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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:ns5="http://www.w3.org/1999/xhtml" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:db="http://docbook.org/ns/docbook" xmlns:scilab="http://www.scilab.org" xml:id="isreal" xml:lang="ru">
    <refnamediv>
        <refname>isreal</refname>
        <refpurpose>проверка, имеет ли переменная вещественные или комплексные элементы</refpurpose>
    </refnamediv>
    <refsynopsisdiv>
        <title>Синтаксис</title>
        <synopsis>
            t = isreal(x)
            t = isreal(x, eps)
        </synopsis>
    </refsynopsisdiv>
    <refsection>
        <title>Аргументы</title>
        <variablelist>
            <varlistentry>
                <term>x</term>
                <listitem>
                    <para>Matrix of real or complex numbers (full or sparse storage).
                        Matrix of polynomials or rationals, with real or complex coefficients.
                    </para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term>eps</term>
                <listitem>
                    <para>положительный или нулевой реальный номер (по умолчанию = 0)</para>
                </listitem>
            </varlistentry>
            <varlistentry>
                <term>t</term>
                <listitem>
                    <para>логическое значение</para>
                </listitem>
            </varlistentry>
        </variablelist>
    </refsection>
    <refsection>
        <title>Описание</title>
        <para>
            <literal>isreal(x)</literal> возвращает значение "истина", если
            <literal>x</literal> хранится как вещественная переменная, и
            "ложь", если <literal>x</literal> имеет мнимую часть (даже если она нулевая).
        </para>
        <para>
            <literal>isreal(x,eps)</literal> возвращает "истину", если
            <literal>x</literal> хранится как вещественная переменная или если
            максимальное по модулю значение мнимой части меньше или равно
            <literal>eps</literal>.
        </para>
    </refsection>
    <refsection>
        <title>Примеры</title>
        <programlisting role="example"><![CDATA[
isreal([1 2])
isreal(1+0*%i)
isreal(1+0*%i,0)

// Sparse complex matrix:
isreal(sparse([1-%i -3+4*%i]))

// Complex polynomial:
p = (1-2*%s)^2
isreal(p)

// Complex rational fraction:
r = [ (%i-%s)/%s^2 %s/(2-%s)]
isreal(r)
]]></programlisting>
    </refsection>
    <refsection role="history">
        <title>История</title>
        <revhistory>
            <revision>
                <revnumber>6.0</revnumber>
                <revdescription>Extension to rationals
                </revdescription>
            </revision>
        </revhistory>
    </refsection>
</refentry>
