<primary>erf</primary>
        </indexterm>
        <function>erf</function> ( <type>double precision</type> )
        <returnvalue>double precision</returnvalue>
       </para>
       <para>
        Error function
       </para>
       <para>
        <literal>erf(1.0)</literal>
        <returnvalue>0.8427007929497149</returnvalue>
       </para></entry>
      </row>

      <row>
       <entry role="func_table_entry"><para role="func_signature">
        <indexterm>
         <primary>erfc</primary>
        </indexterm>
        <function>erfc</function> ( <type>double precision</type> )
        <returnvalue>double precision</returnvalue>
       </para>
       <para>
        Complementary error function (<literal>1 - erf(x)</literal>, without
        loss of precision for large inputs)
       </para>
       <para>
        <literal>erfc(1.0)</literal>
        <returnvalue>0.15729920705028513</returnvalue>
       </para></entry>
      </row>

      <row>
       <entry role="func_table_entry"><para role="func_signature">
        <indexterm>
         <primary>exp</primary>
        </indexterm>
        <function>exp</function> ( <type>numeric</type> )
        <returnvalue>numeric</returnvalue>
       </para>
       <para role="func_signature">
        <function>exp</function> ( <type>double precision</type> )
        <returnvalue>double precision</returnvalue>
       </para>
       <para>
        Exponential (<literal>e</literal> raised to the given power)
       </para>
       <para>
        <literal>exp(1.0)</literal>
        <returnvalue>2.7182818284590452</returnvalue>
       </para></entry>
      </row>

      <row>
       <entry role="func_table_entry"><para role="func_signature">
        <indexterm id="function-factorial">
         <primary>factorial</primary>
        </indexterm>
        <function>factorial</function> ( <type>bigint</type> )
        <returnvalue>numeric</returnvalue>
       </para>
       <para>
        Factorial
       </para>
       <para>
        <literal>factorial(5)</literal>
        <returnvalue>120</returnvalue>
       </para></entry>
      </row>

      <row>
       <entry role="func_table_entry"><para role="func_signature">
        <indexterm>
         <primary>floor</primary>
        </indexterm>
        <function>floor</function> ( <type>numeric</type> )
        <returnvalue>numeric</returnvalue>
       </para>
       <para role="func_signature">
        <function>floor</function> ( <type>double precision</type> )
        <returnvalue>double precision</returnvalue>
       </para>
       <para>
        Nearest integer less than or equal to argument
       </para>
       <para>
        <literal>floor(42.8)</literal>
        <returnvalue>42</returnvalue>
       </para>
       <para>
        <literal>floor(-42.8)</literal>
        <returnvalue>-43</returnvalue>
       </para></entry>
      </row>

      <row>
       <entry role="func_table_entry"><para role="func_signature">
        <indexterm>
         <primary>gamma</primary>
        </indexterm>
        <function>gamma</function> ( <type>double precision</type> )
        <returnvalue>double precision</returnvalue>
       </para>
       <para>
        Gamma function
       </para>
       <para>
        <literal>gamma(0.5)</literal>
        <returnvalue>1.772453850905516</returnvalue>
       </para>
       <para>
        <literal>gamma(6)</literal>
        <returnvalue>120</returnvalue>
       </para></entry>
      </row>

      <row>
       <entry role="func_table_entry"><para role="func_signature">
        <indexterm>
         <primary>gcd</primary>
        </indexterm>
        <function>gcd</function> ( <replaceable>numeric_type</replaceable>, <replaceable>numeric_type</replaceable> )
        <returnvalue><replaceable>numeric_type</replaceable></returnvalue>
       </para>
       <para>
        Greatest common divisor (the largest positive number that divides both
        inputs with no remainder); returns <literal>0</literal> if both inputs