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Reorganize homepage.
author Kai T. Ohlhus <k.ohlhus@gmail.com>
date Thu, 10 Sep 2020 17:47:36 +0900
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1 ---
2 layout: page
3 title: GNU Octave Version 3
4 menu: false
5 permalink: NEWS-3.html
6 ---
7
8 ## Summary of important user-visible changes
9
10 December 21, 2007
11
12 {% include release_news_select.md %}
13
14 <ul>
15 <li>Compatibility with Matlab graphics is much better. We now
16 have some graphics features that work like Matlab's Handle
17 Graphics (tm):
18 <ul>
19 <li> You can make a subplot and then use the print function to
20 generate file with the plot.</li>
21
22 <li> RGB line colors are supported if you use gnuplot 4.2. Octave
23 can still use gnuplot 4.0, but there is no way to set arbitrary
24 line colors with it when using the Matlab-style plot functions.
25 There never was any way to do this reliably with older versions
26 of gnuplot (whether run from Octave or not) since it only
27 provided a limited set to choose from, and they were terminal
28 dependent, so choosing color 1 with the X11 terminal would be
29 different from color 1 with the PostScript terminal. Valid RGB
30 colors for gnuplot 4.0 are the eight possible combinations of 0
31 and 1 for the R, G and B values. Invalid values are all mapped
32 to the same color.
33 <p>
34 This also affects patch objects used in the bar, countour, meshc
35 and surfc functions, where the bars and contours will be
36 monochrome. A workaround for this is to type "colormap gmap40"
37 that loads a colormap that in many cases will be adequate for
38 simple bar and contour plots.</li>
39
40 <li> You can control the width of lines using (for example):
41 <pre>
42 line (x, y, "linewidth", 4, "color", [1, 0, 0.5]);
43 </pre>
44 (this also shows the color feature).</li>
45
46 <li> With gnuplot 4.2, image data is plotted with gnuplot and may be
47 combined with other 2-d plot data.</li>
48
49 <li> Lines for contour plots are generated with an Octave function, so
50 contour plots are now 2-d plots instead of special 3-d plots, and
51 this allows you to plot additional 2-d data on top of a contour
52 plot.</li>
53
54 <li> With the gnuplot "extended" terminals the TeX interpreter is
55 emulated. However, this means that the TeX interpreter is only
56 supported on the postscript terminals with gnuplot 4.0. Under
57 gnuplot 4.2 the terminals aqua, dumb, png, jpeg, gif, pm, windows,
58 wxt, svg and x11 are supported as well.</li>
59
60 <li> The following plot commands are now considered obsolete and will
61 be removed from a future version of Octave:
62 <pre>
63 __gnuplot_set__
64 __gnuplot_show__
65 __gnuplot_plot__
66 __gnuplot_splot__
67 __gnuplot_replot__
68 </pre>
69 Additionally, these functions no longer have any effect on plots
70 created with the Matlab-style plot commands
71 (<tt>plot</tt>, <tt>line</tt>, <tt>mesh</tt>, <tt>semilogx</tt>,
72 etc.).
73
74 <li> Plot property values are not extensively checked. Specifying
75 invalid property values may produce unpredictible results.</li>
76
77 <li> Octave now sends data over the same pipe that is used to send
78 commands to gnuplot. While this avoids the problem of
79 cluttering /tmp with data files, it is no longer possible to use
80 the mouse to zoom in on plots. This is a limitation of gnuplot,
81 which is unable to zoom when the data it plots is not stored in
82 a file. Some work has been done to fix this problem in newer
83 versions of gnuplot (> 4.2.2). See for example,
84 <a href="http://www.nabble.com/zooming-of-inline-data-tf4357017.html#a12416496">this thread</a> on the gnuplot development list.
85 </ul></li>
86
87
88 <li>The way Octave handles search paths has changed. Instead of
89 setting the built-in variable <tt>LOADPATH</tt>, you must
90 use <tt>addpath</tt>, <tt>rmpath</tt>, or <tt>path</tt> to
91 manipulate the function search path. These functions will
92 maintain <tt>"."</tt> at the head of the path, for compatibility
93 with Matlab.
94 <p>
95 Leading, trailing or doubled colons are no longer special.
96 Now, all elements of the search path are explicitly included in
97 the path when Octave starts. To display the path, use
98 the <tt>path</tt> function.
99 <p>
100 Path elements that end in <tt>//</tt> are no longer searched recursively.
101 Instead, you may use addpath and the genpath function to add an
102 entire directory tree to the path. For example,
103 <pre>
104 addpath (genpath ("~/octave"));
105 </pre>
106 will add ~/octave and all directories below it to the head of the
107 path.</li>
108
109
110 <li>Previous versions of Octave had a number of built-in variables to
111 control warnings (for example, <tt>warn_divide_by_zero</tt>). These
112 variables have been replaced by warning identifiers that are used
113 with the warning function to control the state of warnings.
114 <p>
115 For example, instead of writing
116 <pre>
117 warn_divide_by_zero = false;
118 </pre>
119 to disable divide-by-zero warnings, you should write
120 <pre>
121 warning ("off", "Octave:divide-by-zero");
122 </pre>
123 You may use the same technique in your own code to control
124 warnings. For example, you can use
125 <pre>
126 warning ("My-package:phase-of-the-moon",
127 "the phase of the moon could cause trouble today");
128 </pre>
129 to allow users to control this warning using the
130 <tt>"My-package:phase-of-the-moon"</tt> warning identifier.
131 <p>
132 You may also enable or disable all warnings, or turn them into
133 errors:
134 <pre>
135 warning ("on", "all");
136 warning ("off", "all");
137 warning ("error", "Octave:divide-by-zero");
138 warning ("error", "all");
139 </pre>
140 You can query the state of current warnings using
141 <pre>
142 warning ("query", ID)
143 warning ("query")
144 </pre>
145 (only those warning IDs which have been explicitly set are
146 returned).
147 <p>
148 A partial list and description of warning identifiers is available
149 using
150 <pre>
151 help warning_ids
152 </pre></li>
153
154
155 <li>All built-in variables have been converted to functions. This
156 change simplifies the interpreter and allows a consistent
157 interface to internal variables for user-defined packages and the
158 core functions distributed with Octave. In most cases, code that
159 simply accesses internal variables does not need to change. Code
160 that sets internal variables will change. For example, instead of
161 writing
162 <pre>
163 PS1 = ">> ";
164 </pre>
165 you will need to write
166 <pre>
167 PS1 (">> ");
168 </pre>
169 If you need write code that will run in both old and new versions
170 of Octave, you can use something like
171 <pre>
172 if (exist ("OCTAVE_VERSION") == 5)
173 ## New:
174 PS1 (">> ");
175 else
176 ## Old:
177 PS1 = ">> ";
178 endif
179 </pre></li>
180
181
182 <li>For compatibility with Matlab, the output order of Octave's
183 <tt>"system"</tt> function has changed from
184 <pre>
185 [output, status] = system (cmd);
186 </pre>
187 to
188 <pre>
189 [status, output] = system (cmd);
190 </pre></li>
191
192
193 <li>For compatibility with Matlab, <tt>normcdf</tt>, <tt>norminv</tt>,
194 <tt>normpdf</tt>, and <tt>normrnd</tt> have been modified to
195 compute distributions using the standard deviation instead of the
196 variance.</li>
197
198
199 <li>For compatibility with Matlab, the output of Octave's fsolve
200 function has been changed from
201 <pre>
202 [x, info, msg] = fsolve (...);
203 </pre>
204 to
205 <pre>
206 [x, fval, info] = fsolve (...);
207 </pre></li>
208
209
210 <li>For compatibility with Matlab, <tt>normcdf</tt>, <tt>norminv</tt>,
211 <tt>normpdf</tt>, and <tt>normrnd</tt> have been modified to
212 compute distributions using the standard deviation instead of the
213 variance.</li>
214
215
216 <li>For compatibility with
217 Matlab, <tt>gamcdf</tt>, <tt>gaminv</tt>, <tt>gampdf</tt>,
218 <tt>gamrnd</tt>, <tt>expcdf</tt>, <tt>expinv</tt>, <tt>exppdf</tt>
219 and <tt>exprnd</tt> have been modified to compute the
220 distributions using the standard scale factor rather than one over
221 the scale factor.
222 </ul>