The
Fortran compiler
of the
GNU project
is called with gfortran.
See
this discussion
for some recommendations of options.
There is a full list of
Optimize Options
available.
Important switches are:
-fconvert=big-endian -frecord-marker=4: With this flag set, binary files in
big_endian format
(the standard for UIO files)
are automatically transformed to
little_endian
and vice versa. In addition, the old 32-bit record marker convention is maintained
and existing UIO files can be read.
-O3: General optimization flag.
-fopenmp: Activates the OpenMP directives.
-fdefault-real-8 -fdefault-double-8: Useful to force compilation
in double precision (see 4.5.5).
In 4.4.2 the preprocessor switches are listed that control the
modern - single - version uio_mac_module.F90 of the UIO module.
The scalar code is slower than code
compiled e.g. with the Intel compiler (see Sect.4.6.8).
However, the factor is not prohibitive.
For not too demanding runs the gfortran compiler can be useful.