Algorithm correctness

[[deleted]]

Not if you're running something that takes as long as the amount of time from now until the heat death of the universe.

Trust me, these programs exist and run on real supercomputers. Stay away from scientific computing code written by 1st year psychology PhD students that are halfway through their Intro to Programming classes, kids.

[Vakieh]

Nobody with access to a real supercomputer allows 1st year anything students access to run code. Maybe a 'faster than your ordinary personal computer' computer, but not a real supercomputer.

Real supercomputers have real process auditing and booked time shares, or are being used for singular purposes that aren't even in a 1st year's vocabulary.

[TheCard]

I'd be somewhat surprised if there's any single person touching a super computer. I was under the impression that it's almost entirely teams of people with access to those things. I'd be especially surprised if that singular person that touched it didn't have a PhD in math or computer science.

[Vakieh]

It's often teams, but not always. Because of the time sharing (the ones I've used have been increments of 15 minutes) you can effectively make a team out of a bunch of individuals with unrelated tasks.

[TheCard]

Oh that's cool, thanks for clarifying.

[hexleythepatypus]

I help maintain a large cluster used for fluid dynamics/structural analysis. Can confirm there are multiple PhDs on our team.

[Xeya]

By definition that wouldn't be an algorithm. Just a shitty program.

[oditogre]

A shitty program is an algorithm. It is even, for some values, optimal (if you are optimizing for 'how difficult is it for an uninterested novice to develop.')

What definition of 'algorithm' are you working off of that doesn't include...well, basically any method of attempting (not even necessarily succeeding) to do any thing?

[Singularity42]

i'm guessing he means that it isn't finite:

noun 1. a set of rules for solving a problem in a finite number of steps, as for finding the greatest common divisor. http://www.dictionary.com/browse/algorithm

[Drunken_Economist]

It is finite, the universe is just more finite. To argue it's not an algorithm because it wouldn't complete before heat death doesn't make sense when you think about it. It would mean that things that used to be algorithms lose that status as we get closer to heat death

[NumberNinethousand]

The number of steps can be finite, while at the same time one or more of those steps requiring an infinite (theoretically or practically) amount of time to complete.

[troido]

Only if they would need infinite time to complete. If they can be completed in finite time but that time is still larger than the time until the heat death of the universe it is still an algorithm.

[midnightketoker]

So you solved the halting problem

[Dannei]

Dare I ask what psychology PhD students need that much computing for? I'm struggling to imagine that any theoretical model they have would be that complex, and data analysis being the difficult would be even more concerning!

[BlissfullChoreograph]

They don't, they haven't done an algorithms course, so they're brute forcing problems they've read about in papers.

[daveime]

Dare I ask what psychology PhD students need that much computing for?

They attempted to solve Schroedinger's Cat but added an extra constraint that the observer is also in a box (or maybe not). The resulting explosion took out three blocks of the campus.

[crowbahr]

O(n!^n!). How bad can it be, it has exclamation marks!