gfortran: error: unrecognized command line option ‘-r8’

[R Ram]

When I tried to install a numerical code in cluster, I encountered the following error. Based on the error message, I understood that the installed gnu fortran version do not recognize the command option -r8.

Error message 

gfortran: error: unrecognized command line option ‘-r8’; did you mean ‘-k8’? gfortran: error: unrecognized command line option ‘-i-dynamic’; did you mean ‘-rdynamic’?

Fortran version

GNU Fortran (GCC) version 7.2.0

Can you please help me with this? In addition, do you know how to change the flag -r8 to -fdefault-real-8?

I have also attached the link of thread that discusses a similar issue (but, I wasn't able to solve my issue using that information). #Please let me know for any other question.

https://www.linuxquestions.org/questions/linux-newbie-8/unrecognized-command-line-option-%91-r8%92-4175463774/

Thanks in advance

Ram