Abstract

This talk presents latest developments on the Ypnos domain-specific language for programming stencil computations in Haskell. Stencil computations, which involve aggreagate operations over the elements of an array, are a common programming pattern in scientific computing, games, and image processing. Ypnos allows declarative, abstract specification of a stencil computation, exposing the structure of a problem to the compiler and to the programmer via specialised syntax called grid patterns. Ypnos has the safety invariant that well-typed programs cannot index outside of array boundaries. Thus correctness guarantees are provided and run-time bounds checking can be eliminated, improving performance. Program information is encoded in the types of Ypnos expressions, using advanced type-system features of the Glasgow Haskell Compiler. Safe-indexing in Ypnos is a decidable property and is enforced at compile time via type checking.

This is a 20-minute practice talk for the DSL 2011 conference.