fortran compiler option help

[Tobias Burnus]

Micah Sklut wrote:
> Using the intel compiler, I am using the following options

For the gfortran options, check the gfortran *and* the gcc manpage as 
the gfortran man page does not repeat all of the general gcc options. 
Cf. http://gcc.gnu.org/onlinedocs/ (there: "GCC <version> Manual" and 
"GCC <version> GNU Fortran Manual").

> -c  (prevents linking)
That's -c (compile only)

> -module (module directory)
That's  -J, though older gfortran version accepted additionally (or only) -M

> -o (specifies name for output file)
That's also -o

> -C (check for certain conditions at run time).

That's -fcheck=all (or other options); with older gfortran's try 
-fcheck-bounds and some others.

> This is the full command that I am using with my compile script:
> ifort -xT -ipo -c -module mod_dir -parallel

For -xT use -march=native (or a suitable -march= option). For -ipo try 
"-flto" on GCC 4.5 or 4.6. For -parallel, you can try 
-ftree-parallelize-loops=n

Additionally, you probably want to use -O2 or -O3 (= optimization level; 
default of ifort is -O2; the default of GCC/gfortran is -O0) - and maybe 
-funroll-loops or -ffast-math. (Check the manual thus you know what the 
option means.)

Tobias