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Title: A Note on Compiling Fortran

Technical Report ·
DOI:https://doi.org/10.2172/1393322· OSTI ID:1393322
 [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

Fortran modules tend to serialize compilation of large Fortran projects, by introducing dependencies among the source files. If file A depends on file B, (A uses a module defined by B), you must finish compiling B before you can begin compiling A. Some Fortran compilers (Intel ifort, GNU gfortran and IBM xlf, at least) offer an option to ‘‘verify syntax’’, with the side effect of also producing any associated Fortran module files. As it happens, this option usually runs much faster than the object code generation and optimization phases. For some projects on some machines, it can be advantageous to compile in two passes: The first pass generates the module files, quickly; the second pass produces the object files, in parallel. We achieve a 3.8× speedup in the case study below.

Research Organization:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Organization:
USDOE
DOE Contract Number:
AC52-07NA27344
OSTI ID:
1393322
Report Number(s):
LLNL-TR-738243
Country of Publication:
United States
Language:
English