apltail: From APL to Typed Array Programs

apltail is a compiler for a subset of APL, built around TAIL, a typed array intermediate language. It turns compact APL expressions into explicit array computations that can be inspected, interpreted, and compiled to C. The repository includes examples ranging from simple reductions to signal processing and matrix multiplication.

The foundations are described in my post on Compiling a Subset of APL Into a Typed Intermediate Language. Later work takes the next step towards GPUs: the post on APL on GPUs: A TAIL from the Past, Scribbled in Futhark explains how translating TAIL to Futhark lets the compiler turn high-level array operations into efficient parallel programs.

For a demonstration, see my presentation APL on GPUs – A Progress Report with a Touch of Machine Learning at Dyalog ‘17 in Elsinore, Denmark. It follows the APL–TAIL–Futhark tool chain through to GPU execution, including training a neural network to recognise handwritten digits. The presentation slides (PDF) are also available.