Computationswhere

Computationswhere is a term used in theoretical discussions of computational models to denote a class of computations defined by where-conditions or location-based predicates. In this framing, program execution is guided by constraints that restrict application of rules to subdomains of the input state or environment, rather than by control flow alone.

Formally, a computationswhere model consists of a set of transformation rules paired with where-clauses. A rule is applicable only if its where-clause evaluates to true under the current state. When applied, the rule's transformation is carried out within the portion of the state allowed by the clause, producing a new state and potentially enabling further matches elsewhere.

The notion draws connections with guarded or conditional evaluation, constraint programming, and dataflow paradigms. It emphasizes locality: computation may proceed in parallel on independent regions that satisfy their own where-conditions, while interactions occur only through defined interfaces or shared constraints.

Examples in discussions include localized data processing where filtering is restricted to items with particular spatial coordinates, decentralized query execution in distributed databases under region constraints, and partial evaluation of programs whose unfoldings are constrained to certain input features or environments.

As a term, computationswhere is not widely standardized and appears chiefly in exploratory or speculative writing about locality-aware computation. It is typically treated as a conceptual framework rather than a formal, widely implemented model, used to illustrate how predicates about location or context can shape computation.

See also: constraint programming, guarded commands, dataflow programming, locality in computing, distributed databases.