |
| </ul> | |
| </div> | |
| <div> | |
| <h4>Previous topic</h4> | |
| <p class="topless"><a href="math.integer.html" | |
| title="previous chapter"><code class="xref py py-mod docutils literal notranslate"><span class="pre">math.integer</span></code> — integer-specific mathematics functions</a></p> | |
| </div> | |
| <div> | |
| <h4>Next topic</h4> | |
| <p class="topless"><a href="decimal.html" | |
| title="next chapter"><code class="xref py py-mod docutils literal notranslate"><span class="pre">decimal</span></code> — Decimal fixed-point and floating-point arithmetic</a></p> | |
| </div> | |
| <script> | |
| document.addEventListener('DOMContentLoaded', () => { | |
| const title = document.querySelector('meta[property="og:title"]').content; | |
| const elements = document.querySelectorAll('.improvepage'); | |
| const pageurl = window.location.href.split('?')[0]; | |
| elements.forEach(element => { | |
| const url = new URL(element.href.split('?')[0].replace("-nojs", "")); | |
| url.searchParams.set('pagetitle', title); | |
| url.searchParams.set('pageurl', pageurl); | |
| url.searchParams.set('pagesource', "library/cmath.rst"); | |
| element.href = url.toString(); | |
| }); | |
| }); | |
| </script> | |
| <div role="note" aria-label="source link"> | |
| <h3>This page</h3> | |
| <ul class="this-page-menu"> | |
| <li><a href="../bugs.html">Report a bug</a></li> | |
| <li><a class="improvepage" href="../improve-page-nojs.html">Improve this page</a></li> | |
| <li> | |
| <a href="https://github.com/python/cpython/blob/main/Doc/library/cmath.rst?plain=1" | |
| rel="nofollow">Show source | |
| </a> | |
| </li> | |
| </ul> | |
| </div> | |
| </div> | |
| <div id="sidebarbutton" title="Collapse sidebar"> | |
| <span>«</span> | |
| </div> | |
| </div> | |
| <div class="clearer"></div> | |
| </div> | |
| <div class="related" role="navigation" aria-label="Related"> | |
| <h3>Navigation</h3> | |
| <ul> | |
| <li class="right" style="margin-right: 10px"> | |
| <a href="../genindex.html" title="General Index" | |
| >index</a></li> | |
| <li class="right" > | |
| <a href="../py-modindex.html" title="Python Module Index" | |
| >modules</a> |</li> | |
| <li class="right" > | |
| <a href="decimal.html" title="decimal — Decimal fixed-point and floating-point arithmetic" | |
| >next</a> |</li> | |
| <li class="right" > | |
| <a href="math.integer.html" title="math.integer — integer-specific mathematics functions" | |
| >previous</a> |</li> | |
| <li><img src="../_static/py.svg" alt="Python logo" style="vertical-align: middle; margin-top: -1px"></li> | |
| <li><a href="https://www.python.org/">Python</a> »</li> | |
| <li class="switchers"> | |
| <div class="language_switcher_placeholder"></div> | |
| <div class="version_switcher_placeholder"></div> | |
| </li> | |
| <li> | |
| </li> | |
| <li id="cpython-language-and-version"> | |
| <a href="../index.html">3.15.0a6 Documentation</a> » | |
| </li> | |
| <li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> »</li> | |
| <li class="nav-item nav-item-2"><a href="numeric.html" >Numeric and Mathematical Modules</a> »</li> | |
| <li class="nav-item nav-item-this"><a href=""><code class="xref py py-mod docutils literal notranslate"><span class="pre">cmath</span></code> — Mathematical functions for complex numbers</a></li> | |
| <li class="right"> | |
| <div class="inline-search" role="search"> | |
| <form class="inline-search" action="../search.html" method="get"> | |
| <input placeholder="Quick search" aria-label="Quick search" type="search" name="q" id="search-box"> | |
| <input type="submit" value="Go"> | |
| </form> | |
| </div> | |
| | | |
| </li> | |
| <li class="right"> | |
| <label class="theme-selector-label"> | |
| Theme | |
| <select class="theme-selector" oninput="activateTheme(this.value)"> | |
| <option value="auto" selected>Auto</option> | |
| <option value="light">Light</option> | |
| <option value="dark">Dark</option> | |
| </select> | |
| </label> |</li> | |
| </ul> | |
| </div> | |
| <div class="footer"> | |
| © <a href="../copyright.html">Copyright</a> 2001 Python Software Foundation. | |
| <br> | |
| This page is licensed under the Python Software Foundation License Version 2. | |
| <br> | |
| Examples, recipes, and other code in the documentation are additionally licensed under the Zero Clause BSD License. | |
| <br> | |
| See <a href="/license.html">History and License</a> for more information.<br> | |
| <br> | |
| The Python Software Foundation is a non-profit corporation. | |
| <a href="https://www.python.org/psf/donations/">Please donate.</a> | |
| <br> | |
| <br> | |
| Last updated on Mar 10, 2026 (08:58 UTC). | |
| <a href="/bugs.html">Found a bug</a>? | |
| <br> | |
| Created using <a href="https://www.sphinx-doc.org/">Sphinx</a> 8.2.3. | |
| </div> | |
| </body> | |
| </html> |