As a collection of test problems becomes large and diverse it becomes increasingly important to have effective tools for finding problems which have particular characteristics of interest. For sparse matrices, these might be things like symmetry, size, and percentage of nonzeros. The Harwell-Boeing exchange format includes a variety of such information; unfortunately, the distribution of this information inside large files of matrix elements makes it difficult to use for efficient searching. In addition, a large variety of additional useful data has only been accessible in printed reports. To allow efficient automation of matrix search and retrieval it is necessary to represent all of this information in a concise and well-defined format.
Our philosophy is to maintain a single central base of meta-data describing the matrix collection in a neutral format. This database should be rich enough to build a variety of applications, such as
The Matrix Market meta-database consists of two files, one describing properties of individual matrices (the Matrix database) and a second describing properties of sets of matrices (the Set database). Each contains a sequence of multi-line records delimited by a blank line (i.e., two successive newline characters). Each record contains a list of attribute-value pairs. Each attribute name starts at the beginning of a line, followed by a TAB character, and its value. A value may be continued onto successive lines by placing a TAB as the first character on each additional line. Attributes may appear in any order.
Many of the attributes represented in the database correspond to information provided in the Harwell-Boeing report (Duff, Grimes and Lewis, 1989). Table 1 lists the attributes currently represented in the Matrix database; Figure 1 provides an example entry. For attributes and an example of the Set database, see Table 2 and Figure 2, respectively.
Figure: Sample entry from the Matrix database.
Table: Attributes in the Matrix database
Table: Attributes in the Set database
Figure: Sample entry from the Set database.