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New Post: Parallel Programming with Microsoft .NET 2nd Edition?

AdeMiller — Tue, 27 Dec 2011 11:25:58 GMT

Right now we don't have any plans to do another edition based on the Rx although I have considered doing another additional suppliment to cover the new additions in .NET 4.5; the dataflow and async extensions.

Ade

New Post: ParallelQuickSort fails with zeros array

AdeMiller — Tue, 27 Dec 2011 11:23:26 GMT

Hi Lionel,

I can repro your problem for large arrays of zeros. QuickSort, the algorithm used here, is known to perform very poorly for arrays containing only a few duplicated values. See:

http://www.angelfire.com/pq/jamesbarbetti/articles/sorting/001_QuicksortIsBroken.htm

http://algs4.cs.princeton.edu/23quicksort/

In this case it scales as order N*N. So I'm not sure that it hangs but it does run very slowly. My experiments show it to be running and making progress.

Ade

New Post: ParallelQuickSort fails with zeros array

LKeene — Wed, 21 Dec 2011 19:55:50 GMT

Hello, I was delighted to find this material on line. So far it's been very helpful. However, while trying out the Chapter 6 parallel quick sort, I found it got stuck in an infinite loop somewhere when I passed it an array of 0.0f. Ex:

Single array = new Single[1280 * 960]; // Initialized to 0.0f

ParallelSort(array);

Any ideas on how to fix this? Thanks in advance.

-L

New Post: Parallel Programming with Microsoft .NET 2nd Edition?

linuxbox — Mon, 11 Jul 2011 15:34:41 GMT

Any chance for a second edition of this book including the Rx (Reactive), TDF (TPL Dataflow), and async/await keywords?

New Post: question about LimitedConcurrencyTaskScheduler

sfun28 — Wed, 09 Mar 2011 20:28:22 GMT

Hi,

I'm using LimitedConcurrencyTaskScheduler via ParallelOptions.TaskScheduler and Parallel.For/ForEach. If I don't set the ParallelOptions .MaxDegreeOfParallelism, am I guaranteed to get X parallel executions where X =maxDegreeOfParallelism set in LimitedConcurrencyTaskScheduler constructor? Is it possible that any part of the code involved in this would use less than X threads? I'm looking for a solution to use Parallel.For/ForEach and guarantee that maxDegreeOfParallelism threads are used - no more, no less ( unless of course most of the tasks have been completed and there are less than X tasks left to process).

New Post: Updated Demo

AdeMiller — Tue, 11 Jan 2011 04:29:37 GMT

I've updated the Book Companion 1.0 drop to include the latest source code from the talk demo. This includes some minor updates/fixes to the code.

Various decks and videos of of the talk that goes with this demo are available online. See the following blog posts:

TechEd China Decks Online (Chinese deck)

Patterns of Parallel Programming at Oredev

Patterns of Parallel Programming – TechEd Talk Online (with video)

If you have an feedback on this or the other examples please create a discussion item here. Report bugs in the issue tracker.

New Post: Where's My Free Book?

AdeMiller — Sat, 18 Sep 2010 16:25:37 GMT

Hi David,

Sorry for the confusion, the MSDN Flash title is misleading. I've updated the homepage to make it clearer what's free and whats not. Unfortunately there isn't a free version in eBook format.

Ade

New Post: Where's My Free Book?

davidmjohnson83 — Fri, 17 Sep 2010 14:35:05 GMT

I just received the MSDN Flash Newsletter and it states to get a free ebook and then has this books title. But then you click on the link and its saying you have to purchase it. What's the deal?

Free E-book: Parallel Programming with Microsoft .NET

Learn design patterns for decomposition and coordination on multicore architectures. Includes samples in C#, VB and F#.

*UPDATE*

Nevermind, I found it http://msdn.microsoft.com/en-us/library/ff963553.aspx

Is there a way I can get the actual free ebook, so I can send it to my kindle?

Thanks,

David

New Post: F.Y.I. just one more typo.

Xantix — Sat, 04 Sep 2010 06:41:29 GMT

This typo is on page 123, from the third paragraph of Appendix A, in the first paragraph under Structural Patterns.

“Consider this tradeoff then applying these patterns. ”

Either changing “then” to when, or changing “applying” to apply, would correct the sentence.

I wish that I had been able to find these things before the book was published, but I didn’t learn of this book until the beginning of this Semester, exactly one week ago, for which we have been using this as reading material.

A wonderful book, I expect to finish reading the Appendixes soon.

--Xantix--

New Post: Feedback on drop 6: Chapter questions and answers

AdeMiller — Wed, 01 Sep 2010 15:58:55 GMT

Thanks Xantix,

I added a work item on this (http://parallelpatterns.codeplex.com/workitem/18653 ) and we'll probably update the answers doc as the book has now gone to print.

The printed book is now available for pre-order from O’Reilly

Parallel Programming with Microsoft® .NET

The eBook is also available for download (today) from O’Reilly and Safari Books Online. Expect to see it at your favorite book store real soon!

New Post: Feedback on drop 6: Chapter questions and answers

xantix — Wed, 01 Sep 2010 05:30:29 GMT

Chapter 2: Exercise 1 reads Which of the following problems *could* be solved using the parallel loop techniques taught in
this chapter?

Part e, "Counting the total number of occurrences of each word in a collection of text files," *could* be done as such.

Consider: Iterate through the text files and create a set containing each unique word in the files.

For each of these unique words

Perform a linear search through each file to count how many times it occurs.

The count of each word is stored in its own location, say at its specific index in an array.

In this algorithm the individual words are the parallel data, rather than the files being the parallel data. The files are read only and the accumulators are word specific, no two loops write to the same location.

For a set of files this algorithm with n distinct words will iterate through each file 1 + n times, but using n cores means the algorithm finishes in the time of 2 iterations of the files.

Note that there are sequential algorithms of solving this which require just one iteration, and using parallel aggregation that that one iteration can be gone through concurrently. The question was if it *could* be done, not if it was useful.

So you may want to change the question or the answer.

New Post: Drop 7 ParallelSort

AdeMiller — Thu, 12 Aug 2010 03:43:06 GMT

Thanks Mike,

I've opened issue 18466 to track this and will get it fixed soon.

Ade

New Post: Drop 7 TFS Bindings

AdeMiller — Thu, 12 Aug 2010 03:38:06 GMT

Thanks Mike,

I reopened issue 18432 and will get this fixed.

Ade

New Post: Drop 7 ParallelSort

mikequinlan — Mon, 09 Aug 2010 15:02:00 GMT

The README.txt file says "always uses the same random seed so runs are reproducible" but the code says

int seed = Environment.TickCount;

...
var a = MakeArray(length, seed);

New Post: Drop 7 TFS Bindings

mikequinlan — Mon, 09 Aug 2010 14:56:15 GMT

Drop 7 appears to still contain TFS bindings. When I attempt to open the project it asks for a userid/password for https://vstf-us-01.partners.extranet.microsoft.com:8443

New Post: Feedback on drop 6: Chapter questions and answers

AdeMiller — Fri, 09 Jul 2010 22:54:19 GMT

One of the things people asked for was questions at the end of each chapter. And, more importantly, for us to post answers to the questions. This drop includes a preliminary draft of the whole book with questions at the end of each chapter. We've also posted a document containing answers. While the book text is "done", we'd still like to hear feedback on the answers. Thanks, Ade

New Post: Feedback on Drop 3 (Preface and Chapters 1, 2 and 5)

AdeMiller — Fri, 09 Jul 2010 04:58:44 GMT

As you can see we've taken this feedback and a lot of other people's input on the title and come up with something that we feel better reflects the actual content and goals of the book.

Ade

New Post: Feedback on Drop 6 (Preface, Chapters, Appendices, etc.)

jon — Thu, 08 Jul 2010 22:46:56 GMT

Please use this discussion to give us feedback on the guide's Drop 6 (7/08/2010). It contains a preface, seven chapters, appendices, glossary, and references.

Preface

Chapter 1 - Introduction

Chapter 2 - Parallel Loops

Chapter 3 - Parallel Tasks

Chapter 4 - Parallel Aggregation

Chapter 5 - Futures

Chapter 6 - Dynamic Task Parallelism

Chapter 7 - Pipelines

Appendix A - Adapting Object-Oriented Patterns

Appendix B - Debugging and Profiling Parallel Applications

Appendix C - Technology Overview

Glossary

References

The preface will give you an idea of the overall table of contents.

Thanks,

Jon

New Post: Parallel.For

rrv — Sun, 04 Jul 2010 19:04:55 GMT

Thanks ReedCopsey,

I expected there was a way which could be beyond my knowledge. I understand the reason. So now i shall rebuild the enumeration in reverse and feed it to "Parallelism.For", process parallely, grind, bake, and give me bread out of it.

Out of curiosity !!! I thought Do-While and While-Wend are out of order loops while FOR loops are strictly ordered controlled by keyword "STEP". A sequential increasing order FOR loop just does'nt require an STEP keyword was my understanding. "FOR loop is processed out of order" just did not sell well with me but i will remember now onwards.

Thanks Reed for the explanation.

New Post: Parallel.For

ReedCopsey — Thu, 01 Jul 2010 20:17:17 GMT

RV, Typically, if you need to iterate a parallel loop in a specific order (ie: Step -1), then the loop body relies on state separate from the loop body itself. The fact that ordering is important means that it's unlikely a candidate to be executed in parallel, since running the loop using Parallel.For means that the items will be processed out of order (by definition). As such, there's no support in the framework for this. -Reed