Tech talk: From Haskell to Hardware via CCCs

  • Date Tuesday, April 07, 2015  Time 11:00 AM
  • Speaker Conal Elliott
  • Location Galois, 421 SW 6th Ave. Suite 300, Portland, OR, USA (3rd floor of the Commonwealth building)
  • Galois is pleased to host the following tech talk. These talks are open to the interested public--please join us! (There is no need to pre-register for the talk.)

For the last several years, speed improvements in computing come mainly from increasing parallelism. Imperative programming, however, makes parallelization very difficult due to the many possible dependencies implied by effects. For decades, pure functional programming has held the promise of parallel execution while retaining the very simple semantics that enables practical, rigorous reasoning. This talk describes a prototype compiler from Haskell (not a library) to low-level hardware descriptions for massively parallel execution on reprogrammable logic devices. The compiler works by monomorphizing, miscellaneous other transformations, and conversion to the vocabulary of cartesian closed categories (CCCs), as captured in a small collection of Haskell type classes. One instance of those classes provides an interpretation as parallel circuits. I will show many examples of simple Haskell programs and corresponding compiler-generated circuits.

Conal Elliott has been working (and playing) in functional programming for more than 30 years. He especially enjoys applying semantic elegance and rigor to library design and optimized implementation. He invented the paradigm now known as “functional reactive programming” in the early 1990s, and then pioneered compilation techniques for high-performance, high-level embedded domain-specific languages, with applications including 2D and 3D computer graphics. The latter work included the first compilation of Haskell programs to GPU code, while maintaining precise and simple semantics and powerful composability, as well a high degree of optimization. Conal earned a BA in math with honors from the College of Creative Studies at UC Santa Barbara in 1982 and a PhD in Computer Science from Carnegie Mellon University in 1990. His latest position was at Tabula Inc, where he worked on chip specification and compiling Haskell to hardware for massively parallel execution until their closure in early 2015. Before Tabula, his positions included Architect at Sun Microsystems and Researcher in the Microsoft Research graphics group. He has also coached couples and led conscious relationship workshops together with his partner Holly Croydon, with whom he now lives on 20 acres in the woods in the California Gold Country. For publications, CV, professional blog, etc, see

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