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<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="stabil">
    <refnamediv>
        <refname>stabil</refname>
        <refpurpose>stabilization</refpurpose>
    </refnamediv>
    <refsynopsisdiv>
        <title>Syntax</title>
        <synopsis>
            F = stabil(A, B, alfa)
            K = stabil(Sys, alfa, beta)
        </synopsis>
    </refsynopsisdiv>
    <refsection>
        <title>Arguments</title>
        <variablelist>
            <varlistentry>
                <term>A</term>
                <listitem>
                    <para>
                        square real matrix (<literal>nx x nx</literal>)
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term>B</term>
                <listitem>
                    <para>
                        real matrix (<literal>nx x nu</literal>)
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term>alfa, beta</term>
                <listitem>
                    <para> real or complex vector (in conjugate pairs) or real number.</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term>F</term>
                <listitem>
                    <para>
                        real matrix (<literal>nx x nu</literal>)
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term>Sys</term>
                <listitem>
                    <para>
                        linear system (<literal>syslin</literal> list) (<literal>m</literal> inputs, <literal>p</literal> outputs).
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term>K</term>
                <listitem>
                    <para>
                        linear system (<literal>p</literal> inputs, <literal>m</literal> outputs)
                    </para>
                </listitem>
            </varlistentry>
        </variablelist>
    </refsection>
    <refsection>
        <title>Description</title>
        <para>
            <literal>F=stabil(A,B,alfa)</literal> returns a gain matrix <literal>F</literal> such that
            <literal>A+B*F</literal> is stable if pair <literal>(A,B)</literal> is stabilizable.
            Assignable poles are set to <literal>alfa(1),alfa(2),...</literal>.
            If <literal>(A,B)</literal> is not stabilizable a warning is given
            and assignable poles are set to <literal>alfa(1),alfa(2),...</literal>.
            If <literal>alfa</literal> is a number all eigenvalues are set to this
            <literal>alfa</literal> (default value is <literal>alfa=-1</literal>).
        </para>
        <para>
            <literal>K=stabil(Sys,alfa,beta)</literal> returns <literal>K</literal>, a compensator for <literal>Sys</literal>
            such that <literal>(A,B)</literal>-controllable eigenvalues are set to
            <literal>alfa</literal> and <literal>(C,A)</literal>-observable eigenvalues are set to <literal>beta</literal>.
        </para>
        <para>
            All assignable closed loop poles (which are given by the
            eigenvalues of <literal>Aclosed=h_cl(Sys,K)</literal> are set to <literal>alfa(i)</literal>'s
            and <literal>beta(j)</literal>'s.
        </para>
    </refsection>
    <refsection>
        <title>Examples</title>
        <programlisting role="example"><![CDATA[
// Gain:
Sys=ssrand(0,2,5,list('st',2,3,3));
A=Sys('A');B=Sys('B');F=stabil(A,B);
spec(A) //2 controllable modes 2 unstable uncontrollable modes
//and one stable uncontrollable mode
spec(A+B*F) //the two controllable modes are set to -1.
// Compensator:
Sys=ssrand(3,2,5,list('st',2,3,3)); //3 outputs, 2 inputs, 5 states
//2 controllables modes, 3 controllable or stabilizable modes.
K=stabil(Sys,-2,-3);  //Compensator for Sys.
spec(Sys('A'))
spec(h_cl(Sys,K))   //K Stabilizes what can be stabilized.
 ]]></programlisting>
    </refsection>
    <refsection role="see also">
        <title>See also</title>
        <simplelist type="inline">
            <member>
                <link linkend="st_ility">st_ility</link>
            </member>
            <member>
                <link linkend="contr">contr</link>
            </member>
            <member>
                <link linkend="ppol">ppol</link>
            </member>
        </simplelist>
    </refsection>
</refentry>
