Re: Is Linux Unix?
Paul E Condon <pecondon@mesanetworks.net> wrote in message news:
[...]
> > I'm using the Intel Fortran Compiler (IFC). Its version 7 runs on Debian
> > without any problem whatsoever, although Intel doesn't support Debian. But,
> > last year Intel released a total rewrite of the compiler, version 8, with
> > which my Fortran programs don't work at all [...]
>
> If your programs work with version 7, why do you feel a need to
> migrate to version 8? Well maybe because version 7 will become
> unavailable soon (?).
For a couple of reasons. One is that Intel doesn't want to fix bugs in
version 7. For example, I discovered a problem in version 7 and reported
it to Intel. They aknowledged that it is indeed a problem, but they say they
won't fix it because version 8 doesn't have the problem. They strongly urged
me to migrate to version 8. I suspect that they wish they hear nothing
about version 7 and want to pull out as soon as possible.
Another reason is that I'm not sure if you can get a copy of version 7 for
free any more. When I installed version 7, I didn't think it will go away
so that I didn't store the package. Now, what if my machine crashes and I
need to install the compiler again?
> Would migrating to the GNU fortran compiler be
> more or less work than migrating to intel version 8?
I haven't used the GNU Fortran 95, but I'm 98% sure that it's almost
unusable at this stage. Since I've had *enough* unpleasantness with new
compilers, I'm very reluctant to give the GNU compiler a try at this stage.
For example, I had to report a couple of internal compiler errors for the
then new Sun Fortran 95 compiler. I again reported a few internal compiler
errors for the 2nd version of Sun F95 compiler, and it emitted obviously
wrong code in certain cases if you switch on the optimizer. Then the initial
releases of the 3rd version of the same compiler gave me a few internal
compiler errors. I think the Sun compiler at last reached a mature stage
at the later releases of the 3rd version. I had very similar experience with
another vendor, too.
Also, I heard that the optimizer for the GNU F95 compiler is almost nothing
at this stage. I recently found one of the programs I use runs six times
faster with -O3 than without on an SGI machine (I'm not using automatic
parallization, so the speedup is a genuine improvement due to the optimizer).
I mean, the optimizer is really important for the type of computations I'm
doing. Speed comparisons by other people between the GNU Fortran 95 and the
Intel compiler show similar difference in performance.
> (Or migrating to C/C++?)
That's out of question! :) For numerical computation, Fortran 95 is "better"
than C++. (I have plenty of experience in C++ programming.) Sure I greatly
miss C++'s objects and templates and other goodies. But codes for numerical
computation can be much more "easily" written in Fortran 95. That's the most
important point for a non-proffessional programmer like me.
> If you were to migrate to GNU, you would be safe from the need
> to ever migrate again. You just have to keep a safe copy of the
> source.
Yes. I'm waiting for the day when the GNU Fortran 95 becomes as mature
as the GNU C compiler. But, then the most commercial compilers will have
been supporting Fortran 2003, and I will want to use some of the F2003's
features. In this area, open source software lags far behind, sadly.
Cheers,
Ryo
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