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0 pointsusername2238y ago0 comments

And not without meaning. HPC people hold themselves to higher standards than the average Joes throwing stuff at the currently-fashionable "continuous integration server" until the lights turn green. "Codes" are often things that have been proven, written on a legal pad, typed into the machine, and finally validated on a set of test problems. Could you prove that your program has second-order numerical stability? https://en.wikipedia.org/wiki/Numerical_stability

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hueving8y ago· 2 in thread

A shining example of the Dunning–Kruger effect. Scientific code is some of the worst-engineered code you'll ever deal with because it's written by people that are great at physics but terrible at software engineering.

It will be poorly documented, have single letter var names everywhere without comments, have a bunch of hidden dependencies on whatever the postdoc had installed on his/her laptop, leak memory but 'terminate before it should be a problem', etc. Oh, and there will almost never be even a single regression test.

Sure, the underlying algorithm might have a nice proof of numerical stability, but the actual software is almost always trash until some poor soul has to re-engineer it if the software turns out to be useful.

username223OP8y ago

Sure, the code is usually pretty ugly, but it also tends to work. The people who write it view software as just another tool, so they care more about working than looking pretty.

> Oh, and there will almost never be even a single regression test.

Bullshit. "Codes" tend to be run against analytical and/or experimental results.

hueving8y ago

It's not about looking pretty. It's about being composable, extendable, testable, and portable to other languages and architectures.

The fact that you think looking pretty has anything to do with sound software engineering further illustrates my point.

>Bullshit. "Codes" tend to be run against analytical and/or experimental results.

A README that says the author ran it against dataset Y and got X is not a regression test. I'm talking about automated tests run on every proposed patch to ensure the thing is never broken. Real automated tests that cover 90%+ of branches are about as rare as unicorns in scientific computing (much to my annoyance).

Don't get me wrong, I completely understand why people running experiments skip testing (fast iteration). But that leads to the very opposite of "higher standards".

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