FlashX tools

Interact with SAFS

Convert graph format

el2al takes a file or multiple files of edge lists in the text format and converts them to the FlashGraph format, which is adjacency list in the binary format. The edge list file(s) can be gzip'd. The gzip'd file needs to have a filename extension .gz in order to be considered as a gzip'd file. el2al generates two binary files: a graph file that contains the adjacency lists of the graph and an index file that contains the locations of vertices in the graph file. By default, el2al keeps all intermediate data in memory.

el2al [options] adj_list_file index_file edge_list_files (or directories)

• -u: undirected graph
• -v: verify the created adjacency list
• -t type: the type of edge data. Supported type: count, timestamp,
• -m: merge multiple edge lists into a single graph.
• -w: write the graph to a file
• -T: the number of threads to process in parallel
• -d: store intermediate data on disks

An example:

To convert a directed graph in the edge list format to the FlashGraph format, we can run the following command:

flash-graph/tools/el2al -w wiki-Vote.adj wiki-Vote.index wiki-Vote.txt

This converts an edge list in wiki-Vote.txt to the FlashGraph format and generate two files: wiki-Vote.adj-v4 and wiki-Vote.index-v4. wiki-Vote.adj-v4 contains the graph data and wiki-Vote.index-v4 contains the index to the graph data.

To convert an undirected graph in the edge list format to the FlashGraph format, we run:

flash-graph/tools/el2al -w -u facebook.adj facebook.index facebook_combined.txt

When converting a large graph, el2al uses a lot of memory if it keeps all intermediate data in memory, and takes a long time to convert a graph. el2al can keep intermediate data on disks and run in parallel. When -d flag is used, el2al uses stxxl to store intermediate data on disks. Note: users may need to create .stxxl in the current directory to configure the stxxl library where running el2al with -d flag. The page describes how to configure stxxl. -T flag specifies the number of threads used for graph format conversion.

For example, the following command converts a twitter graph with around 60 million vertices in the text edge list format to the adjacency list format out of core and in parallel.

el2al -w -T 32 -d twitter.adj twitter.index twitter_rv.net.gz

FlashGraph configuration parameters

FIXME