Simon Marlow
Parallel and Concurrent
Programming in Haskell
Downloa d f r o m W o w ! e B o o k < w w w.woweb o o k . c o m >
Parallel and Concurrent Programming in Haskell
by Simon Marlow
Copyright © 2013 Simon Marlow. All rights reserved.
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July 2013:
First Edition
Revision History for the First Edition:
2013-07-10: First release
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ISBN: 978-1-449-33594-6
[LSI]
Table of Contents
Preface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix
1.
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Terminology: Parallelism and Concurrency 2
Tools and Resources 3
Sample Code 4
Part I. Parallel Haskell
2.
Basic Parallelism: The Eval Monad. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Lazy Evaluation and Weak Head Normal Form 9
The Eval Monad, rpar, and rseq 15
Example: Parallelizing a Sudoku Solver 19
Deepseq 29
3.
Evaluation Strategies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Parameterized Strategies 32
A Strategy for Evaluating a List in Parallel 34
Example: The K-Means Problem 35
Parallelizing K-Means 40
Performance and Analysis 42
Visualizing Spark Activity 46
Granularity 47
GC’d Sparks and Speculative Parallelism 48
Parallelizing Lazy Streams with parBuffer 51
Chunking Strategies 54
The Identity Property 55
4. Dataflow Parallelism: The Par Monad. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
iii
