<?xml version="1.0" encoding="UTF-8"?>

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 * pursuant to article 5.3.4 of the CeCILL v.2.1.
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 * For more information, see the COPYING file which you should have received
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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="ja" xml:id="inv">

    <refnamediv>

        <refname>inv</refname>

        <refpurpose>逆行列</refpurpose>

    </refnamediv>

    <refsynopsisdiv>

        <title>呼び出し手順</title>

        <synopsis>inv(X)</synopsis>

    </refsynopsisdiv>

    <refsection>

        <title>引数</title>

        <variablelist>

            <varlistentry>

                <term>X</term>

                <listitem>

                    <para>実数または複素数の正方行列, 多項式行列および

                        伝達関数または状態空間表現の有理行列.

                    </para>

                </listitem>

            </varlistentry>

        </variablelist>

    </refsection>

    <refsection>

        <title>説明</title>

        <para>

            <literal>inv(X)</literal> は,正方行列 <literal>X</literal>の逆行列

            となります.

            <literal>X</literal> のスケーリングが

            悪い場合や特異行列に近い場合には警告を出力します.

        </para>

        <para>

            多項式行列または伝達関数表現の有理行列の場合,

            <literal>inv(X)</literal> は <literal>invr(X)</literal>に等しくなります.

        </para>
        <para>
          <literal>inv([])</literal> returns <literal>[]</literal>.
        </para>

        <para>

            状態空間表現の線形システム(<literal>syslin</literal> リスト)の場合,

            <literal>invr(X)</literal> は <literal>invsyslin(X)</literal>に等しくなります.

        </para>

    </refsection>

    <refsection role="see also">

        <title>参照</title>

        <para>

            数値行列用の<literal>inv</literal> 関数は Lapack ルーチン

            DGETRF, DGETRI (実数行列の場合)および  ZGETRF, ZGETRI

            (複素数の場合)に基づいています.

            多項式および有理行列に関する <literal>inv</literal> は

            Scilab関数<literal>invr</literal>に基づいています.

        </para>

    </refsection>

    <refsection>

        <title>例</title>

        <programlisting role="example"><![CDATA[
A=rand(3,3);inv(A)*A
x=poly(0,'x');
A=[x,1,x;x^2,2,1+x;1,2,3];inv(A)*A
A=[1/x,2;2+x,2/(1+x)]
inv(A)*A
A=ssrand(2,2,3);
W=inv(A)*A
clean(ss2tf(W))
 ]]></programlisting>

    </refsection>

    <refsection>

        <title>参考</title>

        <simplelist type="inline">

            <member>

                <link linkend="slash">slash</link>

            </member>

            <member>

                <link linkend="backslash">backslash</link>

            </member>

            <member>

                <link linkend="pinv">pinv</link>

            </member>

            <member>

                <link linkend="qr">qr</link>

            </member>

            <member>

                <link linkend="lufact">lufact</link>

            </member>

            <member>

                <link linkend="lusolve">lusolve</link>

            </member>

            <member>

                <link linkend="invr">invr</link>

            </member>

            <member>

                <link linkend="coff">coff</link>

            </member>

            <member>

                <link linkend="coffg">coffg</link>

            </member>

        </simplelist>

    </refsection>

</refentry>

