Finding the Right BLAS

If you are seeing errors such as "undefined reference to 'cblas_daxpy'", it is because you don't have the right blas installed or DigitalMaterial cannot find it. Install one of the implementations described below and make sure the variable "BLAS_DIR" in the includes.mk file points to the right directory.

Some Implementations

• Intel BLAS for linux also known as ASCII-Red BLAS. This is the version of blas we have developed DigitalMaterial with and the only version we know for sure will work. It is free if you pledge to not use it for commercial purposes. It is not open source and requires rpm to install it. Since it is optimised for intel processors, it does not work particularly well on the Athlon. If you use intel blas, you will have to change -lblas to -lmkl in the includes.mk file.
• ATLAS Automatically Tuned Linear Algebra Software on Netlib. This is an open source alternative to the intel blas. You can compile it from source and try to optimise it for your architecture.

More Information

• BLAS Frequently Asked Questions
• The BLAS Technical Forum, also known as BLAST, is the official body working on BLAS specifications. If that link doesn't work, you can scan their archives on netlib.
• BLAS thread in Beowulf archives.
• Beowulf BLAS thread summary.
• single BLAS article at Duke's Brahma
• For questions about CBLAS, here is a proposed chapter on the C API to the legacy BLAS in (postscript, or pdf), culled from their netlib archive. If the BLAST technical forum is working, look there for more recent versions of these proposals.