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<HTML>
<HEAD>
<TITLE>ROLL</TITLE>
</HEAD>
<BODY bgcolor="#FFFFFF" fgcolor="#000000">
<P><A NAME="roll"></A>
<font size="+3" color="green"><B>ROLL</B></font></P>
<P>
<TABLE border="1" cols="2" frame="box" rules="all" width="572">
<TR>
<TD width="15%" valign="top"><B>Syntax</B>:</TD>
<TD width="85%"><CODE>
vector = ROLL( vector, scalar )<br />
matrix = ROLL( matrix, scalar )</CODE>
</TD></TR>
</table></p>
<p>
The <CODE>ROLL</CODE> function accepts either a vector or a matrix
as its first argument. It shifts the elements of a vector or the rows of a matrix by the
specified step size, the scalar second argument.</p>
<P>
Suppose the step size is <i>n</i>.</P>
<P>
<table>
<tr>
<td valign="top">•</td><td>If <i>n</i> > 0, the last <i>n</i> elements of the vector
or the last <i>n</i> rows of the matrix are rolled around to the beginning.</td>
</tr><tr>
<td valign="top">•</td><td>If <i>n</i> = 0, the vector or matrix is returned unchanged.</td>
</tr><tr>
<td valign="top">•</td><td>If <i>n</i> < 0, the first <i>n</i> elements of the vector
or the first <i>n</i> rows of the matrix are rolled around to the end.</td>
</tr></table></P>
<P>
If the step size is not an integer, then linear interpolation is used to generate new
values.</P>
<P>
<font size="+1" color="green">Examples</font></P>
<P>
<table>
<tr>
<td bgcolor="#FFCCCC"><i>function</i></td><td bgcolor="#FFCCCC"><i>result</i></td>
</tr><tr>
<td><CODE><font color="blue">ROLL([1:10],2)</font></CODE></td>
<td bgcolor="#FFFFCC"><CODE>[9;10;1;2;3;4;5;6;7;8]</CODE></td>
</tr><tr>
<td><CODE><font color="blue">ROLL([1:10],-2)</font></CODE></td>
<td bgcolor="#FFFFCC"><CODE>[3;4;5;6;7;8;9;10;1;2]</CODE></td>
</tr><tr>
<td><CODE><font color="blue">ROLL([1:10],1.7)</font></CODE></td>
<td bgcolor="#FFFFCC"><CODE>[9.3;7.3;1.3;2.3;3.3;4.3;5.3;6.3;7.3;8.3]</CODE></td>
</tr></table></P>
<P>
Suppose you have a matrix <CODE>M</CODE><br />
<pre>
| 1 2 3 4 |
M = | 5 6 7 8 |
| 9 10 11 12 |
</pre></P>
<P>
<table>
<tr>
<td bgcolor="#FFCCCC"><i>function</i></td><td bgcolor="#FFCCCC"><center><i>result</i></center></td>
</tr><tr>
<td valign="middle"><CODE><font color="blue">ROLL(M,2)</font></CODE></td>
<td bgcolor="#FFFFCC"><table cellspacing="0"><tr><td><code>| 5 6 7 8 |</code></td></tr>
<tr><td><code>| 9 10 11 12 |</code></td></tr>
<tr><td><code>| 1 2 3 4 |</code></td></tr></table></td>
</tr><tr><td></td><td></td></tr><tr>
<td valign="middle"><CODE><font color="blue">ROLL(M,-1)</font></CODE></td>
<td bgcolor="#FFFFCC"><table cellspacing="0"><tr><td><CODE>| 5 6 7 8 |</CODE></td></tr>
<tr><td><CODE>| 9 10 11 12 |</CODE></td></tr>
<tr><td><CODE>| 1 2 3 4 |</CODE></td></tr></table></td>
</tr><tr><td></td><td></td></tr><tr>
<td valign="middle"><CODE><font color="blue">ROLL(M,1.5)</font></CODE></td>
<td bgcolor="#FFFFCC"><table cellspacing="0"><tr><td><CODE>| 7 8 9 10 |</CODE></td></tr>
<tr><td><CODE>| 5 6 7 8 |</CODE></td></tr>
<tr><td><CODE>| 3 4 5 6 |</CODE></td></tr></table></td>
</tr></table></P>
</BODY>
</HTML>
|
