I am trying to run a code named "garfield-7". when I run it the message "segmentation fault" appears. Why this error appears and how i can solve this problem.

Tavassoli - Welcome to LQ,

A Segmentation Fault means that the application has crashed, because of some error in the program.

If this is something that you have downloaded, or is it code that you have written ?
Do you have the right version for your distribution ? What is your distribution?

We need some more info on what you have done so far.

Like to help you, hear from you soon.

A segmentation fault means that the program you're running attempted to read or write some address in memory that wasn't assigned to it. Try running strace and see whats wrong

Thanks "nabeelmoidu" for your answer
What is "strace" and how can run it?

strace garfield-7 will give you the system calls that the code produces while executing your program.You might be able to identify which file or piece of code might be causing the problem . I don't know exactly how much it will help your issue, but you can give it a try.I normally use it when any program crashes or so.
As worzel68 said , give us an idea of what garfield is ? And paste exactly the error you are getting.

I looked at the web page:

It looks like you have downloaded a binary file for Redhat 6.1 or SLC3, neither of which will work on your REdhat 7.3.

I suggest that you download the source files from that page & compile it your self. There is an email link on the page to receive instructions on compiling, which is advisable as the code is written fortran (not easy) although not impossible as most linux distros come with a g77 compiler.

BTW you are another guy who seems to have a really old version of Redhat - since 7.3 there have been Redhat 8, 9 & Fedora 1, 2, 3, 4 & 5 which is the latest. Sorry I don't mean to be rude , But Crikey!!

Any way have a go with the compile instructions from CERN

Have fun with the fortran code