* Bug #14219 fixed - As bug #14203, improve some error messages, some help pages...
[scilab.git] / scilab / modules / umfpack / help / en_US / umf_lusolve.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" 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="umf_lusolve">
3     <refnamediv>
4         <refname>umf_lusolve</refname>
5         <refpurpose>solve a linear sparse system given the LU factors  </refpurpose>
6     </refnamediv>
7     <refsynopsisdiv>
8         <title>Calling Sequence</title>
9         <synopsis>[x] = umf_lusolve(LU_ptr, b [, st, A])</synopsis>
10     </refsynopsisdiv>
11     <refsection>
12         <title>Arguments</title>
13         <variablelist>
14             <varlistentry>
15                 <term>LU_ptr  </term>
16                 <listitem>
17                     <para>a pointer to umf lu factors (L,U,p,q,R) </para>
18                 </listitem>
19             </varlistentry>
20             <varlistentry>
21                 <term>b  </term>
22                 <listitem>
23                     <para>a real or complex column vector or a matrix (multiple rhs)</para>
24                 </listitem>
25             </varlistentry>
26             <varlistentry>
27                 <term>st  </term>
28                 <listitem>
29                     <para>(optional) a string "Ax=b" (default) or "Ax'=b" 
30                         (to be written "Ax''=b"  in scilab langage: a quote in a string
31                         must be doubled !)
32                     </para>
33                 </listitem>
34             </varlistentry>
35             <varlistentry>
36                 <term>A  </term>
37                 <listitem>
38                     <para>(optional) the sparse square matrix corresponding to the LU factors (LU_ptr must be got with LU_ptr = umf_lufact(A))</para>
39                 </listitem>
40             </varlistentry>
41             <varlistentry>
42                 <term>x  </term>
43                 <listitem>
44                     <para>a column vector or a matrix in case of multiple rhs ( x(:,i) is solution of A x(:,i) = b(:,i) or A'x(:,i) = b(:,i) )</para>
45                 </listitem>
46             </varlistentry>
47         </variablelist>
48     </refsection>
49     <refsection>
50         <title>Description</title>
51         <para>
52             This function must be used in conjunction with <link linkend="umf_lufact">umf_lufact</link> which
53             computes the LU factors of a sparse matrix. The optional
54             <literal>st</literal> argument lets us choose between the solving of Ax=b (general case)
55             or of A'x=b (sometimes useful). If you give the 4th argument then
56             iterative refinement will be also proceeded (as in umfpack) to
57             give a better numerical solution. 
58         </para>
59     </refsection>
60     <refsection>
61         <title>Examples</title>
62         <para>
63             see the example section of <link linkend="umf_lufact">umf_lufact</link>
64         </para>
65     </refsection>
66     <refsection role="see also">
67         <title>See Also</title>
68         <simplelist type="inline">
69             <member>
70                 <link linkend="umfpack">umfpack</link>
71             </member>
72             <member>
73                 <link linkend="umf_lufact">umf_lufact</link>
74             </member>
75             <member>
76                 <link linkend="umf_luget">umf_luget</link>
77             </member>
78             <member>
79                 <link linkend="umf_ludel">umf_ludel</link>
80             </member>
81             <member>
82                 <link linkend="umf_luinfo">umf_luinfo</link>
83             </member>
84         </simplelist>
85     </refsection>
86 </refentry>