Speeding up your code

First you should try to get an idea which routines are consuming most of your CPU time:

• Use the "-p" option together with your usual compiler flags.
• Recompile the whole code.
• Run the code with a sample job card. This will generate an additional file called "gmon.out".
• After the succesful run, just execute "gprof main.x gmon.out" which gives you the amount of consumed CPU time per subroutines.

Now the hard part starts : Reducing the run time of the main consumers...