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
136
137
138
139
140
141
|
<!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: How can I handle memory limitations?</title>
<meta name="description" content="GNU Octave: How can I handle memory limitations?">
<meta name="keywords" content="GNU Octave: How can I handle memory limitations?">
<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="FAQ-_002d-Frequently-asked-Questions.html#FAQ-_002d-Frequently-asked-Questions" rel="up" title="FAQ - Frequently asked Questions">
<link href="Which-TeX-symbols-are-implemented-in-dialog-functions_003f.html#Which-TeX-symbols-are-implemented-in-dialog-functions_003f" rel="next" title="Which TeX symbols are implemented in dialog functions?">
<link href="How-to-create-an-instance-of-a-Java-class_003f.html#How-to-create-an-instance-of-a-Java-class_003f" rel="prev" title="How to create an instance of a Java class?">
<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="How-can-I-handle-memory-limitations_003f"></a>
<div class="header">
<p>
Next: <a href="Which-TeX-symbols-are-implemented-in-dialog-functions_003f.html#Which-TeX-symbols-are-implemented-in-dialog-functions_003f" accesskey="n" rel="next">Which TeX symbols are implemented in dialog functions?</a>, Previous: <a href="How-to-create-an-instance-of-a-Java-class_003f.html#How-to-create-an-instance-of-a-Java-class_003f" accesskey="p" rel="prev">How to create an instance of a Java class?</a>, Up: <a href="FAQ-_002d-Frequently-asked-Questions.html#FAQ-_002d-Frequently-asked-Questions" accesskey="u" rel="up">FAQ - Frequently asked Questions</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="How-can-I-handle-memory-limitations_003f-1"></a>
<h4 class="subsection">37.3.4 How can I handle memory limitations?</h4>
<a name="index-memory_002c-limitations"></a>
<p>In order to execute Java code Octave creates a Java Virtual Machine (JVM).
Such a JVM allocates a fixed amount of initial memory and may expand this pool
up to a fixed maximum memory limit. The default values depend on the Java
version (see <a href="Java-Interface-Functions.html#XREFjavamem">javamem</a>). The memory pool is shared by all
Java objects running in the JVM. This strict memory limit is intended mainly
to avoid that runaway applications inside web browsers or in enterprise servers
can consume all memory and crash the system. When the maximum memory limit is
hit, Java code will throw exceptions so that applications will fail or behave
unexpectedly.
</p>
<p>You can specify options for the creation of the JVM inside a file named
<samp>java.opts</samp>. This is a text file where you can enter lines containing
<samp>-X</samp> and <samp>-D</samp> options handed to the JVM during initialization.
</p>
<p>The directory where the Java options file is located is specified by the
environment variable <code><span class="nolinebreak">OCTAVE_JAVA_DIR</span></code><!-- /@w -->. If unset the directory where
<samp>javaclasspath.m</samp> resides is used instead (typically
<samp><code><span class="nolinebreak">OCTAVE_HOME</span></code><!-- /@w -->/share/octave/<code><span class="nolinebreak">OCTAVE_VERSION</span></code><!-- /@w -->/m/java/</samp>). You can
find this directory by executing
</p>
<div class="example">
<pre class="example">which javaclasspath
</pre></div>
<p>The <samp>-X</samp> options allow you to increase the maximum amount of memory
available to the JVM. The following example allows up to 256 Megabytes to
be used by adding the following line to the <samp>java.opts</samp> file:
</p>
<div class="example">
<pre class="example">-Xmx256m
</pre></div>
<p>The maximum possible amount of memory depends on your system. On a Windows
system with 2 Gigabytes main memory you should be able to set this maximum to
about 1 Gigabyte.
</p>
<p>If your application requires a large amount of memory from the beginning, you
can also specify the initial amount of memory allocated to the JVM. Adding
the following line to the <samp>java.opts</samp> file starts the JVM with 64
Megabytes of initial memory:
</p>
<div class="example">
<pre class="example">-Xms64m
</pre></div>
<p>For more details on the available <samp>-X</samp> options of your Java Virtual
Machine issue the command ‘<samp>java -X</samp>’ at the operating system command prompt
and consult the Java documentation.
</p>
<p>The <samp>-D</samp> options can be used to define system properties which can then
be used by Java classes inside Octave. System properties can be retrieved by
using the <code>getProperty()</code> methods of the <code>java.lang.System</code> class.
The following example line defines the property <var>MyProperty</var> and assigns it
the string <code>12.34</code>.
</p>
<div class="example">
<pre class="example">-DMyProperty=12.34
</pre></div>
<p>The value of this property can then be retrieved as a string by a Java object
or in Octave:
</p>
<div class="example">
<pre class="example">octave> javaMethod ("getProperty", "java.lang.System", "MyProperty");
ans = 12.34
</pre></div>
<p><strong>See also:</strong> javamem.
</p>
<hr>
<div class="header">
<p>
Next: <a href="Which-TeX-symbols-are-implemented-in-dialog-functions_003f.html#Which-TeX-symbols-are-implemented-in-dialog-functions_003f" accesskey="n" rel="next">Which TeX symbols are implemented in dialog functions?</a>, Previous: <a href="How-to-create-an-instance-of-a-Java-class_003f.html#How-to-create-an-instance-of-a-Java-class_003f" accesskey="p" rel="prev">How to create an instance of a Java class?</a>, Up: <a href="FAQ-_002d-Frequently-asked-Questions.html#FAQ-_002d-Frequently-asked-Questions" accesskey="u" rel="up">FAQ - Frequently asked Questions</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>
|
