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<h3 class="section">4.4 Integer Data Types</h3>
<p>Octave supports integer matrices as an alternative to using double
precision. It is possible to use both signed and unsigned integers
represented by 8, 16, 32, or 64 bits. It should be noted that most
computations require floating point data, meaning that integers will
often change type when involved in numeric computations. For this
reason integers are most often used to store data, and not for
calculations.
<p>In general most integer matrices are created by casting
existing matrices to integers. The following example shows how to cast
a matrix into 32 bit integers.
<pre class="example"> float = rand (2, 2)
⇒ float = 0.37569 0.92982
0.11962 0.50876
integer = int32 (float)
⇒ integer = 0 1
0 1
</pre>
<p class="noindent">As can be seen, floating point values are rounded to the nearest integer
when converted.
<!-- isinteger src/data.cc -->
<p><a name="doc_002disinteger"></a>
<div class="defun">
— Built-in Function: <b>isinteger</b> (<var>x</var>)<var><a name="index-isinteger-271"></a></var><br>
<blockquote><p>Return true if <var>x</var> is an integer object (int8, uint8, int16, etc.).
Note that <code>isinteger (14)</code><!-- /@w --> is false because numeric constants in
Octave are double precision floating point values.
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<p class="noindent"><strong>See also:</strong> <a href="doc_002disfloat.html#doc_002disfloat">isfloat</a>, <a href="doc_002dischar.html#doc_002dischar">ischar</a>, <a href="doc_002dislogical.html#doc_002dislogical">islogical</a>, <a href="doc_002disnumeric.html#doc_002disnumeric">isnumeric</a>, <a href="doc_002disa.html#doc_002disa">isa</a>.
</p></blockquote></div>
<!-- int8 src/ov-int8.cc -->
<p><a name="doc_002dint8"></a>
<div class="defun">
— Built-in Function: <b>int8</b> (<var>x</var>)<var><a name="index-int8-272"></a></var><br>
<blockquote><p>Convert <var>x</var> to 8-bit integer type.
</p></blockquote></div>
<!-- uint8 src/ov-uint8.cc -->
<p><a name="doc_002duint8"></a>
<div class="defun">
— Built-in Function: <b>uint8</b> (<var>x</var>)<var><a name="index-uint8-273"></a></var><br>
<blockquote><p>Convert <var>x</var> to unsigned 8-bit integer type.
</p></blockquote></div>
<!-- int16 src/ov-int16.cc -->
<p><a name="doc_002dint16"></a>
<div class="defun">
— Built-in Function: <b>int16</b> (<var>x</var>)<var><a name="index-int16-274"></a></var><br>
<blockquote><p>Convert <var>x</var> to 16-bit integer type.
</p></blockquote></div>
<!-- uint16 src/ov-uint16.cc -->
<p><a name="doc_002duint16"></a>
<div class="defun">
— Built-in Function: <b>uint16</b> (<var>x</var>)<var><a name="index-uint16-275"></a></var><br>
<blockquote><p>Convert <var>x</var> to unsigned 16-bit integer type.
</p></blockquote></div>
<!-- int32 src/ov-int32.cc -->
<p><a name="doc_002dint32"></a>
<div class="defun">
— Built-in Function: <b>int32</b> (<var>x</var>)<var><a name="index-int32-276"></a></var><br>
<blockquote><p>Convert <var>x</var> to 32-bit integer type.
</p></blockquote></div>
<!-- uint32 src/ov-uint32.cc -->
<p><a name="doc_002duint32"></a>
<div class="defun">
— Built-in Function: <b>uint32</b> (<var>x</var>)<var><a name="index-uint32-277"></a></var><br>
<blockquote><p>Convert <var>x</var> to unsigned 32-bit integer type.
</p></blockquote></div>
<!-- int64 src/ov-int64.cc -->
<p><a name="doc_002dint64"></a>
<div class="defun">
— Built-in Function: <b>int64</b> (<var>x</var>)<var><a name="index-int64-278"></a></var><br>
<blockquote><p>Convert <var>x</var> to 64-bit integer type.
</p></blockquote></div>
<!-- uint64 src/ov-uint64.cc -->
<p><a name="doc_002duint64"></a>
<div class="defun">
— Built-in Function: <b>uint64</b> (<var>x</var>)<var><a name="index-uint64-279"></a></var><br>
<blockquote><p>Convert <var>x</var> to unsigned 64-bit integer type.
</p></blockquote></div>
<!-- intmax src/bitfcns.cc -->
<p><a name="doc_002dintmax"></a>
<div class="defun">
— Built-in Function: <b>intmax</b> (<var>type</var>)<var><a name="index-intmax-280"></a></var><br>
<blockquote><p>Return the largest integer that can be represented in an integer type.
The variable <var>type</var> can be
<dl>
<dt><code>int8</code><dd>signed 8-bit integer.
<br><dt><code>int16</code><dd>signed 16-bit integer.
<br><dt><code>int32</code><dd>signed 32-bit integer.
<br><dt><code>int64</code><dd>signed 64-bit integer.
<br><dt><code>uint8</code><dd>unsigned 8-bit integer.
<br><dt><code>uint16</code><dd>unsigned 16-bit integer.
<br><dt><code>uint32</code><dd>unsigned 32-bit integer.
<br><dt><code>uint64</code><dd>unsigned 64-bit integer.
</dl>
<p>The default for <var>type</var> is <code>uint32</code>.
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<p class="noindent"><strong>See also:</strong> <a href="doc_002dintmin.html#doc_002dintmin">intmin</a>, <a href="doc_002dbitmax.html#doc_002dbitmax">bitmax</a>.
</p></blockquote></div>
<!-- intmin src/bitfcns.cc -->
<p><a name="doc_002dintmin"></a>
<div class="defun">
— Built-in Function: <b>intmin</b> (<var>type</var>)<var><a name="index-intmin-281"></a></var><br>
<blockquote><p>Return the smallest integer that can be represented in an integer type.
The variable <var>type</var> can be
<dl>
<dt><code>int8</code><dd>signed 8-bit integer.
<br><dt><code>int16</code><dd>signed 16-bit integer.
<br><dt><code>int32</code><dd>signed 32-bit integer.
<br><dt><code>int64</code><dd>signed 64-bit integer.
<br><dt><code>uint8</code><dd>unsigned 8-bit integer.
<br><dt><code>uint16</code><dd>unsigned 16-bit integer.
<br><dt><code>uint32</code><dd>unsigned 32-bit integer.
<br><dt><code>uint64</code><dd>unsigned 64-bit integer.
</dl>
<p>The default for <var>type</var> is <code>uint32</code>.
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<p class="noindent"><strong>See also:</strong> <a href="doc_002dintmax.html#doc_002dintmax">intmax</a>, <a href="doc_002dbitmax.html#doc_002dbitmax">bitmax</a>.
</p></blockquote></div>
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