[lmm]

How often are there competing implementations in scientific computing? Most of the time people are doing just enough to publish a paper, or maybe maintaining a single library that everyone uses. Few people have the inclination, and even fewer the funding, to "rewrite everything".

In finance, which has a lot of parallels with scientific computing but tends to end up with semi-secret, parallel, competing implementations of the same ideas, functional programming has had significant (though by no means universal) success in doing exactly what you describe.

[dekhn]

Let's see. The two big codes I worked with- BLAST and AMBER- have competitors. For BLAST there have been a long history of codes that attempted to do better than it, and I don't think anybody really succeeded until that except possibly HMMER2. Both BLAST and HMMER2 had decades of effort poured into them. BLAST was rewritten a few times by its supporting agency (NCBI) and the author(s) of HMMER rewrote it to be HMMER2. I worked with the guy who wrote the leading competitor to HMMER, he was an independently wealthy computer programmer (with a physics background). In the case of AMBER, there are several competitors- gromacs, NAMD, and a few others are all used frequently. AMBER has been continuously developed for decades (I first used it in '95 and already it was... venerable).

All the major players in these fields read each other's code and papers and steal ideas

In other areas there are no competitors, there's just "write the minimal code to get your idea that contributes 0.01% more to scientific knowledge, publish, and then declare code bankruptcy". And a long tail of low to high quality stuff that lasts forever and turns out to be load-bearing but also completely inscrutable and unmodifiable.

After typing that out I realize I just recapitulated what you said in your first paragraph. My knowledge of finance is limited beyond knowing "jane street capital has been talking about FP for ages" and most of the people I've talked to say their work in finance (HPC mostly) is C++ or hardware-based.