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First improvement of fundamental algorithm in 10 years

web.mit.edu

11–20 of 42 posts

Re: First improvement of fundamental algorithm in 10 years

#11
post #7

Earlier quoted context omitted.

Kelner is set to give a talk about it tomorrow[1]. Anyone know if they create videos for these? [1]: http://www.csail.mit.edu/events/eventcalendar/calendar.php?s...

The method sounds very interesting, but the title seems to overstate the work a bit. This is an approximation algorithm, meaning that it's an improvement on an _approximate_variant_of_ a fundamental problem, right?

[deleted]

Re: First improvement of fundamental algorithm in 10 years

#13
post #2

The article refers to the max flow problem. About all this article does is imply that the new method involves the adjacency matrix of the graph and provides little else in the way of details. A better article is needed, not this oversimplified press release.

Kelner is set to give a talk about it tomorrow[1]. Anyone know if they create videos for these? [1]: http://www.csail.mit.edu/events/eventcalendar/calendar.php?s...

Any MIT people know if this is open to the public? Might be worth leaving work a bit early to listen to that talk.

Re: First improvement of fundamental algorithm in 10 years

#14
post #2

The article refers to the max flow problem. About all this article does is imply that the new method involves the adjacency matrix of the graph and provides little else in the way of details. A better article is needed, not this oversimplified press release.

Adjacency matrices are taught in undergraduate linear algebra classes. This article makes it sound like they invented them.

Re: First improvement of fundamental algorithm in 10 years

#15

Earlier quoted context omitted.

Kelner is set to give a talk about it tomorrow[1]. Anyone know if they create videos for these? [1]: http://www.csail.mit.edu/events/eventcalendar/calendar.php?s...

Any MIT people know if this is open to the public? Might be worth leaving work a bit early to listen to that talk.

The email note and notice in the elevator says "THEORY COLLOQUIUM: Open to the Public".

Re: First improvement of fundamental algorithm in 10 years

#16
It's an approximate algorithm (nothing wrong with that).

I'm confused at how they claim O(m^{4/3}) (m is the number of edges) when even initializing an explicit n by n matrix is O(n^2), unless they assume that the graph isn't sparse (m>=k*n^1.5).

Or perhaps the matrix is sparsely represented.

Re: First improvement of fundamental algorithm in 10 years

#17
post #7

Earlier quoted context omitted.

Kelner is set to give a talk about it tomorrow[1]. Anyone know if they create videos for these? [1]: http://www.csail.mit.edu/events/eventcalendar/calendar.php?s...

The method sounds very interesting, but the title seems to overstate the work a bit. This is an approximation algorithm, meaning that it's an improvement on an _approximate_variant_of_ a fundamental problem, right?

If you're able to find a rapidly converging sequence of approximations, then in finite time you can approximate arbitrarily well. Given the realities of finite numerical precision, this can be exactly as useful as an exact solution.

We'll know more tomorrow.

Re: First improvement of fundamental algorithm in 10 years

#18
post #7

Earlier quoted context omitted.

Kelner is set to give a talk about it tomorrow[1]. Anyone know if they create videos for these? [1]: http://www.csail.mit.edu/events/eventcalendar/calendar.php?s...

The method sounds very interesting, but the title seems to overstate the work a bit. This is an approximation algorithm, meaning that it's an improvement on an _approximate_variant_of_ a fundamental problem, right?

I think the title is appropriate. The approximate solution is the interesting one, as the exact solution is believed to be intractable.

Re: First improvement of fundamental algorithm in 10 years

#19
post #8

Very little info, but I'd argue that the parallel qualities of the new algorithm are at least of similar importance to the improvement in complexity. Old speed: (N + L)^(3/2) New speed: (N + L)^(4/3). (n=nodes, l=links) > For a network like the Internet, which has hundreds of billions of nodes, the new algorithm could solve the max-flow problem hundreds of times faster than its predecessor. Granted, it's massively us…

[deleted]

Re: First improvement of fundamental algorithm in 10 years

#20
This sounds cool, but how is this not a solution that's already been considered? It seems intuitively obvious to me that you can use a circuit simulator to solve this problem pretty quickly by assigning conductances to the edges of the graph. Modern circuit simulators are pretty good at converging on a solution in the presence of strong nonlinearities, so in principle you could even have edges that are more than simple conductances.

(I have a CS degree, but I'm a circuit designer, so it's been a while since I've thought seriously about problems like this and I'm clearly not in touch with the state of the art. This question isn't snark, it's really a question.)

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