A comprehensive Installation Guide for ScaLAPACK is provided. In short, a user only needs to modify one file, SLmake.inc, to specify his compiler, compiler flags, location of his MPI library, BLACS library, and BLAS library. And then type make lib to build the ScaLAPACK library, and make exe to build the testing/timing executables. Example SLmake.inc files for various architectures are supplied in the SCALAPACK/INSTALL subdirectory in the distribution. When you install ScaLAPACK, the installation assumes that the user has available a low-level message passing layer (like MPI, PVM, or a native message-passing library), a BLACS library (MPIBLACS or PVMBLACS, etc), and a BLAS library. If any of these required components is not available, then the user must build the needed component before proceeding with the ScaLAPACK installation. • MPI • PVM • BLACS • ATLAS or BLAS. If a vendor-optimized BLAS library is not available, ATLAS can be used to automatically generate an optimized BLAS librar