Add Bentley-Ottman Algorithm #1168
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…uts a dictionary of vertex keys with segment values
…ntersections and ultimately calculates all intersections
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@souma4 please let me know when the PR is ready for review. I have some review comments already, just waiting for your green light. |
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@juliohm Thanks for reminding me! |
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Thank you @souma4 for working on this. It is really nice to see the amazing progress you've made already ❤️
Attached is my first round of review with a couple of suggestions to improve the PR. Let's work on it together slowly, possibly improving the BinaryTrees.jl dependency before coming back here.
Looking forward to the next round. It looks very promising!
…tests. Edited test to be more intensive. updated entire script to meet style and Julia best practices. Removed unneded functions. Shifted BinaryTrees relevant materials to PR JuliaGeometry#12 in BinaryTrees and adjusted code as needed. Reordered point processing to reduce the likelihood of a bug when processing start and intersection segments.
…d function. removed println calls used for debugging
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Tests are failing because the utility function is not exported. We can either export it or qualify the calls in the test suite with the |
Co-authored-by: Júlio Hoffimann <[email protected]>
…eaner enum handling, and shifted the final dictionary to be unique values
…hes.jl into JRC_add_BentleyOttman
… that connect to the point
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@souma4 could you please rebase this PR onto the latest remote master branch? I tried to push my rebased changes following the standard git-rebase methodology, but it didn't work. Perhaps you need to enable edits in your fork? It can also be just me not knowing gitology well. |
… algorithm and to reduce redundancy.
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@souma4 I've added a test with an infinite loop. Appreciate it if you could take a look. |
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So this works, which is awesome. Problem, doing some performance testing shows its n^2. Most of the time spent (according to profview) is occurring in the intersection checks from the |
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Really nice progress. How are you checking the n^2 performance? Some tests are failing with Float32. |
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I checked time complexity with the REPL off hand. created Yeah, some tests are failing with Float32, I'm not sure why, and I'll deal with it tomorrow haha. |
| function _newevent!(𝒬, ℳ, s₁, s₂; kwargs...) | ||
| intersection(Segment(s₁), Segment(s₂)) do I | ||
| if type(I) == Crossing || type(I) == EdgeTouching | ||
| p = get(I) |
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Here we can simply call p the result of roundcoords
| # sweep line algorithm | ||
| points = Vector{P}() | ||
| seginds = Vector{Vector{Int}}() | ||
| visited = Dict{P,Int}() |
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I believe we can eliminate this visited auxiliary variable if we start the function with all points rounded. The first block of code in the function could round the coords of points and then orient the segments. Everything is done in terms of rounded coordinates.
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so when the visited variable is removed, in the second test we get a duplicate of Point((10,4)). This is because the adjacency tree can't process segment 4 crossing 10,4 until many of the other segments are dropped. And the inds variable simply pushes to the points variable.
…ght it would so I'm just hard coding the Float32 tolerance.
…e removal of ending segments from the status structure. My local tests suggest roughly logarithmic time, although caching from garbage collection makes it sort of stepwise
see issue #1126 and PR #1125
I needed to refactor and I messed up with the last draft #1143.
This produces a dictionary of vertices with a vector of segment values. Future needs: A test that the outputs are correct, and general method for rebuilding polygons with this structure.
@juliohm sorry about messing up the prior draft. Live and learn. I'll let you look this over. I think a polygon build method for this output is a new PR. This outputs vertices with segment info. If someone just wants the vertices they can grab the keys. If someone wants a polygon they can use a build method.