hegg-0.3.0.0: Fast equality saturation in Haskell
Safe HaskellSafe-Inferred
LanguageHaskell2010

Data.Equality.Saturation.Scheduler

Description

Definition of Scheduler as a way to control application of rewrite rules.

The BackoffScheduler is a scheduler which implements exponential rule backoff and is used by default in equalitySaturation

Synopsis

Documentation

class Scheduler s where Source #

A Scheduler determines whether a certain rewrite rule is banned from being used based on statistics it defines and collects on applied rewrite rules.

Associated Types

data Stat s Source #

Methods

updateStats Source #

Arguments

:: s

The scheduler itself

-> Int

Iteration we're in

-> Int

Index of rewrite rule we're updating

-> Maybe (Stat s)

Current stat for this rewrite rule (we already got it so no point in doing a lookup again)

-> IntMap (Stat s)

The current stats map

-> [Match]

The list of matches resulting from matching this rewrite rule

-> IntMap (Stat s)

The updated map with new stats

Scheduler: update stats

isBanned Source #

Arguments

:: Int

Iteration we're in

-> Stat s

Stats for the rewrite rule

-> Bool

Whether the rule should be applied or not

data BackoffScheduler Source #

A Scheduler that implements exponentional rule backoff.

For each rewrite, there exists a configurable initial match limit. If a rewrite search yield more than this limit, then we ban this rule for number of iterations, double its limit, and double the time it will be banned next time.

This seems effective at preventing explosive rules like associativity from taking an unfair amount of resources.

Originaly in egg

Constructors

BackoffScheduler 

Fields

defaultBackoffScheduler :: BackoffScheduler Source #

The default BackoffScheduler.

The match limit is set to 1000 and the ban length is set to 10.