* Bug #13531 fixed - Fixed sylv help page to include the real Sylester equation.

[scilab.git] / scilab / modules / linear_algebra / help / en_US / pencil / sylv.xml

diff --git a/scilab/modules/linear_algebra/help/en_US/pencil/sylv.xml b/scilab/modules/linear_algebra/help/en_US/pencil/sylv.xml
index 229a116..4b6d859 100644 (file)
--- a/scilab/modules/linear_algebra/help/en_US/pencil/sylv.xml
+++ b/scilab/modules/linear_algebra/help/en_US/pencil/sylv.xml
@@ -2,11 +2,11 @@
 <!--
  * Scilab ( http://www.scilab.org/ ) - This file is part of Scilab
  * Copyright (C) 2008 - INRIA
- * 
+ *
  * This file must be used under the terms of the CeCILL.
  * This source file is licensed as described in the file COPYING, which
  * you should have received as part of this distribution.  The terms
- * are also available at    
+ * are also available at
  * http://www.cecill.info/licences/Licence_CeCILL_V2.1-en.txt
  *
  -->
@@ -49,19 +49,33 @@ A*X+X*B = C
  ]]></programlisting>
         <para>
             <literal>X=sylv(A, B, C, 'd')</literal> computes <literal>X</literal>, solution
-            of the "discrete time" Sylvester equation
+            of the modified "discrete time" Sylvester equation
         </para>
         <programlisting role=""><![CDATA[
 A*X*B+X = C
  ]]></programlisting>
+        <para>
+            <literal>X=-sylv(-A, B, C, 'd')</literal> computes <literal>X</literal>, solution
+            of the real "discrete time" Sylvester equation
+        </para>
+        <programlisting role=""><![CDATA[
+A*X*B-X = C
+ ]]></programlisting>
     </refsection>
     <refsection>
         <title>Examples</title>
         <programlisting role="example"><![CDATA[
+// Continuous time Sylvester equation:
 A = rand(4, 4); C = rand(4, 3); B = rand(3, 3);
 X = sylv(A, B, C, 'c');
 norm(A*X+X*B-C)
+
+// Modified Discrete time Sylvester equation:
 X = sylv(A, B, C, 'd');
+norm(A*X*B+X-C)
+
+// Real Discrete time Sylvester equation:
+X = -sylv(-A, B, C, 'd');
 norm(A*X*B-X-C)
  ]]></programlisting>
     </refsection>