Slashdot Mirror

Ok, I'm going to have to make one of those rare corrections. (ha!) It was on the fun3d.larc.nasa.gov website and on some of their other CFD pages, but is no longer present. If you go to g95's website and look under status (or just go to http://www.g95.org/g95_status.html), and look for fun3d, you will see an excerpt from the authors to the same effect.

fine, I'll feed the troll.

Parsing perl with wet-ware isn't always easy. Obfuscating your code in the name of optimization should be countered with good commenting. Every useful script will have to be maintained, and the grandparent post is totally correct. I work minor miracles with Perl; or, miracles to me, anyway--I couldn't have created my dissertation data without Fortran--specifically g95--and Perl.

I know there are lots of useful languages out there. Every language has its fanboys. Heck, I liked the PDP-11 macro language a lot. If people produce useful code with Perl, don't complain about it; be glad for them.

The only final decision you should be worried about with a modern compiler is, "is that result correct?" You've fallen into the trap of believing that your programs are the first to be written that way (they aren't), and that you're smarter than the teams of people who write compilers, and the computer scientists whose algorithms those compilers employ (chances are, you aren't).

Once again, from the real world, I have moved a quarter of a million line parallel Fortran program to a new 64-bit architecture, which was easy because the authors had isolated the machine-specific bits, and had abstracted them as far as possible, so very little actually had to be changed. After that, it was a matter of verifying the code via the official test suite and some personal results (basically, similar jobs, but larger). That code is heavily optimized by algorithmic choice, does a few (carefully isolated) architecture-dependent tricks to save memory, and makes heavy use of system math libraries (i.e. good algorithms, carefully tuned). The kind of bit-twiddling you're advocating, while probably personally fulfilling, is making very little difference in the overall performance of your code, if not actively reducing it.

Your idea of second-guessing the compiler, optimization by optimization, is (politely) impractical, on anything much over a couple of hundred lines. Go to http://www.g95.org/g95_status.html/, pick one of the simulation codes listed, such as AbInit, and convince yourself that you will consistently hand-generate better code than a modern compiler. I know some groups who do hand-coding in assembler, but that tends to be for mathematical primitives. Higher-level functions are written to call those primitives, and left to the compiler to optimize.

I said this elsewhere, but it applies here as well, "Machines should work, People should Think".

"I have no idea why the folks at Sun think that Fortran is their competitor."

Maybe because of the inroads from free (GPL) compilers such as G95 and gfortran. Remember, SUN like open source when it suits them.

This is rather unfortunate as both projects just advance slowly as they suffer a lack of developpers.

Marcel

At present, there are numerous features of Fortran 95 that gfortran (the gcc Fortran 95 compiler) does not handle correctly. G95 http://www.g95.org/, from which gfortran forked, is closer to being a full Fortran compiler. One can search the Usenet group comp.lang.fortran to confirm these statements.

If you just want a free Fortran 95 compiler use g95. Bugs reported to Andy Vaught are usually fixed quickly, and fresh Linux compiler binaries are posted almost daily. If you want to participate in the development of a Fortran 95 compiler, gfortran is more democratic.

and an even better, almost working one, g95 -- this is the code base that the gfortran people forked from. gfortran does not work, and is much further behind than g95.

statistics:
R http://www.r-project.org/
WinBugs http://www.mrc-bsu.cam.ac.uk/bugs/winbugs/contents .shtml

symbolic mathematics:
Maxima http://maxima.sourceforge.net/

numerics:
Octave http://www.octave.org/
Scilab http://scilabsoft.inria.fr/
g95 (Fortran 95 compiler)http://www.g95.org/

Besides gfortran, which is part of GCC, there is also the free g95, with compiler binaries for Mac OS X, Linux, and Windows -- see http://www.g95.org/ . G95 currently supports almost all of Fortran 95, unlike gfortran. Absoft sells their own Fortran 95 compiler for Mac OS X, in addition to IBM's -- see http://www.absoft.com/ . NAG has also has an F95 compiler -- see http://lists.apple.com/archives/scitech/2002/Jul/m sg00076.html .