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<div class="title">MINUS Subtraction Operator </div> </div>
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<div class="textblock"><p>Section: <a class="el" href="sec_operators.html">Mathematical Operators</a> </p>
<h1><a class="anchor" id="Usage"></a>
Usage</h1>
<p>Subtracts two numerical arrays (elementwise). There are two forms for its use, both with the same general syntax: </p>
<pre class="fragment"> y = a - b
</pre><p> where <code>a</code> and <code>b</code> are <code>n</code>-dimensional arrays of numerical type. In the first case, the two arguments are the same size, in which case, the output <code>y</code> is the same size as the inputs, and is the element-wise difference of <code>a</code> and <code>b</code>. In the second case, either <code>a</code> or <code>b</code> is a scalar, in which case <code>y</code> is the same size as the larger argument, and is the difference of the scalar to each element of the other argument.</p>
<p>The rules for manipulating types has changed in FreeMat 4.0. See <code>typerules</code> for more details.</p>
<h1><a class="anchor" id="Function"></a>
Internals</h1>
<p>There are three formulae for the subtraction operator, depending on the sizes of the three arguments. In the most general case, in which the two arguments are the same size, the output is computed via: </p>
<p class="formulaDsp">
<img class="formulaDsp" alt="\[ y(m_1,\ldots,m_d) = a(m_1,\ldots,m_d) - b(m_1,\ldots,m_d) \]" src="form_126.png"/>
</p>
<p> If <code>a</code> is a scalar, then the output is computed via </p>
<p class="formulaDsp">
<img class="formulaDsp" alt="\[ y(m_1,\ldots,m_d) = a - b(m_1,\ldots,m_d). \]" src="form_127.png"/>
</p>
<p> On the other hand, if <code>b</code> is a scalar, then the output is computed via </p>
<p class="formulaDsp">
<img class="formulaDsp" alt="\[ y(m_1,\ldots,m_d) = a(m_1,\ldots,m_d) - b. \]" src="form_128.png"/>
</p>
<h1><a class="anchor" id="Examples"></a>
Examples</h1>
<p>Here are some examples of using the subtraction operator. First, a straight-forward usage of the minus operator. The first example is straightforward:</p>
<pre class="fragment">--> 3 - 8
ans =
-5
</pre><p>Next, we subtract a vector of values from a scalar:</p>
<pre class="fragment">--> 3.1 - [2,4,5,6,7]
ans =
1.1000 -0.9000 -1.9000 -2.9000 -3.9000
</pre><p>With complex values</p>
<pre class="fragment">--> a = 3 - 4*i
a =
3.0000 - 4.0000i
--> b = a - 2
b =
1.0000 - 4.0000i
</pre><p>Finally, the element-wise version:</p>
<pre class="fragment">--> a = [1,2;3,4]
a =
1 2
3 4
--> b = [2,3;6,7]
b =
2 3
6 7
--> c = a - b
c =
-1 -1
-3 -3
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