scilab/modules/data_structures/help/en_US/boolean.xml

   1 <?xml version="1.0" encoding="UTF-8"?>
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  13 <refentry xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:svg="http://www.w3.org/2000/svg" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:db="http://docbook.org/ns/docbook" xmlns:scilab="http://www.scilab.org" xml:lang="en" xml:id="boolean">
  14     <refnamediv>
  15         <refname>boolean</refname>
  16         <refpurpose>Scilab Objects, boolean variables and operators &amp; | ~  </refpurpose>
  17     </refnamediv>
  18     <refsection>
  19         <title>Description</title>
  20         <para>
  21             A boolean variable is <constant>%T</constant> (for "true") or <constant>%F</constant> (for "false"). These variables can be used to define matrices of booleans, with the usual syntax. Boolean matrices can be manipulated as ordinary matrices for elements extraction/insertion and concatenation. Note that other usual operations (<literal>+</literal>, <literal>*</literal>, <literal>-</literal>, <literal>^</literal>, etc) are undefined for boolean matrices. Three special operators are defined for boolean matrices:
  22         </para>
  23         <variablelist>
  24             <varlistentry>
  25                 <term>~b</term>
  26                 <listitem>
  27                     <para>
  28                         is the element-wise negation of boolean <literal>b</literal> (matrix).
  29                     </para>
  30                 </listitem>
  31             </varlistentry>
  32             <varlistentry>
  33                 <term>b1 &amp; b2</term>
  34                 <listitem>
  35                     <para>
  36                         is the element-wise logical <literal>and</literal> of
  37                         <literal>b1</literal> and <literal>b2</literal>
  38                         (matrices).
  39                     </para>
  40                 </listitem>
  41             </varlistentry>
  42             <varlistentry>
  43                 <term>b1 | b2</term>
  44                 <listitem>
  45                     <para>
  46                         is the  element-wise logical
  47                         <literal>or</literal> of <literal>b1</literal>
  48                         and <literal>b2</literal> (matrices).
  49                     </para>
  50                 </listitem>
  51             </varlistentry>
  52         </variablelist>
  53         <para>
  54             Boolean variables can be used for indexing matrices or vectors. For instance <code>a([%T,%F,%T],:)</code> returns the submatrix made of rows <literal>1</literal> and <literal>3</literal> of <literal>a</literal>. Boolean sparse matrices are supported.
  55         </para>
  56     </refsection>
  57     <refsection>
  58         <title>Examples</title>
  59         <programlisting role="example"><![CDATA[
  60 [1,2]==[1,3]
  61 [1,2]==1
  62 a=1:5; a(a>2)
  63 ]]></programlisting>
  64     </refsection>
  65     <refsection role="see also">
  66         <title>See Also</title>
  67         <simplelist type="inline">
  68             <member>
  69                 <link linkend="matrices">matrices</link>
  70             </member>
  71             <member>
  72                 <link linkend="or">or</link>
  73             </member>
  74             <member>
  75                 <link linkend="and">and</link>
  76             </member>
  77             <member>
  78                 <link linkend="not">not</link>
  79             </member>
  80         </simplelist>
  81     </refsection>
  82 </refentry>