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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" version="5.0-subset Scilab" xml:lang="en" xml:id="st_ility">
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<refname>st_ility</refname>
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<refpurpose> stabilizability test</refpurpose>
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<title>Calling Sequence</title>
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<synopsis>[ns, [nc, [,U [,Slo] ]]]=st_ility(Sl [,tol])</synopsis>
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<title>Arguments</title>
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<literal>syslin</literal> list (linear system)
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<para> integer (dimension of stabilizable subspace)</para>
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integer (dimension of controllable subspace <literal>nc <= ns</literal>)
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basis such that its <literal>ns</literal> (resp. <literal>nc</literal>) first components span the stabilizable (resp. controllable) subspace
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a linear system (<literal>syslin</literal> list)
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<para>threshold for controllability detection (see contr)</para>
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<title>Description</title>
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<literal> Slo=( U'*A*U, U'*B, C*U, D, U'*x0 )</literal> (<literal>syslin</literal> list)
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displays the stabilizable form of <literal>Sl</literal>. Stabilizability means
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<literal>ns=nx</literal> (dim. of <literal>A</literal> matrix).
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<programlisting role=""><![CDATA[
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<refname>st_ility</refname>
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<refpurpose> stabilizability test</refpurpose>
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<title>Calling Sequence</title>
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<synopsis>[ns, [nc, [,U [,Slo] ]]]=st_ility(Sl [,tol])</synopsis>
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<title>Arguments</title>
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<literal>syslin</literal> list (linear system)
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<para> integer (dimension of stabilizable subspace)</para>
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integer (dimension of controllable subspace <literal>nc <= ns</literal>)
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basis such that its <literal>ns</literal> (resp. <literal>nc</literal>) first components span the stabilizable (resp. controllable) subspace
59
a linear system (<literal>syslin</literal> list)
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<para>threshold for controllability detection (see contr)</para>
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<title>Description</title>
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<literal> Slo=( U'*A*U, U'*B, C*U, D, U'*x0 )</literal> (<literal>syslin</literal> list)
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displays the stabilizable form of <literal>Sl</literal>. Stabilizability means
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<literal>ns=nx</literal> (dim. of <literal>A</literal> matrix).
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<programlisting role=""><![CDATA[
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U'*A*U = [0,*,*] U'*B = [0]
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]]></programlisting>
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where <literal> (A11,B1) </literal> (dim(A11)= <literal>nc</literal>) is controllable and <literal>A22</literal>
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(dim(A22)=<literal>ns-nc</literal>) is stable.
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"Stable" means real part of eigenvalues negative for a continuous
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linear system, and magnitude of eigenvalues lower than one for a
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discrete-time system (as defined by <literal>syslin</literal>).
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<title>Examples</title>
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<programlisting role="example"><![CDATA[
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where <literal> (A11,B1) </literal> (dim(A11)= <literal>nc</literal>) is controllable and <literal>A22</literal>
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(dim(A22)=<literal>ns-nc</literal>) is stable.
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"Stable" means real part of eigenvalues negative for a continuous
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linear system, and magnitude of eigenvalues lower than one for a
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discrete-time system (as defined by <literal>syslin</literal>).
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<title>Examples</title>
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<programlisting role="example"><![CDATA[
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A=diag([0.9,-2,3]);B=[0;0;1];Sl=syslin('c',A,B,[]);
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[ns,nc,U]=st_ility(Sl);
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]]></programlisting>
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<refsection role="see also">
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<title>See Also</title>
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<simplelist type="inline">
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<link linkend="dt_ility">dt_ility</link>
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<link linkend="contr">contr</link>
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<link linkend="stabil">stabil</link>
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<link linkend="ssrand">ssrand</link>
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<refsection role="see also">
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<title>See Also</title>
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<simplelist type="inline">
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<link linkend="dt_ility">dt_ility</link>
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<link linkend="contr">contr</link>
113
<link linkend="stabil">stabil</link>
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<link linkend="ssrand">ssrand</link>