gravitator_daemon is an addon program for the Gravitator program. It calculates the gravity simulation and stores it's results in a
file. The advantage is that you can have it to save only every n-th frame of the simulation, so you can set a high speed division (the
higher the speed division, the shorter the time step and so the more accurate is the simulation) and by saving only every 100-th frame
(for example..) you can watch the simulation go very fast. gravitator_daemon doesn't display the simulation, it only calculates it It's
intended to run in the background while you're doing something else.
The installation process is standard. Unpack the source .tgz, enter the gravitator_daemon directory, run ./configure and make. You can
also run make install, but you don't really need it, you only need the executable, which is in subdirectory gravitator_daemon. You can
copy the executable wherever you want. Gravitator requires standard libraries and headers and the popt library (you probably have it)
and it's headers.
Command line options
The program is controlled via command line options, which are:
- -i FILE, --input_file=FILE - select the file with the world which will be simulated
- -o FILE, --output_file=FILE - select the file to which will the simulation be saved
- -s DIVISION, --speed_division=DIVISION - set the speed division
- -f FRAME, --frame_skip=FRAME - set every which frame will be saved
- -t FRAMES, --total_saved_frames=FRAMES - how many frames shall be saved
- -h, --help - show help
After starting the program, the calculation starts. It will stop after calculating every requested frame, or after receiving the SIGINT
signal (this is done by Ctr+C for example). Notice that the output file can get very large, it's final size will be the size of the
input file multiplied by the number of saved frames. While it's running, it'll show which frame is it calculating and which one is it
saving. There is a sample shell script in the gravitator_daemon/gravitator_daemon directory which shows how to run the program.