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沈唁
87 lines
2.5 KiB
XML
87 lines
2.5 KiB
XML
<?xml version="1.0" encoding="utf-8"?>
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<!-- $Revision$ -->
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<!-- EN-Revision: 26ce97891946b6ce1d7e79c171802a447e1eea34 Maintainer: yincheng Status: ready -->
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<!-- CREDITS: mowangjuanzi, Luffy -->
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<refentry xml:id="function.log" xmlns="http://docbook.org/ns/docbook">
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<refnamediv>
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<refname>log</refname>
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<refpurpose>自然对数</refpurpose>
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</refnamediv>
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<refsect1 role="description">
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&reftitle.description;
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<methodsynopsis>
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<type>float</type><methodname>log</methodname>
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<methodparam><type>float</type><parameter>num</parameter></methodparam>
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<methodparam choice="opt"><type>float</type><parameter>base</parameter><initializer><constant>M_E</constant></initializer></methodparam>
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</methodsynopsis>
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<para>
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如果指定了可选的参数 <parameter>base</parameter>，<function>log</function>
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返回 log<subscript>base</subscript>
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<parameter>num</parameter>，否则 <function>log</function>
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返回参数 <parameter>num</parameter> 的自然对数。
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</para>
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</refsect1>
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<refsect1 role="parameters">
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&reftitle.parameters;
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<para>
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<variablelist>
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<varlistentry>
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<term><parameter>num</parameter></term>
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<listitem>
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<para>
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要计算对数的值
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>base</parameter></term>
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<listitem>
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<para>
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可选的底数（默认是“e”，也可以说是自然对数）。
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</para>
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</refsect1>
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<refsect1 role="returnvalues">
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&reftitle.returnvalues;
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<para>
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以 <parameter>base</parameter> 为底
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<parameter>num</parameter> 的对数，如果未指定
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<parameter>num</parameter> 则为自然对数。
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</para>
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</refsect1>
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<refsect1 role="seealso">
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&reftitle.seealso;
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<para>
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<simplelist>
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<member><function>log10</function></member>
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<member><function>exp</function></member>
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<member><function>pow</function></member>
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<member><function>error_log</function></member>
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</simplelist>
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</para>
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</refsect1>
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</refentry>
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<!-- Keep this comment at the end of the file
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Local variables:
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mode: sgml
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sgml-omittag:t
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sgml-shorttag:t
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sgml-minimize-attributes:nil
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sgml-always-quote-attributes:t
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sgml-indent-step:1
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sgml-indent-data:t
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indent-tabs-mode:nil
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sgml-parent-document:nil
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sgml-default-dtd-file:"~/.phpdoc/manual.ced"
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sgml-exposed-tags:nil
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sgml-local-catalogs:nil
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sgml-local-ecat-files:nil
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End:
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vim600: syn=xml fen fdm=syntax fdl=2 si
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vim: et tw=78 syn=sgml
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vi: ts=1 sw=1
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-->
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