1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
|
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<!-- Created by GNU Texinfo 5.2, http://www.gnu.org/software/texinfo/ -->
<head>
<title>GNU Octave: Test Plotting Functions</title>
<meta name="description" content="GNU Octave: Test Plotting Functions">
<meta name="keywords" content="GNU Octave: Test Plotting Functions">
<meta name="resource-type" content="document">
<meta name="distribution" content="global">
<meta name="Generator" content="makeinfo">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<link href="index.html#Top" rel="start" title="Top">
<link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index">
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
<link href="High_002dLevel-Plotting.html#High_002dLevel-Plotting" rel="up" title="High-Level Plotting">
<link href="Graphics-Data-Structures.html#Graphics-Data-Structures" rel="next" title="Graphics Data Structures">
<link href="Interacting-with-Plots.html#Interacting-with-Plots" rel="prev" title="Interacting with Plots">
<style type="text/css">
<!--
a.summary-letter {text-decoration: none}
blockquote.smallquotation {font-size: smaller}
div.display {margin-left: 3.2em}
div.example {margin-left: 3.2em}
div.indentedblock {margin-left: 3.2em}
div.lisp {margin-left: 3.2em}
div.smalldisplay {margin-left: 3.2em}
div.smallexample {margin-left: 3.2em}
div.smallindentedblock {margin-left: 3.2em; font-size: smaller}
div.smalllisp {margin-left: 3.2em}
kbd {font-style:oblique}
pre.display {font-family: inherit}
pre.format {font-family: inherit}
pre.menu-comment {font-family: serif}
pre.menu-preformatted {font-family: serif}
pre.smalldisplay {font-family: inherit; font-size: smaller}
pre.smallexample {font-size: smaller}
pre.smallformat {font-family: inherit; font-size: smaller}
pre.smalllisp {font-size: smaller}
span.nocodebreak {white-space:nowrap}
span.nolinebreak {white-space:nowrap}
span.roman {font-family:serif; font-weight:normal}
span.sansserif {font-family:sans-serif; font-weight:normal}
ul.no-bullet {list-style: none}
-->
</style>
</head>
<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000">
<a name="Test-Plotting-Functions"></a>
<div class="header">
<p>
Previous: <a href="Interacting-with-Plots.html#Interacting-with-Plots" accesskey="p" rel="prev">Interacting with Plots</a>, Up: <a href="High_002dLevel-Plotting.html#High_002dLevel-Plotting" accesskey="u" rel="up">High-Level Plotting</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
</div>
<hr>
<a name="Test-Plotting-Functions-1"></a>
<h4 class="subsection">15.2.10 Test Plotting Functions</h4>
<p>The functions <code>sombrero</code> and <code>peaks</code> provide a way to check
that plotting is working. Typing either <code>sombrero</code> or <code>peaks</code>
at the Octave prompt should display a three-dimensional plot.
</p>
<a name="XREFsombrero"></a><dl>
<dt><a name="index-sombrero"></a>Function File: <em></em> <strong>sombrero</strong> <em>()</em></dt>
<dt><a name="index-sombrero-1"></a>Function File: <em></em> <strong>sombrero</strong> <em>(<var>n</var>)</em></dt>
<dt><a name="index-sombrero-2"></a>Function File: <em><var>z</var> =</em> <strong>sombrero</strong> <em>(…)</em></dt>
<dt><a name="index-sombrero-3"></a>Function File: <em>[<var>x</var>, <var>y</var>, <var>z</var>] =</em> <strong>sombrero</strong> <em>(…)</em></dt>
<dd><p>Plot the familiar 3-D sombrero function.
</p>
<p>The function plotted is
</p>
<div class="example">
<pre class="example">z = sin (sqrt (x^2 + y^2)) / (sqrt (x^2 + y^2))
</pre></div>
<p>Called without a return argument, <code>sombrero</code> plots the surface of the
above function over the meshgrid [-8,8] using <code>surf</code>.
</p>
<p>If <var>n</var> is a scalar the plot is made with <var>n</var> grid lines.
The default value for <var>n</var> is 41.
</p>
<p>When called with output arguments, return the data for the function
evaluated over the meshgrid. This can subsequently be plotted with
<code>surf (<var>x</var>, <var>y</var>, <var>z</var>)</code>.
</p>
<p><strong>See also:</strong> <a href="#XREFpeaks">peaks</a>, <a href="Three_002dDimensional-Plots.html#XREFmeshgrid">meshgrid</a>, <a href="Three_002dDimensional-Plots.html#XREFmesh">mesh</a>, <a href="Three_002dDimensional-Plots.html#XREFsurf">surf</a>.
</p></dd></dl>
<a name="XREFpeaks"></a><dl>
<dt><a name="index-peaks"></a>Function File: <em></em> <strong>peaks</strong> <em>()</em></dt>
<dt><a name="index-peaks-1"></a>Function File: <em></em> <strong>peaks</strong> <em>(<var>n</var>)</em></dt>
<dt><a name="index-peaks-2"></a>Function File: <em></em> <strong>peaks</strong> <em>(<var>x</var>, <var>y</var>)</em></dt>
<dt><a name="index-peaks-3"></a>Function File: <em><var>z</var> =</em> <strong>peaks</strong> <em>(…)</em></dt>
<dt><a name="index-peaks-4"></a>Function File: <em>[<var>x</var>, <var>y</var>, <var>z</var>] =</em> <strong>peaks</strong> <em>(…)</em></dt>
<dd><p>Plot a function with lots of local maxima and minima.
</p>
<p>The function has the form
</p>
<pre class="verbatim">f(x,y) = 3*(1-x)^2*exp(-x^2 - (y+1)^2) ...
- 10*(x/5 - x^3 - y^5)*exp(-x^2-y^2) ...
- 1/3*exp(-(x+1)^2 - y^2)
</pre>
<p>Called without a return argument, <code>peaks</code> plots the surface of the
above function using <code>surf</code>.
</p>
<p>If <var>n</var> is a scalar, <code>peaks</code> plots the value of the above
function on an <var>n</var>-by-<var>n</var> mesh over the range [-3,3]. The
default value for <var>n</var> is 49.
</p>
<p>If <var>n</var> is a vector, then it represents the grid values over which
to calculate the function. If <var>x</var> and <var>y</var> are specified then
the function value is calculated over the specified grid of vertices.
</p>
<p>When called with output arguments, return the data for the function
evaluated over the meshgrid. This can subsequently be plotted with
<code>surf (<var>x</var>, <var>y</var>, <var>z</var>)</code>.
</p>
<p><strong>See also:</strong> <a href="#XREFsombrero">sombrero</a>, <a href="Three_002dDimensional-Plots.html#XREFmeshgrid">meshgrid</a>, <a href="Three_002dDimensional-Plots.html#XREFmesh">mesh</a>, <a href="Three_002dDimensional-Plots.html#XREFsurf">surf</a>.
</p></dd></dl>
<hr>
<div class="header">
<p>
Previous: <a href="Interacting-with-Plots.html#Interacting-with-Plots" accesskey="p" rel="prev">Interacting with Plots</a>, Up: <a href="High_002dLevel-Plotting.html#High_002dLevel-Plotting" accesskey="u" rel="up">High-Level Plotting</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
</div>
</body>
</html>
|
