Scalapack

What it is:

• a set of libraries for dense linear algebra
• public domain
• based on Lapack, PBLAS, BLACS, (usually) MPI
• based on message passing paradigm
• using block-cyclically distributed matrices

  

• fast, scalable

What it isn't:

• easy to get for HP-UX
• easy to use, due to many parameters
• well documented, at least the many auxiliary routines