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>Syntax</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 language: 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>