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diff --git a/libstdc++-v3/doc/xml/manual/numerics.xml b/libstdc++-v3/doc/xml/manual/numerics.xml new file mode 100644 index 000000000..a9e866e78 --- /dev/null +++ b/libstdc++-v3/doc/xml/manual/numerics.xml @@ -0,0 +1,145 @@ +<chapter xmlns="http://docbook.org/ns/docbook" version="5.0" + xml:id="std.numerics" xreflabel="Numerics"> +<?dbhtml filename="numerics.html"?> + +<info><title> + Numerics + <indexterm><primary>Numerics</primary></indexterm> +</title> + <keywordset> + <keyword> + ISO C++ + </keyword> + <keyword> + library + </keyword> + </keywordset> +</info> + + + +<!-- Sect1 01 : Complex --> +<section xml:id="std.numerics.complex" xreflabel="complex"><info><title>Complex</title></info> +<?dbhtml filename="complex.html"?> + + <para> + </para> + <section xml:id="numerics.complex.processing" xreflabel="complex Processing"><info><title>complex Processing</title></info> + + <para> + </para> + <para>Using <code>complex<></code> becomes even more comple- er, sorry, + <emphasis>complicated</emphasis>, with the not-quite-gratuitously-incompatible + addition of complex types to the C language. David Tribble has + compiled a list of C++98 and C99 conflict points; his description of + C's new type versus those of C++ and how to get them playing together + nicely is +<link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://david.tribble.com/text/cdiffs.htm#C99-complex">here</link>. + </para> + <para><code>complex<></code> is intended to be instantiated with a + floating-point type. As long as you meet that and some other basic + requirements, then the resulting instantiation has all of the usual + math operators defined, as well as definitions of <code>op<<</code> + and <code>op>></code> that work with iostreams: <code>op<<</code> + prints <code>(u,v)</code> and <code>op>></code> can read <code>u</code>, + <code>(u)</code>, and <code>(u,v)</code>. + </para> + + </section> +</section> + +<!-- Sect1 02 : Generalized Operations --> +<section xml:id="std.numerics.generalized_ops" xreflabel="Generalized Ops"><info><title>Generalized Operations</title></info> +<?dbhtml filename="generalized_numeric_operations.html"?> + + <para> + </para> + + <para>There are four generalized functions in the <numeric> header + that follow the same conventions as those in <algorithm>. Each + of them is overloaded: one signature for common default operations, + and a second for fully general operations. Their names are + self-explanatory to anyone who works with numerics on a regular basis: + </para> + <itemizedlist> + <listitem><para><code>accumulate</code></para></listitem> + <listitem><para><code>inner_product</code></para></listitem> + <listitem><para><code>chapterial_sum</code></para></listitem> + <listitem><para><code>adjacent_difference</code></para></listitem> + </itemizedlist> + <para>Here is a simple example of the two forms of <code>accumulate</code>. + </para> + <programlisting> + int ar[50]; + int someval = somefunction(); + + // ...initialize members of ar to something... + + int sum = std::accumulate(ar,ar+50,0); + int sum_stuff = std::accumulate(ar,ar+50,someval); + int product = std::accumulate(ar,ar+50,1,std::multiplies<int>()); + </programlisting> + <para>The first call adds all the members of the array, using zero as an + initial value for <code>sum</code>. The second does the same, but uses + <code>someval</code> as the starting value (thus, <code>sum_stuff == sum + + someval</code>). The final call uses the second of the two signatures, + and multiplies all the members of the array; here we must obviously + use 1 as a starting value instead of 0. + </para> + <para>The other three functions have similar dual-signature forms. + </para> + +</section> + +<!-- Sect1 03 : Interacting with C --> +<section xml:id="std.numerics.c" xreflabel="Interacting with C"><info><title>Interacting with C</title></info> +<?dbhtml filename="numerics_and_c.html"?> + + + <section xml:id="numerics.c.array" xreflabel="Numerics vs. Arrays"><info><title>Numerics vs. Arrays</title></info> + + + <para>One of the major reasons why FORTRAN can chew through numbers so well + is that it is defined to be free of pointer aliasing, an assumption + that C89 is not allowed to make, and neither is C++98. C99 adds a new + keyword, <code>restrict</code>, to apply to individual pointers. The + C++ solution is contained in the library rather than the language + (although many vendors can be expected to add this to their compilers + as an extension). + </para> + <para>That library solution is a set of two classes, five template classes, + and "a whole bunch" of functions. The classes are required + to be free of pointer aliasing, so compilers can optimize the + daylights out of them the same way that they have been for FORTRAN. + They are collectively called <code>valarray</code>, although strictly + speaking this is only one of the five template classes, and they are + designed to be familiar to people who have worked with the BLAS + libraries before. + </para> + + </section> + + <section xml:id="numerics.c.c99" xreflabel="C99"><info><title>C99</title></info> + + + <para>In addition to the other topics on this page, we'll note here some + of the C99 features that appear in libstdc++. + </para> + <para>The C99 features depend on the <code>--enable-c99</code> configure flag. + This flag is already on by default, but it can be disabled by the + user. Also, the configuration machinery will disable it if the + necessary support for C99 (e.g., header files) cannot be found. + </para> + <para>As of GCC 3.0, C99 support includes classification functions + such as <code>isnormal</code>, <code>isgreater</code>, + <code>isnan</code>, etc. + The functions used for 'long long' support such as <code>strtoll</code> + are supported, as is the <code>lldiv_t</code> typedef. Also supported + are the wide character functions using 'long long', like + <code>wcstoll</code>. + </para> + + </section> +</section> + +</chapter> |