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<a name="NORM2-_002d_002d_002d-Euclidean-vector-norms"></a>
<h3 class="section">9.198 <code>NORM2</code> &mdash; Euclidean vector norms</h3>
<a name="index-NORM2"></a>
<a name="index-Euclidean-vector-norm"></a>
<a name="index-L2-vector-norm"></a>
<a name="index-norm_002c-Euclidean"></a>
<dl compact="compact">
<dt><em>Description</em>:</dt>
<dd><p>Calculates the Euclidean vector norm (<em>L_2</em> norm) of
of <var>ARRAY</var> along dimension <var>DIM</var>.
</p>
</dd>
<dt><em>Standard</em>:</dt>
<dd><p>Fortran 2008 and later
</p>
</dd>
<dt><em>Class</em>:</dt>
<dd><p>Transformational function
</p>
</dd>
<dt><em>Syntax</em>:</dt>
<dd><table>
<tr><td width="80%"><code>RESULT = NORM2(ARRAY[, DIM])</code></td></tr>
</table>
</dd>
<dt><em>Arguments</em>:</dt>
<dd><table>
<tr><td width="15%"><var>ARRAY</var></td><td width="70%">Shall be an array of type <code>REAL</code></td></tr>
<tr><td width="15%"><var>DIM</var></td><td width="70%">(Optional) shall be a scalar of type
<code>INTEGER</code> with a value in the range from 1 to n, where n
equals the rank of <var>ARRAY</var>.</td></tr>
</table>
</dd>
<dt><em>Return value</em>:</dt>
<dd><p>The result is of the same type as <var>ARRAY</var>.
</p>
<p>If <var>DIM</var> is absent, a scalar with the square root of the sum of all
elements in <var>ARRAY</var> squared is returned. Otherwise, an array of
rank <em>n-1</em>, where <em>n</em> equals the rank of <var>ARRAY</var>, and a
shape similar to that of <var>ARRAY</var> with dimension <var>DIM</var> dropped
is returned.
</p>
</dd>
<dt><em>Example</em>:</dt>
<dd><div class="smallexample">
<pre class="smallexample">PROGRAM test_sum
REAL :: x(5) = [ real :: 1, 2, 3, 4, 5 ]
print *, NORM2(x) ! = sqrt(55.) ~ 7.416
END PROGRAM
</pre></div>
</dd>
</dl>
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