The speculation package

[Tags:bsd3, library]

A framework for safe, programmable, speculative parallelism, loosely based on

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Versions 0.0.0, 0.0.1, 0.0.2, 0.1.0, 0.2.0, 0.3.0, 0.4.0, 0.5.0, 0.5.1, 0.6.0, 0.7.0, 0.8.0,,,,,,,,,,, 1.3, 1.4, 1.4.1,,, 1.5,,,
Dependencies array (>=0.2 && <0.4), base (>=4 && <6), containers (>=, parallel (==2.2.*) [details]
License BSD3
Copyright (c) 2010 Edward A. Kmett
Author Edward A. Kmett
Maintainer Edward A. Kmett <>
Category Concurrency
Home page
Uploaded Sun Jun 27 07:45:35 UTC 2010 by EdwardKmett
Distributions LTSHaskell:, NixOS:, Stackage:, Tumbleweed:
Downloads 6270 total (18 in the last 30 days)
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Status Docs uploaded by user
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Readme for speculation

Readme for speculation-0.0.1


Speculative evaluation primitives for Haskell, very loosely based on the paper "Safe Programmable Speculative Parallelism" by Prabhu, Ramalingam, and Vaswani.


spec :: Eq a => a -> (a -> b) -> a -> b

spec takes three arguments: An initial guess as to what the argument to the function will be when it is evaluated, a function to evaluate, and the actual argument to the function.

Spec checks to see if its actual argument has been evaluated, if so it just applies the function to the argument.

Otherwise, it begins evaluating the function with the guessed argument in parallel with evaluating the argument.

If you guessed right, then the result of applying the function to your guess is returned.

Otherwise, it then evaluates the function with the correct argument.

If a good guess is available, this permits us to increase parallelism in the resulting program.

It is subject to the following identity:

spec a f a = a `seq` f a 

speculative folds

A number of speculative folds are also provided via the Speculative class.

These take an extra argument which is a function that guesses the result of of the fold up to a given point.

A minimal definition for Speculative can be derived automatically for any Foldable container.