First steps#

The idea is to follow along with the evolution of the CMakelists.txt file, the history of which is here.

Note that though the evolution of the CMakeLists is used, the conversion itself follows the Makefile, along with the regex functions defined in this library.

Broadly speaking this proceeds along the following path:

  1. [x] Hardcode some of the default config generation mechanism (port them later)

  • f_check and c_check

  • prebuild and system

  1. [ ] Port the interface

  2. [ ] driver/level2

  3. [ ] driver/level3

  4. [ ] driver/others

  5. [ ] kernel, which will need to dynamically choose the right one

  6. [ ] Optionally construct and add lapacke and the other bells and whistles

Essentially means steps 1 through 5 can be broken down into the following:

  • Interfaces :: Primarily contains wrapper functions for BLAS API calls for interfacing with higher-level BLAS functions but do not contain the computational kernels themselves.

  • Drivers :: Include some optimized implementations for Level 2 and Level 3 BLAS operations, such as matrix-vector and matrix-matrix multiplications. These still rely on lower-level kernels for the actual computations.

  • Kernels: This is where the core computational kernels reside. These kernels are highly optimized for specific architectures and perform the low-level arithmetic operations called by higher-level functions.

Of course, OpenBLAS includes lapack as well, but that is a later concern.

Architectures#

The way OpenBLAS is meant to run optimizations depends on processor families, e.g. HASWELL or SANDYBRIDGE. Typically this means that the “nearest” architecture might be used as a starting point for even more optimizations.