CHACO <version>2.0 <title_line>software for partitioning and ordering graphs <author>Bruce Hendrickson (bahendr@cs.sandia.gov) Rob Leland (leland@cs.sandia.gov) <abstract>Chaco contains a variety of partitioning algorithms including spectral bisection, quadrisection and octasection, the inertial method, the Kernighan-Lin/Fiduccia-Mattheyses algorithm and multilevel partitioners. Advanced techniques that are new to version 2.0 include terminal propagation (a method for improving data locality adapted from the circuit community), the ability to map partitions intelligently to hypercube and mesh architectures, and easy access to the Fiedler vector to assist the development of new applications of spectral graph algorithms. This capability has already been used in applications ranging from gene sequencing to database design. A user's guide and papers describing the algorithms are available by anonymous ftp to cs.sandia.gov in the directory pub/tech_reports/bahendr. Academic user's can obtain the code at no charge under a research license agreement and it may also be licensed for commercial application. <contact>Bruce Hendrickson (bah@cs.sandia.gov) <category>numerical <keywords>data partitioning; unstructured grid </urc>