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
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
|
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html
PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>CarpetCode</title>
</head>
<body>
<h1 align="center">CarpetCode</h1>
<table>
<tr>
<td valign="top" bgcolor="#ffcc77" width="1%">
<p><b>CarpetCode</b><br />
<a href="http://www.carpetcode.org/">home page</a></p>
<p><b>Documentation</b><br />
<a href="doc/documentation.pdf">Introduction</a> (PDF, 210 kB)<br />
<a href="doc/first-steps.pdf">First Steps</a> (PDF, 130 kB)<br />
<a href="doc/internals.pdf">Internals</a> (PDF, 120 kB)<br />
<a href="doc/scheduling.pdf">Scheduling</a> (PDF, 120 kB)<br />
<a href="humour.html">Other Carpets</a></p>
<p><b>Mailing Lists</b><br />
<a href="http://lists.carpetcode.org/listinfo/developers/">Subscribe</a><br />
<a href="http://lists.carpetcode.org/archives/developers/">List Archive</a><br />
<a href="http://lists.carpetcode.org/listinfo/carpet-cvs/">CVS messages</a><br />
<a href="http://lists.carpetcode.org/listinfo/carpet-darcs/">darcs/git messages</a></p>
<p><b>Development</b><br />
<a href="get-carpet.html">Download</a><br />
<a href="http://bugs.carpetcode.org/">Bug Reports</a><br />
<a href="contributors.html">Contributors</a></p>
<!-- These are outdated
<a href="feature-requests.html">Missing features</a><br />
<a href="status-reports.html">Status reports</a><br />
-->
<p><b>Visualisation</b><br />
<a href="visualisation-tools.html">Tools</a><br />
<a href="https://mailserv.aei.mpg.de/mailman/listinfo/visualization/">Mailing List</a></p>
<p><b>Results</b><br />
<a href="publications.html">Publications</a></p>
<p><b>Related</b><br />
<a href="http://www.cactuscode.org/">Cactus</a><br />
<a href="http://relativity.phys.lsu.edu/">LSU Relativity Group</a><br />
<a href="http://www.cct.lsu.edu/numerical/">numrel@CCT</a><br />
<a href="http://numrel.aei.mpg.de/">numrel@aei</a><br />
<a href="http://www.whiskycode.org/">Whisky</a><br />
<a href="http://relativity.phys.lsu.edu/postdocs/matt/taka.php">Taka</a><br />
<a href="http://sbir.nasa.gov/SBIR/abstracts/05/sttr/phase1/STTR-05-1-T4.02-9864.html?solicitationId=STTR_05_P1">parca</a></p>
<p><b>Carpet Users</b><br />
<a href="http://numrel.aei.mpg.de/">AEI Potsdam</a><br />
<a href="http://www.as.arizona.edu/">University of Arizona</a><br />
<!-- <a href="http://www.astro.auth.gr/Science-Subjects/Gravity.html">AUTH</a><br /> -->
<a href="http://ww2.tpi.uni-jena.de/gravity/">Jena</a><br />
<a href="http://www.kisti.re.kr/english/">KISTI</a><br />
<a href="http://www.cct.lsu.edu/">LSU</a><br />
<!-- <a href="http://www.mpa-garching.mpg.de/hydro/index.shtml">MPA Garching</a><br /> -->
<a href="http://www.fis.unipr.it/numrel/">Parma</a><br />
<a href="http://www.gravity.psu.edu/numrel/">Penn State</a><br />
<a href="http://astrophysics.rit.edu/">RIT</a><br />
<a href="http://www.sissa.it/ap/RelAstro/">SISSA</a><br />
<a href="http://www.maths.soton.ac.uk/applied/relativity/">Southampton</a><br />
<a href="http://www.tat.physik.uni-tuebingen.de/">TAT/CPT</a><br />
<a href="http://www2.polito.it/ricerca/relgrav/">Torino</a><br />
<a href="http://research.physics.uiuc.edu/CTA/IRG/">UIUC</a><br />
<a href="http://www.nuclecu.unam.mx/~gravit/Gravit/">UNAM</a><br />
<!-- <a href="http://cgwa.phys.utb.edu/">UTB</a><br /> -->
<a href="http://wugrav.wustl.edu/">WashU</a></p>
<p><b>Feedback</b><br />
<a href="mailto:schnetter@carpetcode.org">Send email</a></p>
</td>
<td valign="top">
<p>Carpet is an adaptive mesh refinement driver for
the <a href="http://www.cactuscode.org/">Cactus Framework</a>.
Cactus is a software framework for solving time-dependent partial
differential equations on block-structured grids, and Carpet acts
as <i>driver layer</i> providing adaptive mesh refinement,
multi-patch capability, as well as parallelisation and efficient
I/O.</p>
<p>Carpet was created in 2001
by <a href="http://www.cct.lsu.edu/~eschnett/">Erik Schnetter</a>
at the <a href="http://www.tat.physik.uni-tuebingen.de/">TAT</a>
(Theoretische Astrophysik Tübingen) and subsequently brought into
production use by Erik Schnetter, Scott Hawley, and Ian Hawke at
the <a href="http://www.aei.mpg.de/">AEI</a> (Max-Planck-Institut
für Gravitationsphysik, Albert-Einstein-Institut). Carpet is
currently maintained at
the <a href="http://www.cct.lsu.edu/">CCT</a> (Center for
Computation & Technology)
at <a href="http://www.lsu.edu/">LSU</a>. These pages describe
Carpet and its current development.</p>
<hr />
<h2>News</h2>
<table><tr><td valign="top">
<p><b>March 1, 2008:</b> Carpet has a logo! This logo is
a <a href="http://en.wikipedia.org/wiki/Sierpinski_carpet">Sierpiński
carpet</a>, which is a fractal pattern with
a <a href="http://en.wikipedia.org/wiki/Hausdorff_dimension">Hausdorff
dimension</a> of 1.89279.</p>
</td><td valign="top">
<p><a href="logo/Sierpinski.pdf"><img src="logo/Sierpinski.png"
width="100" alt="Carpet logo (a Sierpiński
carpet)"/></a></p>
</td></tr></table>
<p><b>March 1, 2008:</b> We have improved the development version
of Carpet significantly:<br /></p>
<ul>
<li><p>The data structures and algorithms storing and handling
the communication schedule are much more efficient on large
numbers (several hundred or more) processors. This makes Carpet
scale to more than 8,000 cores.</p></li>
<li><p>The interface for defining and making dynamic changes to
grid hierarchies is simpler, and buffer zones are handled in a
cleaner manner. This makes it easier to write user code which
defines or updates the grid hierarchy, and reduces the chance of
inconsistencies therein.</p></li>
<li><p>During checkpointing and recovery, the grid structure is
saved and restored by default. This avoids accidental changes
upon recovery.</p></li>
<li><p>The efficiency of I/O has been increased, especially for
HDF5 based binary I/O. It is possible to combine several
variables into one file to reduce the number of output
files.</p></li>
<li><p>A new thorn LoopControl offers iterators over grid
points, implemented as C-style macros. These iterators allow
additional important loop-level optimisations, such
as <a href="http://en.wikipedia.org/wiki/Loop_tiling">loop
tiling</a> or
<a href="http://www.openmp.org/">OpenMP</a> parallelisation.
Efficient cache handling and hybrid communication models have a
large potential for performance improvements on current and
future architectures.</p></li>
</ul>
<p>More details can be found <a href="version-4.html">here</a>.
These improvements are largely due
to <a href="http://www.cct.lsu.edu/~eschnett/">Erik Schnetter</a>
(LSU),
<a href="http://www.aei.mpg.de/~tradke/">Thomas Radke</a> (AEI), and
<a href="http://proteus.as.arizona.edu/~cott">Christian D. Ott</a>
(UA). Special thanks go to Christian Reisswig and Luca
Baiotti.</p>
<p><b>March 1, 2008:</b> The development version of Carpet is now
maintained using <a href="http://git.or.cz/">git</a> instead
of <a href="http://www.darcs.net/">darcs</a>. Git offers a very
similar set of features to darcs, most importantly supporting
decentralised development. Git has a much larger user community
than darcs, and we hope that this makes it easier to use.
The <a href="get-carpet.html">download instructions</a> contain
details on using git to obtain Carpet, and point to further
information. (The darcs repository for the development version
will not see any further changes.)</p>
<p><b>March 1, 2008:</b> The repository for the development
version of Carpet moved today to
a <a href="http://carpetcode.dyndns.org/">new server</a>. The
stable versions of Carpet continue to be served from the old
server for the time being. We plan to move all of carpetcode.org
to this new server in the future. The new server is a courtesy
of <a href="http://proteus.as.arizona.edu/~cott">Christian
D. Ott</a>.</p>
<table><tr><td valign="top">
<p><b>January 14, 2008:</b> Carpet's communication
infrastructure has been improved significantly, making Carpet
scale to at least 4,000 processors, including mesh refinement.
Using "friendly user time"
on <a
href="http://www.tacc.utexas.edu/services/userguides/ranger/">Ranger</a>,
the new 60,000
core <a href="http://www.teragrid.org/">TeraGrid</a>
supercomputer
at <a href="http://www.tacc.utexas.edu/">TACC</a>, we measured
the benchmark results below for a numerical relativity kernel
solving the BSSN equations. These benchmarks emply a hybrid
communication scheme
combining <a href="http://www-unix.mcs.anl.gov/mpi/">MPI</a>
and
<a href="http://www.openmp.org/">OpenMP</a>, using the shared
memory capabilities of Ranger's nodes to reduce the memory
overhead of parallelisation. We are grateful for the help we
received from Ranger's support team.</p>
<p>The graph below shows weak scaling tests for both unigrid and
mesh refinement benchmarks. The problem size per core was
kept fixed, and there were 4 OpenMP threads per MPI process,
with 1 MPI process per socket. The benchmark was also run
with the PUGH driver for comparison for certain core counts.
As the graphs show, this benchmark scales near perfectly for
unigrid, and has only small variations in run time for nine
levels of mesh refinement.</p>
</td><td valign="top">
<p><a
href="scaling-ranger/results-ranger.pdf"><img
src="scaling-ranger/results-ranger.png" width="200"
alt="Scaling graph for Ranger"/></a></p>
</td></tr></table>
<!--
<p><b>October 4, 2007:</b> Announcement: <i>The BBH factory</i><br />
<b>Physicist version:</b> The BBH factory is a glorified set of shell
scripts which help maintaining source code on different machines
and building Cactus executables there. They also simplify the
task of managing many simulations on many machines and try to
prevent stupid errors.<br />
<b>Computer scientist version:</b> The BBH factory is a set of
abstractions over the various low-level interface that current
supercomputers offer for maintaining source code and performing
simulations. As middleware, they encompass policies and best
practices that prevent common human errors. They would also be
well suited for implementing graphical user interfaces.</p>
-->
<p><b>October 3, 2007:</b> Carpet's timing infrastructure has been
extended to automatically measure both time spent computing and
time spent in I/O. The performance of large simulations depends
not only on the computational efficiency and communication
latency, but also on the throughput to file servers. These new
statistics give a real-time overview and can point out
performance problems. The statistics are collected in the
existing <tt>Carpet::timing</tt> variables.</p>
<p><b>August 30, 2007:</b> So far this year, ten of the
publications from three research groups examining the dynamics
of binary black hole systems are based on simulations performed
with Cactus and Carpet:<br />
<a href="http://www.journals.uchicago.edu/ApJ/journal/issues/ApJ/v661n1/71342/71342.html">Astrophys. J. <b>661</b>, 430-436 (2007)</a>
(<a href="http://arxiv.org/abs/gr-qc/0701143">arXiv:gr-qc/0701143</a>)<br />
<a href="http://link.aps.org/abstract/PRL/v99/e041102">Phys. Rev. Lett. <b>99</b>, 041102 (2007)</a>
(<a href="http://arxiv.org/abs/gr-qc/0701163">arXiv:gr-qc/0701163</a>)<br />
<a href="http://www.journals.uchicago.edu/ApJ/journal/issues/ApJL/v659n1/21515/brief/21515.abstract.html">Astrophys. J. <b>659</b>, L5-L8 (2007)</a>
(<a href="http://arxiv.org/abs/gr-qc/0701164">arXiv:gr-qc/0701164</a>)<br />
<a href="http://link.aps.org/abstract/PRL/v98/e231102">Phys. Rev. Lett. <b>98</b>, 231102 (2007)</a>
(<a href="http://arxiv.org/abs/gr-qc/0702133">arXiv:gr-qc/0702133</a>)<br />
<a href="http://www.iop.org/EJ/abstract/0264-9381/24/15/009/">Class. Quantum Grav. <b>24</b>, 3911-3918 (2007)</a>
(<a href="http://arxiv.org/abs/gr-qc/0701038">arXiv:gr-qc/0701038</a>)<br />
<a href="http://arxiv.org/abs/0705.3829">arXiv:0705.3829 [gr-qc]</a><br />
<a href="http://arxiv.org/abs/0706.2541">arXiv:0706.2541 [gr-qc]</a><br />
<a href="http://arxiv.org/abs/0707.2559">arXiv:0707.2559 [gr-qc]</a><br />
<a href="http://arxiv.org/abs/0708.3999">arXiv:0708.3999 [gr-qc]</a><br />
<a href="http://arxiv.org/abs/0708.4048">arXiv:0708.4048 [gr-qc]</a><br />
These publications mainly examine the spin dynamics and the
gravitational wave recoil in BBH systems. Since not all
research groups use Cactus and Carpet, this represents only part
of the published work on this subject.</p>
<table><tr><td valign="top">
<p><b>August 26, 2007:</b> In experiments with hybrid
communication schemes
combining <a href="http://www-unix.mcs.anl.gov/mpi/">MPI</a>
and
<a href="http://www.openmp.org/">OpenMP</a>, we found a 20%
speed improvement when using a single node
of <a
href="http://www.ncsa.uiuc.edu/UserInfo/Resources/Hardware/Intel64Cluster/">Abe</a>
at <a href="http://www.ncsa.uiuc.edu">NCSA</a>, and a
substantial scaling improvement when using 1024 and more CPUs.
(Abe has 8 CPUs per node.) These experiments included cache
optimisations when traversing the 3D arrays. The tests were
performed with a modified version of
the <a
href="http://www.cactuscode.org/">Cactus</a> <a
href="http://www.cactuscode.org/WaveToyDemo/">WaveToy</a>
example application without using I/O or analysis methods.</p>
</td><td valign="top">
<p><a
href="hybrid-scaling/results-wavetoy-abe.pdf"><img
src="hybrid-scaling/results-wavetoy-abe.png" width="200"
alt="Scaling graph for Abe"/></a></p>
</td></tr></table>
<p><b>August 15, 2007:</b> We are happy to hear that our
proposal <i>ALPACA: Cactus tools for Application Level Profiling
And Correctness Analysis</i> will be funded by
<a
href="http://www.nsf.gov/">NSF's</a> <a
href="http://www.nsf.gov/publications/pub_summ.jsp?ods_key=nsf07503">SDCI</a>
programme for three years.
The <a
href="http://www.cactuscode.org/Development/alpaca">ALPACA</a>
project is aiming at developing complex, collaborative
scientific applications, appropriate for highly scalable
hardware architectures, providing fault tolerance, advanced
debugging, and transparency against new developments in
communication, programming, and execution models. Such tools
are especially rare at the application level, where they are
most critically needed.</p>
<p><b>July 31, 2007:</b> We are happy to hear that our
proposal <i>XiRel: Cyberinfrastructure for Numerical
Relativity</i> will be funded by
<a href="http://www.nsf.gov/">NSF's</a> <a href="http://www.nsf.gov/funding/pgm_summ.jsp?pims_id=6681">PIF</a>
programme for three
years. <a href="http://www.cct.lsu.edu/xirel/">XiRel</a> is
collaborative proposal
by <a href="http://www.cct.lsu.edu/">LSU</a>, <a href="http://gravity.psu.edu/numrel/">PSU</a>,
and <a href="http://www.phys.utb.edu/numrel/">UTB</a>
(now <a href="http://ccrg.rit.edu/">RIT</a>). The central goal of
XiRel is the development of a highly scalable, efficient, and
accurate adaptive mesh refinement layer based on the current
Carpet driver, which will be fully integrated and supported in
Cactus and optimised for numerical relativity.</p>
<p><a href="olds.html"><b>Old News...</b></a></p>
<hr />
<h2>Documentation</h2>
<p>We have accumulated a few pieces of documentation:</p>
<ul>
<li>An <a href="doc/documentation.pdf">introduction</a>
(PDF, 210 kB) to Carpet, as well as a guide to the
first steps for using it. Everybody should have read this.
(This is the same as the Arrangement Guide from the Carpet
sources.)</li>
<li><a
href="http://www.gravity.psu.edu/numrel/people/sperhake_ulrich.html">Ulrich
Sperhake</a> wrote a tutorial outlining the <a
href="doc/first-steps.pdf">first steps</a> (PDF, 130 kB)
that one has to take to install Carpet and run an example
application.</li>
<li>An explanation of the <a href="doc/internals.pdf">internal
workings</a> (PDF, 120 kB) of Carpet. You should read
this if you want to modify Carpet.</li>
<li>An explanation of
<a href="doc/scheduling.pdf">how scheduling works</a>
(PDF, 120 kB) in (PUGH and) Carpet. This may be
useful for setting up mixtures of local and global operations.</li>
<li>The individual Thorn Guides of Carpet. They are available
with the source code. They give details about the thorns' APIs
and user interfaces.</li>
<li>Thanks to <a
href="http://www.stack.nl/~dimitri/doxygen/">Doxygen</a>, we now
have an <a href="doxygen/html/index.html">overview</a> over all
the routines and data structures in Carpet. Most individual
Doxygen tags are still missing, but the extracted documentation
is already very useful. (The online documentation might not
always be up to date; in case of doubt, extract the
documentation yourself.)</li>
</ul>
<hr />
<h2>Interacting with the developers</h2>
<p>Most discussions about Carpet, i.e. user questions, feature
requests, and bug reports, are held on the Carpet developers'
mailing list <a
href="mailto:developers@lists.carpetcode.org">developers@lists.carpetcode.org</a>.
You can subscribe and unsubscribe from our <a
href="http://lists.carpetcode.org/">list management web page</a>.
You will also find the mailing list archive there. We thank <a
href="http://www.tat.physik.uni-tuebingen.de/~kobras/">Daniel
Kobras</a> for managing the mailing list server.</p>
<p>We have started to use <a
href="http://www.bugzilla.org/">Bugzilla</a> to keep track of
requested features or reported bugs in Carpet. You can submit or
comment on issues from our <a
href="http://bugs.carpetcode.org/">Bugzilla pages</a> once you
have created an account there. The old <a
href="feature-requests.html">list of missing features</a> have not
yet been moved over to Bugzilla.</p>
<hr />
<h2>Pretty pictures</h2>
<p>Here are some pretty pictures of simulations that were
performed with Carpet:</p>
<table>
<tr>
<td valign="top" width="10%">
<p><a href="pictures/meudon-lapse-height.png"><img
src="pictures/thumbnail-meudon-lapse-height.png" height="80"
width="80" alt="lapse height field"/></a></p>
</td>
<td valign="top" width="38%">
<p>Cut through a binary black hole system. Height field of the
lapse function (approximately the time dilatation) in a binary
black hole system calculated from Meudon initial data. The
system is cut between the two black holes, so that only one
black hole is visible. The white boxes indicate the hierarchy
of refinement regions.</p>
</td>
<td valign="top" width="4">
</td>
<td valign="top" width="10">
<p><a href="pictures/quadrupole.jpeg"><img
src="pictures/thumbnail-quadrupole.jpeg" height="80" width="80"
alt="quadrupole wave" /></a></p>
</td>
<td valign="top" width="38%">
<p>A quadrupole wave. Two rotating scalar charges create a
quadrupolar wave, mimicking the gravitational wave trail of a
binary black hole system. The small bumps and riddles are
artifacts caused by the discontinuous charge distribution. To
be improved.</p>
</td>
</tr>
<tr>
<td valign="top">
<p><a href="pictures/meudon-lapse-iso.png"><img
src="pictures/thumbnail-meudon-lapse-iso.png" height="80"
width="80" alt="lapse isosurfaces" /></a></p>
</td>
<td valign="top">
<p>Lapse isosurfaces in a binary black hole system. The same
system as above, but the lapse function is rendered as
isosurfaces.</p>
</td>
<td valign="top">
</td>
<td valign="top">
<p><a href="pictures/collapse-vel-x.png"><img
src="pictures/thumbnail-collapse-vel-x.png" height="80"
width="80" alt="velocity component" /></a></p>
</td>
<td valign="top">
<p>A velocity component in a stellar core collapse. The x
component of the fluid velocity in a stellar core collapse.
This simulation was performed by Christian Ott.</p>
</td>
</tr>
<tr>
<td valign="top">
<p><a href="pictures/multipatch-3phi-error.jpeg"><img
src="pictures/thumbnail-multipatch-3phi-error.jpeg" height="80"
width="80" alt="error function" /></a></p>
</td>
<td valign="top">
<p>The error in a multipatch numerical simulation of scalar wave
propagation in a hollow spherical shell. The coarse- and fine-grid
surface show the numerical errors (computed solution - exact solution)
computed at two different resolutions, with the low resolution error
divided by 16. The fact that the two surfaces overlap nicely shows
that the errors scale as the 4th power of the grid resolution.
This simulation was performed by Jonathan Thornburg.</p>
</td>
<td valign="top">
</td>
<td valign="top">
<p><a href="pictures/matter-density.jpeg"><img
src="pictures/thumbnail-matter-density.jpeg" height="80"
width="80" alt="matter density" /></a></p>
</td>
<td valign="top">
<p>The fate of a proto-neutron-star bar-mode deformation.
Matter density at z=0 during the transition from an m=2 deformed star
to an m=1 deformed one. The light on the right is used to emphasizes
the spiral arms which are responsible for a small mass loss.
This simulation was performed by Gian Mario Manca.</p>
</td>
</tr>
</table>
<p>Moving pictures: We can show
a <a href="movies/waveamr.gif">movie</a> (animated gif,
3.3 MB) of a scalar wave equation with adaptive mesh
refinement. The refinement criterion is a very simplistic local
truncation error estimate. We also have
a <a href="movies/bh2.gif">movie</a> (animated gif, 730 kB)
of a moving refinement region tracking a black hole.</p>
<hr />
<h2>Making sense of results</h2>
<p>Three-dimensional time-dependent simulation results are
difficult enough to interpret when the grid is uniform. With mesh
refinement, the sheer amount of available data makes it necessary
to use professional tools to examine the data. This is not only
the case for "big physics runs", where one (should) know in
advance what to expect, but especially during development, where
things do not always go as planned.
Christian Reisswig was kind enough to write
a <a href="http://www.cactuscode.org/Visualization/VisIt/">database
plugin</a> for the visualisation
tool <a href="https://www.llnl.gov/visit/">VisIt</a>. There is
also
an <a href="http://www.cactuscode.org/Visualization/ImportCarpetHDF5">import
module</a> for the visualisation
tool <a href="http://www.research.ibm.com/dx/">OpenDX</a>
available, implemented by
<a href="http://www.aei.mpg.de/~tradke/">Thomas Radke</a>.</p>
<hr />
<h2>Related projects</h2>
<ul>
<li>Physics: <a href="http://www.cactuscode.org/">Cactus</a>, <a
href="http://numrel.aei.mpg.de/">numrel@aei</a>, <a
href="http://www.whiskycode.org/">Whisky</a></li>
<li>I/O: <a href="http://www.hdfgroup.org/HDF5/">HDF5</a>, <a
href="http://www.fiberbundle.net/">F5</a></li>
<li>Visualisation: <a href="http://www.amiravis.com/">Amira</a>,
<a href="https://www.llnl.gov/visit/">VisIt</a>,
(<a href="http://www.opendx.org/">OpenDX</a>)</li>
</ul>
<hr />
<p>
<a href="http://www.xemacs.org/About/created.html"><img
src="cbxSmall.jpg" alt="Created with XEmacs!" height="36"
width="100" /></a>
<a href="http://www.anybrowser.org/campaign/"><img
src="logoab8.png" alt="Best Viewed With Any Browser" height="31"
width="88" /></a>
<a href="http://validator.w3.org/check?uri=referer"><img
src="valid-xhtml10-blue.png" alt="Valid XHTML 1.0!" height="31"
width="88" /></a>
<!--
<script type="text/javascript"
src="http://boastology.com/tools/pr/?style=2&p=1"></script>
-->
</p>
<address><a href="mailto:schnetter@cct.lsu.edu">Erik Schnetter</a></address>
<p>
<!-- Created: Tue Aug 12 12:12:08 CEST 2003 -->
<!-- hhmts start -->
Last modified: Sat Mar 01 2008
<!-- hhmts end -->
</p>
</td>
</tr>
</table>
</body>
</html>
|
