BLACS

The BLACS (Basic Linear Algebra Communication Subprograms) project is an ongoing investigation whose purpose is to create a linear algebra oriented message passing interface that may be implemented efficiently and uniformly across a large range of distributed memory platforms.

The length of time required to implement efficient distributed memory algorithms makes it impractical to rewrite programs for every new parallel machine. The BLACS exist in order to make linear algebra applications both easier to program and more portable. It is for this reason that the BLACS are used as the communication layer of ScaLAPACK. Key ideas in the BLACS include:

• Standard interface,
• Process grid and scoped operations,
• Contexts,
• Array-based communication,
• ID-less communication.

Other options are:

• Reference to BLACS routines.
• BLACS example routines.
• Discussion on BLACS topology.
• Downloading code/papers.

The General in this project is Jack Dongarra; the man in the trenches is R. Clint Whaley. Questions about the BLACS should be mailed to