forked from OSchip/llvm-project
cd93d7ef43
Summary: SetVector uses both DenseSet and vector, which is time/memory inefficient. The points are represented as natural numbers so we can replace the DenseSet part by indexing into a vector<char> instead. Don't cargo cult the pseudocode on the wikipedia DBSCAN page. This is a standard BFS style algorithm (the similar loops have been used several times in other LLVM components): every point is processed at most once, thus the queue has at most NumPoints elements. We represent it with a vector and allocate it outside of the loop to avoid allocation in the loop body. We check `Processed[P]` to avoid enqueueing a point more than once, which also nicely saves us a `ClusterIdForPoint_[Q].isUndef()` check. Many people hate the oneshot abstraction but some favor it, therefore we make a compromise, use a lambda to abstract away the neighbor adding process. Delete the comment `assert(Neighbors.capacity() == (Points_.size() - 1));` as it is wrong. llvm-svn: 350035 |
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| clang | ||
| clang-tools-extra | ||
| compiler-rt | ||
| debuginfo-tests | ||
| libclc | ||
| libcxx | ||
| libcxxabi | ||
| libunwind | ||
| lld | ||
| lldb | ||
| llgo | ||
| llvm | ||
| openmp | ||
| parallel-libs | ||
| polly | ||
| pstl | ||
| README.md | ||
README.md
The LLVM Compiler Infrastructure
This directory and its subdirectories contain source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and runtime environments.