From 096589d9719564aa1a2b785d0944ca5e48fb2afe Mon Sep 17 00:00:00 2001 From: neoblizz Date: Thu, 17 Mar 2022 08:16:13 -0700 Subject: [PATCH] Preparing for a release. --- README.md | 44 ++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 40 insertions(+), 4 deletions(-) diff --git a/README.md b/README.md index 22eac76..bf3be75 100644 --- a/README.md +++ b/README.md @@ -6,10 +6,46 @@ Single-Source Shortest Path (SSSP) implementation in modern C++ for 2022 IPDPS w | Ubuntu | [Ubuntu 20.04](https://docs.github.com/en/actions/using-github-hosted-runners/about-github-hosted-runners#supported-runners-and-hardware-resources) | [![Ubuntu](https://github.com/neoblizz/sssp/actions/workflows/ubuntu.yml/badge.svg)](https://github.com/neoblizz/sssp/actions/workflows/ubuntu.yml) | | Windows | [Windows Server 2019](https://docs.github.com/en/actions/using-github-hosted-runners/about-github-hosted-runners#supported-runners-and-hardware-resources) | [![Windows](https://github.com/neoblizz/sssp/actions/workflows/windows.yml/badge.svg)](https://github.com/neoblizz/sssp/actions/workflows/windows.yml) | -## Requirements -- `C++20` for linux, `C++23` for windows. -- `cmake` version 3.22.2. -- `tbb` library for execution policies (automatically fetched using cmake). +## Dependencies +- `C++20` for linux (requires `gcc/g++-10.1` or higher), `C++23` for windows. +- `cmake` version `3.22.2`. +- `tbb` library for execution policies (automatically fetched using `cmake`). + +## Implementation Detail +This code base makes use of modern C++ features such as `ranges`, `execution_policy`, and lambda expressions to implement the essential components for parallel graph analytics. We focus on a simple implementation of Single-Source Shortest Path (SSSP), but the concepts can easily be extended to support other graph algorithms such as Breadth-First Search with minor changes to the lambda expression during traversal. + +### SSSP Traversal Condition +```cpp +[&](vertex_t const& src, // source + vertex_t const& dst, // destination + edge_t const& edge, // edge + weight_t const& weight // weight + ) { + weight_t new_d = distances[src] + weight; + weight_t curr_d = atomic::min(&distances[dst], new_d, m_locks[dst]); + return new_d < curr_d; +}; +``` + +### BFS Traversal Condition +```cpp +[&](vertex_t const& src, // source + vertex_t const& dst, // destination + edge_t const& edge, // edge + weight_t const& weight // weight + ) { + // If the neighbor is not visited, update the distance. Returning false + // here means that the neighbor is not added to the output frontier, and + // instead an invalid vertex is added in its place. These invalides (-1 in + // most cases) can be removed using a filter operator or uniquify. + if (distances[dst] != std::numeric_limits::max()) + return false; + else + return (atomic::cas( + &distances[dst], std::numeric_limits::max(), + iteration + 1) == std::numeric_limits::max(), m_locks[dst]); +}; +``` ## Quick Start Guide Before building this project, make sure your system/compiler supports **C++20** and **cmake**.