Wanted: Ancient Fortran FFT source code

In summary, The conversation is about legacy code and the speaker is looking for the pre-Fortran77 source code of an old FFT implementation they worked on in the late 1990s. They describe the code as having implicit typing, single letter variable names, all caps, no commenting, and being written by someone at UC Berkeley in the mid-1960s. They are wondering why this code is still in use and ask for any pointers to the source code. Another person responds that there is nothing shocking about this and that in the past, editing options were limited, so shorter variable names were used. They also mention a website that may have the code the speaker is looking for.
  • #1
cdenzler
1
0
Hi.

I'm new here and wasn't sure which forum to post this request on, but this one seemed a good start.

I am developing a talk/seminar on dealing with legacy code. In the late 1990s I was working for a large corporation in a software capacity and one day idly wondered what the source code looked like that was actually performing the FFT in the application I was working on.

As near as I can recall, the code had the following features: Implicit typing, single letter variable names, source code in all caps, no commenting, and was very terse. I think I recall at the top of the file, the code was written by someone at UC Berkeley, but I could be wrong about that. I recall clearly that there was a date in the header comments, from the mid-1960s. It must have been an early implementation of the Cooley-Tukey algorithm.

At the time I was shocked that at the bottom of the call stack was this (then) 30-year old Fortran code that was doing an enormous amount of heavy lifting for this (very large) corporation. The code was ugly to look at, but there must have been a reason that it was still in use at the time.

I am looking for the source code, pre Fortran77, of this ugly gem if it rings any bells.

Thank for any pointers,

- Chris
 
Technology news on Phys.org
  • #2
There is nothing very shocking about this. The compiler doesn't care if the code looks ugly, so long as it works.

Most high speed computer printers from the 1970s era only printed upper case letters.

Creating a deck of punched cards for program input, there were NO editing options whatever, except for throwing away a card and retyping the complete line. That didn't encourage using longVariableNamesWithRandomlyInsertedUpperAndLowerCaseCharacters.

In any case, the mathematical description of the FFT would have been written with one-character "variable names", just like almost every other piece of mathematics. Making the variable names longer when you translated the math into Fortran didn't add any value - in fact it was a good way to make mistakes.

"Real programmers" have better things to do than rewrite working code just to make it look pretty!
 
  • #3

1. What is Fortran?

Fortran is a programming language used for scientific and engineering applications. It was developed in the 1950s and is still used today for high-performance computing and numerical analysis.

2. Why is the source code for "Ancient Fortran FFT" wanted?

The Fast Fourier Transform (FFT) is a widely used algorithm in scientific computing. The "Ancient Fortran FFT" refers to the original implementation of the FFT in Fortran, which is of historical and scientific significance. Researchers may be interested in studying this code for educational or historical purposes.

3. Is the source code for "Ancient Fortran FFT" still relevant?

While the original implementation of the FFT in Fortran may not be used in modern applications, it is still relevant for understanding the development and evolution of the FFT algorithm. It can also serve as a benchmark for comparing newer and more efficient versions of the FFT.

4. Where can I find the source code for "Ancient Fortran FFT"?

The source code for the "Ancient Fortran FFT" can be found in various online archives and repositories, such as the Netlib repository or the ACM Digital Library. It may also be available in academic or historical publications.

5. Can the "Ancient Fortran FFT" source code be used in modern applications?

The "Ancient Fortran FFT" source code may not be directly usable in modern applications due to changes in computer architectures and programming languages. However, it can serve as a valuable reference for implementing the FFT algorithm in modern languages and applications.

Similar threads

Fortran Identify explicit shape spec list in the FORTRAN code
    • Programming and Computer Science
Replies
1
Views
2K

Hot Threads

Recent Insights

Back
Top