File: general.htm

package info (click to toggle)
evolver 2.70+ds-4
  • links: PTS, VCS
  • area: main
  • in suites: bullseye, buster, sid
  • size: 17,148 kB
  • sloc: ansic: 127,395; makefile: 209; sh: 98
file content (339 lines) | stat: -rw-r--r-- 13,272 bytes parent folder | download | duplicates (2)
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
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
<!DOCTYPE HTML>
<head>
   <title>Surface Evolver Documentation</title>
<link rel="stylesheet" type="text/css" href="evdoc-style.css" />
<meta http-equiv="Content-Type" content="text/html;charset=utf-8" >
</head>
<body>
<a   id="miscellaneous-top"></a>

<h1 class="center"> 
<a href="http://www.susqu.edu/brakke/evolver/evolver.htm" class="comic">
Surface Evolver</a> Documentation</h1> 

<a href="evolver.htm#doc-top">Back to top of Surface Evolver documentation.</a>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
<a href="index.htm">Index.</a>

<h2> Some miscellaneous topics: </h2>
<ul>
<li><a href="#options">Command line options.</a>
<li><a href="#bugs">Bugs.</a>
<li><a href="#newsletters">Newsletters.</a>
<li><a href="#error-handling">Error handling.</a>
<li><a href="#initialization">Surface initialization.</a>
<li><a href="#interrupts">Interrupting execution.</a>
<li><a href="#parallel">Parallel computation.</a>
</ul>
<hr>

<a   id="options"></a>
<h2>Command line options</h2>

<p>The syntax for starting the Evolver from the system command prompt is:
</p>

<pre>
     evolver [-f<i>filename</i>] [-a-] [-d] [-e] [-i] [-m] [-p<i>n</i>] [-q] [-Q] [-w] [-x] [-y] [<em>datafile</em>]
</pre>

<p>The current directory and <a HREF="install.htm#EVOLVERPATH" 
  class="keyword">EVOLVERPATH</a>
will be searched for datafile. If the datafile is not found, then a new
search with extension <code>.fe</code> is done.
  Wildcard matching is in effect
on some systems (Windows, linux, maybe others), but be very careful when
using wildcards since there can be unexpected matches.
 If the datafile is still not found, or the
datafile is not given on the command line, then the user will be prompted.
Options: </p>

<dl>
<dt>
<a   id="no-autoconvert-option"></a>
<code> -a-</code>
</dt>
<dd>
Do not enable automatic conversion to 
<a href="quants.htm#named-methods">named methods</a> and 
<a href="quants.htm#named-quantities">quantities</a> mode when a
situation requiring it arises (for debugging).
<p></dd>
<dt>
<a   id="debug-option"></a>
<code>-d</code> </dt>

<dd>Prints YACC debugging trace as datafile is parsed. May be helpful if
you can't figure out why your datafile doesn't get read in properly AND
you know YACC. 
<p></dd>

<dt><a   id="echo-option"></a>
<code>-e</code></dt>
<dd>
 Echo input.  Meant for echoing commands of piped input to 
 screen so the user can follow what is going on in case Evolver is being
 controlled by another process.
<p></dd>

<dt><a   id="file-option"></a>
<code>-f</code><i>filename</i> </dt>

<dd>Specifies the name of a file to be used as command input after the
datafile is read. At the end of this file, input reverts to standard input.
The effect is the same as redirecting input from the file, except that
<code>-f</code> will echo commands to the screen and revert to standard input at the
end.  Also note that errors will cause input to revert to standard input.
<p></dd>

<dt><a   id="no-renumbering-option"></a>
<code>-i</code></dt>

<dd>  Keeps elements numbers as listed in the datafile, instead
   of renumbering them consecutively.  The same effect can be achieved
   by putting the keyword 
   <a href="datafile.htm" class="keyword">keep_originals</a> 
in the top of the datafile.
<p></dd>

<dt><a   id="memory-debug-option"></a>
<code>-m</code> </dt>

<dd>Turn memory debugging on at start of program. Same effect as Evolver
<a HREF="toggle.htm#memdebug" class="keyword">memdebug</a> toggle command. 
<p></dd>

<dt><a   id="multiprocessor-option"></a>
<code>-p</code><i>n</i> </dt>

<dd>Forces use of n processes for an Evolver compiled in multi-processor
mode. <i>n</i> may be larger or smaller than the physically available number of
processors. The default is 1.  This option should be regarded as experimental; 
there is still too much overhead for it to be useful usually.
<p></dd>

<dt><a   id="named-quantities-option"></a>
<code>-q</code> </dt>

<dd>Convert everything to <a HREF="quants.htm">named quantities</a> internally.
There are a few things for which no quantities exist yet; they will produce
error messages. 
<p></dd>

<dt><a   id="quietload-option"></a>
<code>-Q</code> </dt>

<dd>Suppresses echoing of <a href="datafile.htm#read-section" class="keyword">
read</a> section of datafile, and of
files input with the <a href="commands.htm" class="keyword">read</a> command; 
same as
<a href="toggle.htm#quietload" class="keyword">quietload</a> toggle.
<p></dd>

<dt>
<a   id="exit-warning-option"></a>
<code>-w</code> </dt>

<dd>Causes Evolver to exit whenever a warning occurs. Meant to be used when
Evolver is run in a shell script. 
<p></dd>

<dt><a   id="exit-error-option"></a>
<code>-x</code> </dt>

<dd>Causes Evolver to exit whenever an error occurs. Meant to be used when
Evolver is run in a shell script, so that Evolver doesn't get hung up waiting
for input in response to an error. 
<p></dd>

<dt><a   id="break-after-warning-option"></a>
<code>-y</code> </dt>

<dd>Causes Evolver to cease execution of commands and return to command
prompt after any warning message.  Same effect as 
<a href="toggle.htm#break_after_warning" class="keyword">break_after_warning</a> 
runtime toggle.
<p></dd>


</dl>

<p>
<hr><h2><a   id="bugs"></a>
Bugs</h2>
Bug reports should be submitted by email to <code>brakke@susqu.edu</code>.
Please include the Evolver version number, a description of the problem,
the initial data file, and the sequence of commands necessary to reproduce
the problem. 

<hr><h2><a   id="newsletters"></a>
Evolver Newsletters</h2>
The group of Surface Evolver users has grown large enough that I have
started a newsletter. Contents include announcement of new versions and
latest features, bibliography, and anything else anybody would like to
contribute. If you would like to be on the mailing list, send your email
address to <code>brakke@susqu.edu</code>. <p>

<p>Back issues: </p>

<ul>
<li><a HREF="news_01.htm">Newsletter 1</a> </li>
<li><a HREF="news_02.htm">Newsletter 2</a> </li>
<li><a HREF="news_03.htm">Newsletter 3</a> </li>
<li><a HREF="news_04.htm">Newsletter 4</a> </li>
<li><a HREF="news_05.htm">Newsletter 5</a> </li>
<li><a HREF="news_06.htm">Newsletter 6</a> </li>
<li><a HREF="news_07.htm">Newsletter 7</a> </li>
<li><a HREF="news_08.htm">Newsletter 8</a> </li>
<li><a HREF="news_09.htm">Newsletter 9</a> </li>
<li><a HREF="news_10.htm">Newsletter 10</a> </li>
<li><a HREF="news_11.htm">Newsletter 11</a> </li>
<li><a HREF="news_12.htm">Newsletter 12</a> </li>
<li><a HREF="news_13.htm">Newsletter 13</a> </li>
<li><a HREF="news_14.htm">Newsletter 14</a> </li>
<li><a HREF="news_15.htm">Newsletter 15</a> </li>
<li><a HREF="news_16.htm">Newsletter 16</a> </li>
<li><a HREF="news_17.htm">Newsletter 17</a> </li>
<li><a HREF="news_18.htm">Newsletter 18</a> </li>
<li><a HREF="news_19.htm">Newsletter 19</a> </li>
<li><a HREF="news_20.htm">Newsletter 20</a> </li>
<li><a HREF="news_21.htm">Newsletter 21</a> </li>
<li><a HREF="news_22.htm">Newsletter 22</a> </li>
</ul>

<p>
<hr><a   id="error-handling"></a><h2>Error handling</h2>
When the Surface Evolver detects an error, it prints an error message
and tries to take appropriate action. If the <a HREF="#options" 
class="keyword">-x</a>
command line option was given when Evolver was started, then Evolver exits
immediately with a nonzero error code. This is useful when running Evolver
from shell scripts. There are several categories of
errors: <p>

<ul>
<li><code>WARNING</code> - Something has happened that you should know about,
but Evolver proceeds normally after printing the message. By setting
the <code>break_after_warning</code> toggle, you can make Evolver then
cease execution at the end of the current command or subcommand.
By setting the <code>break_on_warning</code> toggle, you can make
Evolver return immediately to the command prompt.  The 
<code>-y</code> command-line option makes the Evolver exit after
 a warning, useful in batch runs. </li>

<li><code>SYNTAX ERROR</code> - The parser has detected an error. Recent input
up to the detection of the error is printed, but the actual problem may
be earlier.
</li>

<li><code>DATAFILE ERROR</code> - There is an error in the datafile being read
in. Evolver attempts to recover by skipping to the next recognizable part
of the datafile, but will abandon the datafile after 5 such errors. 
The surface data that was read in is available for your inspection,
but it probably forms an inconsistent surface and you should not try
to evolve it.</li>

<li><code>ERROR</code> - This is an error encountered during the execution
of a command. The command is abandoned and Evolver returns to the main
prompt.  The actions of the command are not undone.
The <code>-x</code> command line option makes Evolver exit immediately
after any error; useful batch runs. </li>

<li><code>FATAL ERROR</code> - An error from which recovery is impossible.
Evolver exits immediately. </li>
</ul>

<p>
<hr><a   id="initialization"></a>
<h2>
Surface initialization</h2>
Whenever the Surface Evolver loads a new surface, either on startup
or in response to the <a HREF="single.htm#q" class="keyword">q</a>
 or <a HREF="commands.htm#load" class="keyword">load</a>
commands, the following actions occur: <p>

<ul>
<li>Any previous surface has all memory deallocated. All user-defined variables
and commands are deleted, including any currently executing commands. </li>

<li>Internal variables are initialized to default values. </li>

<li>The datafile is read in. </li>

<li>In the <a HREF="model.htm#soapfilm-model">soapfilm model</a>, any nontriangular
face is divided into triangles by creating a vertex in the center and making
edges from the center to the vertices. </li>

<li>In the <a HREF="model.htm#soapfilm-model">soapfilm model</a>, the order
of facets around each edge is determined geometrically. </li>

<li>Vertices are projected to any <a HREF="constrnt.htm">level set constraints</a>.
</li>

<li>Checks as described for the <a HREF="single.htm#C">C</a> command are
done. </li>

<li>Initial areas, energies, and volumes are calculated. </li>

<li>The <a HREF="graphics.htm#view-matrix">viewing matrix</a> is reset
to center the object in the graphics window. </li>

<li>If any graphics are active, the new surface is drawn. </li>

<li>The main command prompt is started. </li>
</ul>

<p>
<hr><a   id="interrupts"></a><h2>Interrupting execution</h2>
Evolver operation may be interrupted with the standard keyboard interrupt,
CTRL-C usually (SIGINT for you unix gurus). During repeated operations,
this will set a flag which is checked at the end of each loop. Repetition
will cease after the current step and control will return to the main prompt.
If you give a second interrupt before the loop has ended, Evolver will
abort the command and return to the main prompt. Beware that this may leave
the surface in an inconsistent state if surface topology changing operations
were going on. An immediate abort will also happen if an interrupt is received
outside a loop. If Evolver receives SIGTERM (say from the unix kill command),
it will dump to the default 
<a href="commands.htm#dump">dump</a> file and exit. This is useful for stopping
a background Evolver running a script. The same thing will happen with
SIGHUP, so losing a modem connection will save the current surface. 
<p>
Note: In Microsoft Windows, the second interrupt doesn't do anything much
since Windows creates a separate thread to handle the interrupt, and
I can't find any way to force the offending thread to stop and longjmp
back to where it should.  So if the Evolver is really, really stuck,
you may just have to kill the whole program.

<hr><a   id="parallel"></a><h2>
Parallel computation</h2>
Parallel versions of the Surface Evolver are available for several
types of systems, but these are experimental and not very useful. <p>

For symmetric multiprocessors (several CPUs in the same machine), the
<code>-p</code><em>n</em> command line option will cause Evolver to use
<em>n</em> threads, so it is best if <em>n</em> does not exceed the
number of CPUs in the machine.
 It will slow things down to use more threads than are physically
available, but it is possible to run multiple threads on a single-processor
system for testing. 
<p>
 Currently, the only calculations done in parallel are the
 <a HREF="quants.htm">named quantities</a>, so it is best to start Evolver with the <a HREF="#options">-q</a>
option. 
 Evolver seems to be memory bandwidth limited, so
you may not get as much speed-up as you wish.
<p>
For distributed computation, there is an  <a HREF="MPI_evolver.htm">MPI 
version of Evolver</a>, but this is still experimental and not useful 
except in very special circumstances.
<hr>
<hr><a HREF="evolver.htm#doc-top">Back to top of Surface Evolver documentation.</a>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
<a href="index.htm">Index.</a>
<hr>
<a href="http://www.susqu.edu/facstaff/b/brakke/">
Author's home page.</a>

</body>
</html>