mealy
Mealy machines for processing time-series and ordered data.
https://github.com/tonyday567/mealy#readme
| LTS Haskell 24.28: | 0.5.1.1 |
| Stackage Nightly 2026-01-13: | 0.5.1.1 |
| Latest on Hackage: | 0.5.1.1 |
Maintained by [email protected]
This version can be pinned in stack with:
mealy-0.5.1.1@sha256:97b6608923bce7008997b8a8ec473cb44466d307a04ce0be50f8b3bb7e955f13,2052Module documentation for 0.5.1.1
Depends on 13 packages(full list with versions):
mealy
A ‘Mealy’ is a triple of functions
- (a -> b) inject: Convert (initial) input into the (initial) state type.
- (b -> a -> b) step: Update state given prior state and (new) input.
- (c -> b) extract: Convert state to the output type.
A sum, for example, looks like M id (+) id where the first id is the initial injection and the second id is the covariant extraction.
This library provides support for computing statistics (such as an average or a standard deviation) as current state within a mealy context.
Usage
Usage is to supply a decay function representing the relative weights of recent values versus older ones, in the manner of exponentially-weighted averages. The library attempts to be polymorphic in the statistic which can be combined in applicative style.
import Prelude
import Data.Mealy
fold ((,) <$> ma 0.9 <*> std 0.9) [1..100::Double]
(91.00265621044142,9.472822805289121)