This virtual class represents a reduction, an actor that transforms a problem into an equivalent problem. By equivalent, we mean that there exists a mapping between solutions of either problem: if we reduce a problem \(A\) to another problem \(B\) and then proceed to find a solution to \(B\), we can convert it to a solution of \(A\) with at most a moderate amount of effort.

# S4 method for Reduction,Problem
accepts(object, problem)

# S4 method for Reduction

# S4 method for Reduction,Solution
retrieve(object, solution)

# S4 method for Reduction,Problem
perform(object, problem)

# S4 method for Reduction,Solution,list
invert(object, solution, inverse_data)



A Reduction object.


A Problem object.


A Solution to a problem that generated the inverse data.


The data encoding the original problem.


Every reduction supports three methods: accepts, perform, and invert. The accepts method of a particular reduction codifies the types of problems that it is applicable to, the perform method takes a problem and reduces it to a (new) equivalent form, and the invert method maps solutions from reduced-to problems to their problems of provenance.

Methods (by generic)

  • accepts(object = Reduction, problem = Problem): States whether the reduction accepts a problem.

  • reduce(Reduction): Reduces the owned problem to an equivalent problem.

  • retrieve(object = Reduction, solution = Solution): Retrieves a solution to the owned problem.

  • perform(object = Reduction, problem = Problem): Performs the reduction on a problem and returns an equivalent problem.

  • invert(object = Reduction, solution = Solution, inverse_data = list): Returns a solution to the original problem given the inverse data.