WaveToy Demo
On this page we describe one of our standard demonstrations,
which includes various tools which can be used with
your own application, including
- Remote monitoring and steering of an application from
any web browser
- Streaming of isosurfaces from a simulation, which can
then be viewed on a local machine
- Remote visualization of 2D slices from any grid function
in a simulation as jpegs in a web browser
This is a good example for you to try out yourself if you
are trying out Cactus for the first time, or haven't used
some of these tools before. Note that you only need a C
compiler for this, and about 50MB of free diskspace.
The application we are using is the simulation of the
3D scalar field produced by two orbiting sources. The
solution is found by finite differencing a hyperbolic
partial differential equation for the scalar field.
This is a very simple application, however it is
representative of a large class of more complex systems,
including Einstein's Equations, Maxwell's Equations, or
the Navier-Stokes Equations. We use it for demonstrations
since the simulation is not computationally intensive,
is very robust, has simple parameter choices, and has
reasonable graphics.
We are not going to describe completely here how to checkout
and compile this Cactus application ... for this see the
information on the Download
page, the HOWTOs
or the
Users
Guide. We assume
that you are checking out Cactus using CVS, and that you know
the configuration line needed, or have a configuration file,
for compiling Cactus.
Demo with Web Server and Streaming IsoSurfaces
Before you start, make sure you have the following items:
- GetCactus the perl script
for easily checking a Cactus application out from our
CVS server.
- WaveDemo.th
the ThornList for the demo, this is used to tell GetCactus
which thorns to get. To use the development version of the thornlist found here: WaveDemo.th
- WaveDemo.par
a parameter file for running the demonstration.
- IsoView
the isosurface visualization client.
- A web browser.
- Note that you'll need a live network connection to checkout
the code, but you can run the demo on a single machine, the
remote tools will look more impressive though if you use two
networked machines, preferably a long way apart.
- If you want you can also try this with the development version
WaveToyDevelopment
Check out and compile
Checkout the source code using the GetCactus script. Make sure to include the WaveToy thornlist so that all necessary thorns are also downloaded.
chmod u+x GetCactus
./GetCactus WaveDemo.th
You should be able to use the default answers for all the
questions.
Once the checkout has completed, move into the Cactus directory and compile the application.
cd Cactus
gmake WaveDemo-config
gmake WaveDemo
Hopefully that went OK, and you now have an executable,
exe/cactus_WaveDemo. Check it really worked by running
the testsuites, just type
gmake WaveDemo-testsuite
and use the default answers to each question.
Run the demo
Move the downloaded demo parameter file into the Cactus directory.
To start the simulation, run your new executable with
the demo parameter file, if you have a single processor
executable
mv ../WaveDemo.par .
./exe/cactus_WaveDemo WaveDemo.par
If you compiled with MPI and have a multiprocessor version,
you will need to use the appropriate mpi command for running.
When the simulation starts, you will see output describing for
example the activated thorns and the scheduling tree.
tg-c305 dstark/Cactus> ./exe/cactus_WaveDemo parfiles/WaveDemo.par
--------------------------------------------------------------------------------
10
1 0101 ************************
01 1010 10 The Cactus Code V4.0
1010 1101 011 www.cactuscode.org
1001 100101 ************************
00010101
100011 (c) Copyright The Authors
0100 GNU Licensed. No Warranty
0101
--------------------------------------------------------------------------------
Cactus version: 4.0.b15
Compile date: Nov 19 2004 (08:52:01)
Run date: Nov 19 2004 (08:54:30)
Run host: tg-c305.ncsa.teragrid.org
Executable: /home/ac/dstark/Cactus/./exe/cactus_WaveDemo
Parameter file: parfiles/WaveDemo.par
--------------------------------------------------------------------------------
Activating thorn Cactus...Success -> active implementation Cactus
Activation requested for
--->coordbase symbase pugh pughslab pughreduce isosurfacer iojpeg jpeg6b ioutil ioascii iobasic time wavetoyc cartgrid3d boundary idscalarwavec wavebinarysource httpd httpdextra socket<---
Activating thorn boundary...Success -> active implementation boundary
Activating thorn cartgrid3d...Success -> active implementation grid
Activating thorn coordbase...Success -> active implementation CoordBase
Activating thorn httpd...Success -> active implementation HTTPD
Activating thorn httpdextra...Success -> active implementation http_utils
. . .
Activating thorn wavebinarysource...Success -> active implementation binarysource
Activating thorn wavetoyc...Success -> active implementation wavetoy
--------------------------------------------------------------------------------
if (recover initial data)
Recover parameters
endif
Startup routines
[CCTK_STARTUP]
CartGrid3D: Register GH Extension for GridSymmetry
CoordBase: Register a GH extension to store the coordinate system handles
GROUP HTTP_Startup: HTTP daemon startup group
HTTPD: Start HTTP server
GROUP HTTP_SetupPages: Group to setup stuff which needs to be done between starting the server and the first time it serves pages
HTTPD: Serve first pages at startup
HTTPDExtra: Utils for httpd startup
PUGH: Startup routine
IOUtil: Startup routine
IOJpeg: Startup routine
IOASCII: Startup routine
IsoSurfacer: Startup routine
IOBasic: Startup routine
PUGHReduce: Startup routine
SymBase: Register GH Extension for SymBase
WaveToyC: Register banner
. . .
Termination routines
[CCTK_TERMINATE]
IsoSurfacer: Termination routine
PUGH: Termination routine
Shutdown routines
[CCTK_SHUTDOWN]
HTTPD: HTTP daemon shutdown
Routines run after restricting:
[CCTK_POSTRESTRICT]
WaveToyC: Boundaries of 3D wave equation
GROUP WaveToyC_ApplyBCs: Apply boundary conditions
GROUP BoundaryConditions: Execute all boundary conditions
Boundary: Apply all requested local physical boundary conditions
CartGrid3D: Apply symmetry boundary conditions
Boundary: Unselect all grid variables for boundary conditions
Routines run after changing the grid hierarchy:
[CCTK_POSTREGRID]
CartGrid3D: Set Coordinates after regridding
--------------------------------------------------------------------------------
Server started on http://tg-c305.ncsa.teragrid.org:5555/
INFO (what): PUGHReduce
--------------------------------------------------------------------------------
Driver provided by PUGH
--------------------------------------------------------------------------------
WaveToyC: Evolutions of a Scalar Field
--------------------------------------------------------------------------------
INFO (IOJpeg): I/O Method 'IOJpeg' registered: output of 2D jpeg images of grid functions/arrays
INFO (IOJpeg): Periodic IOJpeg output every 10 iterations
INFO (IOJpeg): Periodic IOJpeg output requested for 'WAVETOY::phi'
INFO (IOASCII): I/O Method 'IOASCII_1D' registered: output of 1D lines of grid functions/arrays to ASCII files
INFO (IOASCII): Periodic 1D output every 10 iterations
INFO (IOASCII): Periodic 1D output requested for 'WAVETOY::phi'
. . .
INFO (IsoSurfacer): Isosurfacer listening for connections
host 'tg-c305.ncsa.teragrid.org' control port 7050 data port 7051
. . .
INFO (PUGH): Local load: 64000 [40 x 40 x 40]
INFO (PUGH): Maximum load skew: 100.000000
INFO (Time): Timestep set to 0.00649351 (courant_static)
INFO (IOBasic): Periodic scalar output requested for 'WAVETOY::phi'
INFO (IOBasic): Periodic info output requested for 'WAVETOY::phi'
-------------------------------------------------
it | | WAVETOY::phi |
| t | minimum | maximum |
-------------------------------------------------
0 | 0.000 | 5.148200e-131 | 0.95066004 |
10 | 0.065 |-1.319022e-33 | 0.98026627 |
20 | 0.130 | -0.30418278 | 1.40297645 |
30 | 0.195 |-9.120612e-23 | 1.53352239 |
40 | 0.260 |-4.980518e-19 | 1.76419451 |
50 | 0.325 |-5.650478e-16 | 2.06547404 |
60 | 0.390 |-5.221892e-13 | 2.20300711 |
70 | 0.455 |-3.124912e-10 | 2.39674767 |
80 | 0.519 |-9.294138e-09 | 2.38699930 |
90 | 0.584 | -0.00000002 | 2.38045481 |
100 | 0.649 |-9.382595e-09 | 2.37422575 |
. . .
If you have the simple visualization client xgraph
installed, you can look at the 1D output
xgraph WaveDemo/phi_x_[20][20].xg
Connecting with a web browser
To connect to the simulation, move to another machine if you
have one, and start up a web browser. Connect to
http://<machine name>:5555
where <machine name>:5555 is the name of the
machine where the simulation is running. Note that this information
was part of the standard output when the simulation started for
example
Server started on http://tg-c305.ncsa.teragrid.org:5555/
Now you should see a screen with information about the
simulation.
Click through the links to find information
about the thorns, parameters and variables you are using.
Go to the ViewPort and see Jpeg images from the simulation,
if you press the refresh/reload button on your browser these will
update (you may need to press e.g. the shift button as well
depending on your browser and option settings), go to the
Files page and see some of the output files that are
being created. (If you have xgraph installed on your machine
you can set up your browser to automatically view these
when you click on them, see the WebServer-HOWTO for more
details).
Viewing IsoSurfaces
The IsoView client is currently being updated, and will be available by December 2004.
Start up the IsoView client, using
IsoView -h <machine name> -dp 5557 -cp 5558
Again, this information can be found in the standard output,
for example
Isosurfacer listening for control connections on gullveig.aei-potsdam.mpg.de port 5558/
Isosurfacer listening for data connections on gullveig.aei-potsdam.mpg.de port 5557/
You should now see rotating blobs appearing in the client, looking
something like this
Now if you move the val slider, the value of the
isosurface you see will change. Also, if you move the cursor
in the main window, holding down the left, middle and right
mouse buttons, the surface will rotate, translate and zoom.
Steering the Simulation
The web interface can also be used to control the simulation
and to steer parameter values. Click on the Cactus Control
link in the menu, and enter the user id anon and password anon
(you can set these to be different values in the parameter file).
Now you can pause, run or kill the simulation using the top
buttons. If you are using the IsoView client press pause and
see the blobs stop rotating/
The buttons at the bottom allow you to pause the simulation at
a given iteration number, or a given time, or when a condition
is true. This is just a first version of a control interface,
we hope it will become much more powerful, including many
interactive debugging and collaborative tools.
To steer simulation parameters, select Parameters from the
menu, and then WaveBinarySource. We will change the parameter
binary_radius,
which sets the distance between the orbiting sources. Note that
the parameters are divided into two sections, depending on
whether they are steerable or not. This is decided by the
thorn author.
Note that if you click on the parameter name you get all
the known information about that parameter.
Steer the parameter by changing the value in the box to
zero, and pressing the update button. If you are watching
the isosurfaces you should see the blobs move together. This
can take a short while, since the isosurfaces are of the field
and not the sources, and the field takes time to catch up.
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