[petsc-users] Warning at the beginning of compiling

[Edoardo alinovi]

Dear users,

what does this warning means?

 ***** WARNING: Using default FORTRAN optimization flags -g -O

                               You might consider manually setting
optimal optimization flags for your system with

FOPTFLAGS="optimization flags" see config/examples/arch-*-opt.py for
examples


thank you very much,

Edoardo