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Computer Scientists Break Traveling Salesperson Record

quantamagazine.org

131–140 of 188 posts

Re: Computer Scientists Break Traveling Salesperson Record

#131

Earlier quoted context omitted.

I only wish the sarcasm was as painfully obvious.

If that was sarcasm, apologies. In a better world, I'd indeed assume it was, but social justice warriors have spoken to me in that manner with a straight face, and it's hard to know for sure.

"Look buddy" was supposed to be the tell.

Re: Computer Scientists Break Traveling Salesperson Record

#132
post #104
post #64

Earlier quoted context omitted.

We've banned this account for taking HN threads repeatedly into gender flamewar, and other kinds of flamewar, and ignoring our many requests to stop—such as this explanation from just two weeks ago: https://news.ycombinator.com/item?id=24569144 . Vandalizing HN like this is not cool.

Except maybe for current comment (not really, HN just has more replies on anything these days), nothing actually turned into flamewars, most out of his few "flamewar" comments over many months barely had any replies at all and were just flagged. It seems you are labeling them as flamewar just so you could justify banning him. Possibly because he expressed opinions you consider "politically incorrect" today and you wa…

When someone is routinely dropping lit matches in a dry forest, "he only started one wildfire" is obviously no defense.

Anyone who sincerely wanted to follow the rules at https://news.ycombinator.com/newsguidelines.html would be behaving completely differently. Sincere misunderstandings are generally quite easy to clear up. If someone doesn't sincerely want to follow the site guidelines, they shouldn't be posting here. We're trying for a specific kind of community.

Even the worst case is easy to fix. If someone doesn't want to be banned, they're always welcome to email hn@ycombinator.com and give us reason to believe that they'll follow the rules in the future.

Re: Computer Scientists Break Traveling Salesperson Record

#134

This is kind of a hijack, but it's at least related: Are there any websites/apps that can approximate a solution for road destinations in the real world? For example, given a list of cities, an approximate solution on actual roads to visit all of them once?

I'd say this is pretty decent but it's not a proper TSP app, since it expects the first and last points as fixed but has the option to change the order of the other stops

https://www.mapquest.com/routeplanner

Re: Computer Scientists Break Traveling Salesperson Record

#135
post #90

> able to subtract 0.2 billionth of a trillionth of a trillionth of a percent ... > “This is a result I have wanted all my career,” said David Williamson of Cornell University, who has been studying the traveling salesperson problem since the 1980s I love this. Oh to be a theoretician. Here's hoping for a flood of further improvements.

Meanwhile in an agile dev team.... "can you optimize it in the next sprint?"

Ok boss. We'll keep a cache of the best known route for the most common queries or fallback onto the existing algo.

Re: Computer Scientists Break Traveling Salesperson Record

#136

Earlier quoted context omitted.

Lately it feels like agile is where innovation goes to die :(

I agree. It’s sad. Agile principles are awesome, but by the time you run them through many company’s implementations of Scrum or SAFe or (God forbid) Jira, you may as well just do waterfall. I don’t think waterfall is necessarily bad, that agile is always right, or that there aren’t other good practices. But practicing waterfall and calling it “agile” is rarely going to end well for anyone.

Ah, not to worry. Modern agile is just waterfall, but with shorter timelines to maximize overhead costs and minimize productivity. It makes sense when you realize that we pay employees for days to elapse.

Re: Computer Scientists Break Traveling Salesperson Record

#137

Or use deep learning to generate solutions 2 orders of magnitude faster with some minor accuracy loss. https://arxiv.org/pdf/1905.05567.pdf

Apparently, heuristics are still better than DL-based solutions for the TSP

From the paper you linked:

heuristics based solutions are still superior to deep learning based solvers regarding accuracy and execution time for larger problem sizes.

Re: Computer Scientists Break Traveling Salesperson Record

#138

Earlier quoted context omitted.

Looking at the BOTW solution is doesn't seem to take into account the fact that a straight line is not the fastest solution. Climbing is incredibly slow, swimming is slow and perilous, in some places such as the dark forest you can only enter/exit in one place, not randomly, you can travel faster on roads. I guess later in the game one doesn't mind randomly walking right by the castle just because it is the shortest…

Hey man, this is just a person’s fun and imaginative side project. Is there a reason you’re offering such serious and negative critical commentary on this?

I think the parent wanted to point out that this is about a completely different problem. The algorithm mentioned works on cities that are defined with coordinates in some plane and where the distances between two points is defined as the geometric distance. The article talks about the problem where the distances between cities are given (and not based on their coordinates). The later is a much harder problem.

Re: Computer Scientists Break Traveling Salesperson Record

#139

While it is wonderful they are getting closer to solving it, if your problem is a simple and practical you can try some alternative algorithms. For fun, I used pytspsa [0] which uses the simulated annealing method to solve the TSP and applied it to BOTW. Simulated annealing was inspired by thermodynamic free energy involved in crystal formation from annealing metal. [1] I combined it with a Breath of the Wild waypoin…

Ah, I used Ant Colony Optimization to solve it a long time ago. I love simulated annealing, but in many cases the swarm based methods seem to perform better.

Re: Computer Scientists Break Traveling Salesperson Record

#140
post #72

Earlier quoted context omitted.

This is great, thanks for sharing! I had good results with genetic algorithms as well.

There are also TSP-specific heuristics that work well in practice on a lot of large instances, often finding the optimal solution pretty quickly (but with no guarantees of optimality). The first I believe was the Lin-Kernighan heuristic from 1973 (the same Kernighan as the 'K' in K&R C, incidentally). There are fast implementations of some modern improved versions, e.g.: http://akira.ruc.dk/~keld/research/LKH/

I believe that this is about a different type of TSP problem, where the distances between cities are defined by the geometric distance from their coordinates in some plane (or on a sphere). This is a simpler problem than when the distances are specified as (whole) numbers.
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