[fileio] fileparts() unit tests extended
[scilab.git] / scilab / modules / elementary_functions / help / pt_BR / elementarymatrices / empty.xml
1 <?xml version="1.0" encoding="UTF-8"?>
2 <refentry xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink"
3           xmlns:svg="http://www.w3.org/2000/svg" xmlns:ns5="http://www.w3.org/1999/xhtml"
4           xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:db="http://docbook.org/ns/docbook"
5           xmlns:scilab="http://www.scilab.org" xml:id="empty" xml:lang="pt">
6     <refnamediv>
7         <refname>empty</refname>
8         <refpurpose>([]) matriz vazia</refpurpose>
9     </refnamediv>
10     <refsection>
11         <title>Descrição</title>
12         <para>
13             <literal> [] </literal> denota a matriz vazia. É definida de modo
14             único e possui 0 linha e 0 coluna, i.e. <literal> size([]) =[0,0]
15             </literal>
16             .As seguintes convenções convenientes foram feitas:
17         </para>
18         <para>
19             <literal> [] * A = A * [] = [] </literal>
20         </para>
21         <para>
22             <literal> [] + A = A + [] = [] </literal>
23         </para>
24         <para>
25             <literal> [ [], A] = [A, []] = A </literal>
26         </para>
27         <para>
28             Funções de matrizes retornam <literal>[]</literal> ou produzem uma
29             mensagem de erro quando não há resposta óbvia. Sistemas lineares vazios
30             (listas<literal> syslin</literal>) podem ter várias linhas ou
31             colunas.
32         </para>
33     </refsection>
34     <refsection>
35         <title>Exemplos</title>
36         <programlisting role="example"><![CDATA[
37 s=poly(0,'s');
38 A = [s, s+1];
39 A+[], A*[]
40 A=rand(2,2);
41 AA=A([],1), size(AA)
42 svd([])
43 w=ssrand(2,2,2);
44 wr=[]*w;
45 size(wr), w1=ss2tf(wr), size(w1)
46  ]]></programlisting>
47     </refsection>
48     <refsection role="see also">
49         <title>Ver Também</title>
50         <simplelist type="inline">
51             <member>
52                 <link linkend="null">null</link>
53             </member>
54             <member>
55                 <link linkend="isempty">isempty</link>
56             </member>
57             <member>
58                 <link linkend="emptystr">emptystr</link>
59             </member>
60             <member>
61                 <link linkend="brackets">brackets</link>
62             </member>
63             <member>
64                 <link linkend="symbols">operators</link>
65             </member>
66             <member>
67                 <link linkend="matrices">matrices</link>
68             </member>
69         </simplelist>
70     </refsection>
71     <refsection>
72         <title>Histórico</title>
73         <revhistory>
74             <revision>
75                 <revnumber>6.0.0</revnumber>
76                 <revremark>
77                     <itemizedlist>
78                       <listitem>
79                           <literal>A+[]</literal>, <literal>[]+A</literal> and <literal>A-[]</literal>
80                           now return <literal>[]</literal> instead of <literal>A</literal>.
81                           <literal>[]-A</literal> now returns <literal>[]</literal> instead of
82                           <literal>-A</literal>.
83                       </listitem>
84                       <listitem>
85                          <literal> A>[] </literal>, <literal> A>=[] </literal>,
86                          <literal> A&lt;[] </literal>, <literal> A&lt;=[] </literal>,
87                          <literal> []>A </literal>, <literal> []>=A </literal>,
88                          <literal> []&lt;A </literal>, and <literal> []&lt;=A </literal> now return
89                          <literal> [] </literal> instead of an error.
90                       </listitem>
91                     </itemizedlist>
92                 </revremark>
93             </revision>
94         </revhistory>
95     </refsection>
96 </refentry>