FlashX tools

FlashX provides three tools:

• utils/SAFS-util: helps users to access files in SAFS.
• matrix/utils/el2fg: constructs a FlashGraph graph from the text edge list.
• matrix/utils/fg2fm: constructs a FlashMatrix sparse matrix from a FlashGraph graph.

Interact with SAFS

utils/SAFS-util is a tool provided by SAFS that helps users to interact with SAFS. It provides a set of commands to access SAFS.

SAFS-util conf_file command ...
The supported commands are
	create file_name size: create a file with the specified size
	delete file_name: delete a file
	help: print the help info
	list: list existing files in SAFS
	load file_name [ext_file]: load data to the file
	load_part file_name ext_file part_id: load part of the file to SAFS
	verify file_name [ext_file]: verify data in the file
	export file_name ext_file: export an SAFS file to Linux filesystem
	info file_name: show the information of an SAFS file
	rename file_name new_name: rename an SAFS file

The most useful commands are:

• create: create an SAFS file with the specified size
• delete: delete an SAFS file
• list: list all files in SAFS
• load: load data to a SAFS file named file_name. Users can load data from a Linux file to the SAFS file by providing a second argument. If a Linux file isn't provided, the SAFS file is filled with 0.
• export: export an SAFS file to Linux filesystem
• info file_name: show the metadata information of an SAFS file
• rename file_name new_name: rename an SAFS file

Construct FlashGraph graphs

matrix/utils/el2fg takes a file 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. el2fg takes a FlashX configuration file, a text edge list file and a graph name, and outputs two files: graph_name.adj, which contains the adjacency lists of the graph, and graph_name.index, which contains the locations of the adjacency lists in the graph file. By default, el2fg keeps all intermediate data in memory.

matrix/utils/el2fg [options] conf_file edge_file graph_name
-u: undirected graph
-U: unqiue edges
-e: use external memory
-s size: sort buffer size
-g size: groupby buffer size
-t type: the edge attribute type

The most important flags are shown as follows:

• -u: To construct an undirected graph, users have to explicitly enable this flag.
• -U: enable this flag to remove redundant edges in a graph.
• -e: enable this flag to use disks to construct a graph. It requires users to configure SAFS correctly.
• -t type: users can specify the edge attribute type. When this option is specified, the input edge list has to have three columns and the third column provides the edge attribute. Currently, four attribute types are supported. "I": 32-bit integer attributes, "L": 64-bit integer attributes, "F": single-precision float-point, "D": double-precision float-point.

An example:

To convert a directed graph wiki-Vote in the edge list format to the FlashGraph format, we can run the following command: matrix/utils/el2fg matrix/conf/run_test.txt wiki-Vote.txt wiki-Vote This converts an edge list in wiki-Vote.txt to the FlashGraph format and generate two files: wiki-Vote.adj and wiki-Vote.index.

To convert an undirected graph facebook in the edge list format to the FlashGraph format, we run: matrix/utils/el2fg matrix/conf/run_test.txt -u facebook_combined.txt facebook

Construct FlashMatrix sparse matrices

matrix/utils/fg2fm converts a graph in the FlashGraph format to a sparse matrix in the FlashMatrix format. The FlashMatrix is necessary to support very efficient sparse matrix dense matrix multiplication (SpMM). SpMM is much more efficient with the FlashMatrix format than the FlashGraph format.

fg2fm [options] conf_file graph_file index_file matrix_name
-h height: the height of a 2D-partitioned matrix block
-w width: the width of a 2D-partitioned matrix block
-v: verify the generated matrix image
-g size: the groupby buffer size on vector vectors
-t type: the type of non-zero entries

Users don't need to provide the options to fg2fm most of time. The only useful option for some users is -t, which tells fg2fm the type of the edge attribute in the FlashGraph format.

fg2fm detects whether the provided graph is directed. For an undirected graph, it outputs two files: matrix_name.mat, which contains the sparse matrix data, and matrix_name.mat_idx, which contains the locations of some rows of the sparse matrix in matrix_name.mat. For a directed graph, it outputs four files: matrix_name.mat, matrix_name.mat_idx, matrix_name_t.mat and matrix_name_t.mat_idx. The first two files contain the sparse matrix and the last two files contain the transpose of the sparse matrix.