1. LiveViz – What is it? Charm++ library Visualization tool
Inspect your program’s current state
Client runs on any machine (java)
You code the image generation
2D and 3D modes
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2. LiveViz – Monitoring Your Application
LiveViz allows you to watch your application’s progress
Can use it from work or home
Doesn’t slow down computation when there is no client
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3. Documentation
Or,(same material) section 6 of:
There are example programs, but:
Old ones will not work (see the warning in section 6.7)
Make sure liveVizInit call takes the 4th “opts” parameter, which means you are looking at an example with modern correct interface
See:
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4. How to use LiveViz
Get the Java Client: LiveViz (from ccs_tools) on to your desktop machine
How to run the charm program as a liveviz server
How to connect the client to server
How to construct the image/s
On demand (This is what we will focus on)
In Push mode
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5. LiveViz Client Client runs on your desktop
Server may be a remote machine,
or as a special case, for testing, your desktop
Client is a java app
Download (git clone) ccs_tools from charm website
The tool is in ccs_tools/bin/liveViz
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6. Running LiveViz Build and run the server Or in detail…
cd examples/charm++/wave2d/
make
./run_server
Or in detail…
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7. LiveViz Request Model – On demand
Client
LiveViz Server Code
Get Image
Send Image to Client
Image Chunk Passed to Server
Forward request to application
Server Combines Image Chunks
Parallel Application
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8. When you run your charm++ program
1234 is a port number
You can (and should) use other port numbers
Tell the client the same # that you give to the server
In repeated runs, change the port#.. It stays in use for several seconds after the program is terminated.
./charmrun ./wave2d+p2 ++server ++server-port 1234
~/ccs_tools/bin/LiveViz localhost 1234
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9. Wave 2D Example Structure
Main: Setup 2D worker array, initialize chares with a circular wave within the interior of the grid Workers: Start looping Send pressure messages to all neighbors with ghost rows Wait for all neighbors to send ghost rows to me Once they arrive, calculate new pressure values Advance to next timestep If total iterations completed, exit
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10. LiveViz Setup
#include <liveVizPoll.h> void Main::main(. . .) { // Do misc initialization stuff // Create the 2D workers and register with liveviz CkArrayOptions opts(chareArrayWidth, chareArrayHeight); arrayProxy = CProxy_Wave::ckNew(opts); // Setup liveviz CkCallback c(CkIndex_Wave::requestNextFrame(0),arrayProxy); liveVizConfig cfg(liveVizConfig::pix_color,true); liveVizInit(cfg,arrayProxy,c, opts); // Initialize the library // Each chare starts and sets up initial pressure pertubations }
Register Callback
for sending images on-demand
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11. On-demand image generation
//Callback function to generate images on request from client void requestNextFrame(liveVizRequestMsg *m){ unsigned char *intensity= new unsigned char[3*w*h]; for(int i=0;i<myheight;++i){ for(int j=0;j<mywidth;++j){ double p = pressure[i*mywidth+j]; if(p > 0) // Positive values are red intensity[3*(i*w+j)+0] = 255; // RED component else // Negative values are blue intensity[3*(i*w+j)+2] = 255; // BLUE component } //populate intensity with RGS based on pressure value liveVizDeposit(m, sx,sy, w,h, intensity, this);
Rectangular portion of the image
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12. LiveViz Summary Easy to use visualization library
Simple code handles any number of clients
Doesn’t slow computation when there are no clients connected
Works in parallel, with load balancing, etc.
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