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Comment by toomanybeersies | Hacker News Reader

I've never worked with a board with curvy traces like that before, but I don't think I'd like them. They look a lot harder to debug than straight traces with 90 and 45 degree angles.

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Some autorouters have options to only use 45 or 90 degree traces where possible (in fact some of the examples in the link show this behaviour). In a similar vein, I'd like to see an autorouter that also cares about ground plane impedance and continuity: attempting to avoid ground plane islands or regions where clearances prevent ground planes from separating tracks, and even trying to keep ground planes associated with tracks in certain classes (e.g. high speed vs power lines) separated, joining only at the external power supply jack.

But, given the autorouting problem's NP hardness, especially when there are extra constraints like above, I expect that manual routing for anything beyond trivial layouts will continue to be the norm.

Can humans magically solve NP hard problems that computers can't? I don't think so...

Humans make use of the fact that the optimal solution is not necessary (or probably even desirable, given the multitude of parameters to optimize for). By heuristics we can find a good solution that is also understandable to others.

A computer can understand that an optimal solution is not always needed. There is nothing about the problem being NP complete that means the computer HAS to find the optimal solution.

Humans are capable of deriving and applying new knowledge about a problem while solving it. So when confronted with a specific NP hard problem, a human solver applies intuition and thereby restricts the solution space that must be searched significantly. These intuitive rules can be very specific to the problem. There is no good computer algorithm that can do the same combination of creating and applying rules automatically.

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