1. make sure you have two directory for the output
   (ILE2D/PREP/DATA/,ILE2D/XYPLOTS/).
   If you don't have it, create them by typing
   % mkdir PREP/DATA
   % mkdir XYPLOTS

2. Run the preprocessor in `ILE2D/PREP/' directory
   % cd PREP
   % f77 prep.f -o prep
   % ./prep

3. Run the main code in `ILE2D' directory
   % cd ../
   % f77 ile.f -o ile
   % ./ile >output.txt 

4. View the results using existing program
   % cd XYPLOTS/
   % f77 plot0.f -o plot0
   % ./plot0
   % f77 plots.f -o plots
   % ./plots
   % gv ps.dat

