There are almost as many graph file formats as there are graph processing platforms. Here, I attempt to provide a comprehensive listing. Some of these are nearly trivial, but yet, the standards are just not established. Whether the vertices are 0-indexed or 1-indexed is undefined. However, this does matter for some systems such as GraphMat. All the examples show the same directed, unweighted graph with the exception of .metis
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This is the "edge list" format. The format is one edge per line of the form . For example,
1 2
2 1
1 3