System.Linq.Parallel Is Now Open Source

https://github.com/dotnet/corefx/tree/master/src/System.Linq.Parallel

by fekberg • 12 years ago

146 59 12 years ago

pekk• 12 years ago

I guess that's useful for people who are already bought in to the .NET world, but isn't LINQ encumbered by patents that pose a risk to anyone building on top of it?

uniformlyrandom• 12 years ago

The part that has been opensourced is under MIT license.

According to the wiki (http://en.wikipedia.org/wiki/MIT_License),

Whether or not a court might imply a patent grant under the MIT license therefore remains an open question.

This probably means MSFT is unlikely to enforce those patents.

filmor• 12 years ago

Microsoft is explicit about not doing that: https://github.com/dotnet/corefx/blob/master/PATENTS.TXT

However, as far as I understand it, the patent grant only holds for .NET runtimes you write yourself or programs to be run in a .NET runtime.

Rapzid• 12 years ago

Which, TBH, is all anyone should really care about. We can use dotnet for free if we like and it's getting officially open-sourced and supported across platforms; this is great.

-Not directing anything at you specifically

fotcorn• 12 years ago

Interesting that the patent grant from Microsoft is much more sane than that from Facebook:

https://github.com/dotnet/corefx/blob/master/PATENTS.TXT :

If you file, maintain, or voluntarily participate in any claim in a lawsuit alleging direct or contributory patent infringement by any Covered Code, or inducement of patent infringement by any Covered Code, then your rights under this promise will automatically terminate.

https://github.com/facebook/react/blob/master/PATENTS :

The license granted hereunder will terminate, automatically and without notice, for anyone that makes any claim (including by filing any lawsuit, assertion or other action) alleging (a) direct, indirect, or contributory infringement or inducement to infringe any patent: (i) by Facebook or any of its subsidiaries or affiliates, whether or not such claim is related to the Software, (ii) by any party if such claim arises in whole or in part from any software, product or service of Facebook or any of its subsidiaries or affiliates, whether or not such claim is related to the Software, or (iii) by any party relating to the Software; or (b) that any right in any patent claim of Facebook is invalid or unenforceable.

useerup2• 12 years ago

No. That was/is just FSF FUD.

You have always been able to build anything on top of it without concerns about patents from the implementation. This claim was so hilarious that it is incomprehensible that anyone ever believed it.

You have also been able to reimplement .NET CLR and core libraries without fear of patent litigation (from Microsoft). They have placed the CLR and core libraries under the legal estoppel of the community promise since 2007 (IIRC), in addition to publicly granting patent license to anyone creating an implementation of NET CLR and core libraries from the specifications. This latter was part of the process under which C#, .NET CLR and core libraries was standardized under ISO. A precondition for the standardization was that any necessary patents (for implementation) be offered on RAND terms (reasonable and non-discriminatory). Microsoft has always offered the patent grants free.

The community promise was created in response to FUD from (among others) FSF that Microsoft would just sue anyway (despite patent grants), and with their vast army of lawyers and deep coffers they could bury in court. The community promise creates legal estoppel, whereby a case by Microsoft would be dismissed if you acted "in good faith" by relying on the promise.

Open sourcing Parallel LINQ has no bearing on the patent status of anything building on top of it. If you believe the FSF FUD, you will be ensnared in .NET technology and Microsoft will sue you out of existence if you ever become successful. If you do not believe the FUD, you can continue to take advantage of LINQ, Parallel LINQ, .NET, C#, F# etc.

MichaelGG2• 12 years ago

When I read the community promise, it seemed to still allow Microsoft to go after competitors and use patents "defensively". So it's not impossible that you end up fighting MS on an unrelated matter, then they could use their promised patents against you. Probably incredibly unlikely, but a strict interpretation might view it as a risk.

Or did I misunderstand?

makomk• 12 years ago

No, it's not just FUD, and it doesn't just apply to LINQ either. Microsoft only promised not to sue over certain kinds of patent infringement in core libraries; that promise didn't extend to code you wrote on top of those libraries, which is unsurprising. Unfortunately they've patented a bunch of common ways of using .NET functionality, including many of the things you might use LINQ for and one of the most common idioms for using delegagtes and events. (Both of the commonly used GUI libraries - Windows.Forms and Gtk# - infringe the latter patent. So if you're running a GUI-based .NET app on anything but Windows then Microsoft can sue you if they ever decide it's to their advantage to do so.)

NKCSS• 12 years ago

Hmm, I wonder why this was added:

    #if DEBUG
                    currentKey = unchecked((int)0xdeadbeef);
    #endif

https://github.com/dotnet/corefx/blob/master/src/System.Linq... line 110 :P

Demiurge3• 12 years ago

looks like a marker to see if the code got past two previous lines?

gbvb• 12 years ago

It seems to be to avoid using currentKey inadvertently. If someone refers it elsewhere they get deadbeef.

Someone• 12 years ago

It is a magic marker http://en.wikipedia.org/wiki/Magic_number_%28programming%29#....

Both its 16-bit parts have odd values, it is an illegal address (at least on the systems it was introduced for), and it is recognizable in hex dumps. That makes it a good value for uninitialized memory.

blubbi2• 12 years ago

Sorry to be "that guy", but what is System.Linq.Parallel? Can anyone provide a brief description/ list of links where to read more about it? Why is open sourcing it such a big deal?

useerup2• 12 years ago

http://msdn.microsoft.com/en-us/library/dd460688(v=vs.110).a...

Parallel LINQ is an extension to LINQ (Language Integrated Querying). The "parallel" hints that it is a way to process results in parallel - using multiple threads, possibly on multiple CPUs/cores.

It allows you to express patterns like fork/join in a very elegant, fluent way.

If I have a set of Orders each with a collection of OrderItems, and each OrderItem* has a Consolidate method (I know, contrived, but bear with me).

    Orders.SelectMany(o => o.OrderItems).AsParallel().ForAll(Consolidate);

will "consolidate" all of the order items in parallel (or with the optimal degree of parallelism given CPUs/cores).

ultimape• 12 years ago

Linq is a library that injects a whole bunch functional style operations on top of list-like objects. Technically speaking, its implementing a type-safe query (think SQL) language on top of them, but the difference is very minimal in practice.

What this does is allow for certain operations to automatically be run in parallel. If you wanted to add 1 to every element in an array, you could do that with with Linq:

    IEnumerable<int> numbers = new List<int>() { 1, 2, 3, 4, 5 };
    var newList = from num in numbers.AsParallel()
                    select (x => x+1);

but by adding ".asParallel()" to the chain:

    var newList = from num in numbers.AsParallel()
                    select (x => x+1);

your code is automatically run on each element in a parallel fashion and the runtime handles marshalling it all into a queue for processing... or however it does it's magic.

The MSDN document on the way it does it is quite clear: http://msdn.microsoft.com/en-us/library/dd997399(v=vs.110).a... - describing many linq operations as 'delightfully parallel'.

I personally love Linq. To me it feels like using a Functional Relational Mapping system when combined with Linq-To-SQL, and the same semantics can be used to create a reactive programming model similar to what is intended with kefir.js and Akka ( http://msdn.microsoft.com/en-us/data/gg577609.aspx )

The idea itself isn't new, Perl 6 has something like this planned for trivial cases like for (1..10) { $_ = $_ +1; }

----

I don't know the full story, but for me the significance of open sourcing this code is that it will potentially encourage forks and extensions that allow running stuff upon GPGPUs or other massively parallel architectures while still using Linq style syntax.

TL;DR: With Linq, Anything that implements iEnumerable (lists, arrays, streams, etc) can be made to automatically support all sorts of nifty transforms. The Parallel bits let many of them run in parallel quite trivially

mattmanser2• 12 years ago

I hate to be nit-picky, what you're presenting is non-idiomatic C#, I would guess you're not a C# programmer. No-one really uses the SQL-esque langugage. The simple methods reads better, are quicker to type, are clearer and are more succinct. 'p', 'q' also tends to be the de facto standard operator in lambda expressions, rather than 'x', 'y' or 'i', 'j'. And why would you use IEnumerable<int> where you used it, it makes no sense?

Your code should have read:

    var numbers = new List<int>() { 1, 2, 3, 4, 5 };
    var newList = numbers.AsParallel().Select(p => p + 1);

CmonDev6• 12 years ago

LINQ = Enumeration Monad

Parallel = executes tasks on multiple cores simultaneously if possible

Quequau• 12 years ago

This is actually becoming my chief complaint about submissions. It appears to me as if folks now believe that it's cool to submit links which resolve as deeply and closely as possible to subject (in this case a the subdirectory inside the project's repo) with total disregard to the fact that there is insufficient (or no) information describing why we should be interested in the link or what, if anything, we should discuss.

I'm willing to bet the submitter went through a series of links beginning with some sort of announcement that something changed to get to the link they submitted. Why do folks think that we would not also benefit from that information or that it would not help to foster more interesting discussion?

protomyth• 12 years ago

Why? Probably because the "blog spam" or "only submit the original source" comments will show up and submissions get flagged. Happens enough that I would imagine the submitter probably followed all the links in response to prior submissions.

untog• 12 years ago

It would be better if we could change titles, but more often than not mods revert them back to whatever the page title is.

Demiurge3• 12 years ago

would be awesome if any of the dotnet open sourcing would allow to port linq to python. i would use it in a hearbeat.

CmonDev6• 12 years ago

There is more than one Python for .NET AFAIK. And an awesome VS support as well: https://pytools.codeplex.com

Demiurge3• 12 years ago

I can't use Python on .NET, I use it with numpy and the rest of the great native ecosystem. There are great ORMs, but I also really like LINQ.

QuadDamaged• 12 years ago

As far as I am concerned, all of the BCL has pretty much been 'open source' since Reflector came around in 200..2?

rjbwork• 12 years ago

There's a big BIG difference between "source readable" and "open source".

MichaelGG2• 12 years ago

By that logic, essentially every binary is open source. After all, you can dump a listing for any binary. And decompilers will create C source code (though it isn't always compilable). It's much different to getting the local var names, comments, actual source structure.

CmonDev6• 12 years ago

No, you still have to deliberately decompile it. JavaScript web sites on the other hand are always open-source (readable with a standard browser).

TheCoreh• 12 years ago

Having access to the source code doesn't mean it's "open source". Open source has to do with being able to reuse the code yourself, not to being able to read it.

mhaymo• 12 years ago

Can anyone knowledgeable tell us how this compares to Java's parallel streams?

kasey_junk• 12 years ago

LINQ/PLINQ are the obvious inspirations for Java 8s stream API. I don't know if they are exactly functionally equivalent but streams bring declarative style programming to Java iterable collections that C# has had for years.

But, don't be confused by the .NET Rx libraries which provide LINQ style methods to observable event streams and have been ported as RxJava. Personally, I think that is a better use of the term streams and find the Java 8 standard streams name confusing.

System.Linq.Parallel Is Now Open Source

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