Compilers & Parallel Programming

Linux Machines

Workstations, Mckenzie, Lobsters

There are 3 architectures that run GNU/Linux at CITA, x86 (ia32,athlon), x86_64 (amd64/opteron,em64t), and Itanium (1+2). The workstations are a mix of x86 and x86_64, Mckenzie is x86, and the lobsters are Itaniums. Both the Intel compilers and the GNU compiler collection are available on all of these architectures. They are respectively called icc/gcc for the C compiler, icpc/g++ for the C++ compiler, and ifort/gfortran for the Fortran compiler. Both compilers support OpenMP (as of Fedora Core 5).

Intel Compilers

• The best compilers to use in terms of code execution speed, although gcc is closing the gap
• On the old Itaniums (all except lobster6) these are called with efc/ecc
• Documentation sources in order of increasing complexity:
  • [ifort/icc/icpc] -help" will show notes about using the compiler.
  • man [ifort/icc/icpc] will display informative manual pages on compiler flags/usage
  • Fortran v8.1 and C/C++ v8.1 documentation
  • If you are returned with "command not found" when you try to use the compilers and they are not in your $PATH, make sure you are sourcing the cita optional user-template:
    source /cita/adm/conf/utemplate/useroptional.csh in your shell initialization file ~/.cshrc
• Quick optimization flags:
• full code optimization is -O3
• optimizations for a given cpu architecture:
• -tpp1 for the lobsters (itanium1)
• -tpp2 for lobster6 (itanium2)
• -tpp7 for porcupine, kodiak (pentium4)
• -tpp5 for standard pentiums
• -tpp6 for pentium pro, 2 and 3
• optimizations for a given instruction set dictated by processor type:
• -xM for processor with MMX
• -xi for pentium pro and pentium 2
• -xK for pentium 3
• -xN for pentium 4 / Xeon
• -fast enables -O3,-static, -ipo. May decrease code performance.

GCC (GNU Compiler Collection)

• Currently contains front ends for C, C++, Objective-C, Fortran, Java, and Ada, as well as libraries for these languages (libstdc++, libgcj,...).  
• In addition, G95 is installed on porcupine and the cluster at /usr/bin/g95. It has a resume from dump feature that can be signal initiated, as well as an extensive environment configuration.

Debuggers

Vendor Libraries

CFI Cluster: Dolphins; Orca; Octopus

f90 and f77 both point at the same Compaq Fortran compiler (T5.5 beta test).  Previous versions of the compilers (e.g.  V5.41) still exist;  ``ls /usr/bin/f90*' ' to see the various possibilities (these are actually scripts which set the appropriate environment variables for the desired compiler version).  To use the Compaq Fortran 77 compiler,  you must use the -old_f77 option with the f77 command.

Latest release notes are in /usr/lib/cmplrs/fort  (for Fortran 77) and  /usr/lib/cmplrs/fort90 for Fortran 90). See the man pages for  f90 (or f77 ) to get more details.

NOTE that f95 should be pointing  at the NAGWare Fortran 95 compiler  ("which f95" will show "/cita/local/bin/f95").  "man f95" for more details.

• PS version of Compaq Fortran User Manual
• PS version of Compaq Fortran Parallel Processing Manual for Tru64 Unix Systems
• description of Compaq MPI
• PDF version of Compaq MPI User Guide
• CXML: Compaq Extended Math Library

The C compiler on the dolphins is cc and the C++ compiler is cxx - Please read their man pages for detailed descriptions of their usage.

In addition to these compilers, there are also the KAP preprocessors installed on the CFI cluster.  These can be accessed as kapf90, kapf and kapc for the Fortran 90, Fortran 77 and C versions respectively.  The KAP preprocessors can be used to generate source code which is optimized as well as including OpenMP compiler directives for use on SMP machines.  Please look at the man pages for the above for further details.

Parallel Programming