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2
votes
2answers
48 views

can a single SQL Server connection be shared among tasks executed in parallel

Can a single SQL Server connection be shared among tasks executing in parallel? Each task would dequeue an item from a ParallelQueue, instantiate a SqlClient command, and insert a row into the table. ...
10
votes
2answers
413 views

Why do programmers define programming models to replace C/POSIX for parallelism?

Providers of new computer architectures regularly try to introduce new programming models, e.g. recently CUDA/OpenCL for GPGPUs, and displace C/POSIX as the control interface to platform ...
6
votes
1answer
149 views

Querying large amount of data for parallel processing [closed]

I have a dataset containing list of users (around 50M). Each user has an email address, name, and some more data columns. I want to send a weekly email to those users, and the content of the email ...
5
votes
2answers
240 views

How to optimize/parallelize the following clustering/joining algorithm:

I have relatively-small algorithm that takes up ~60% of the total run-time of my scientific code (57 lines of 3600), so I would like to find a way to optimize what I'm doing and make the code ...
3
votes
3answers
164 views

Which scenarios to use .NET Concurrent Collections effectively?

I am investigating how to introduce parallelism into an application to improve performance. In particular, I am looking at parallel for loops and their variants and my initial experiments show ...
27
votes
5answers
2k views

What is it about functional programming that makes it inherently adapted to parallel execution? [duplicate]

I've been reading over and over that functional languages are ideal (or at least very often useful) for parallelism. Why is this? What core concepts and paradigms are typically employed and which ...
0
votes
0answers
38 views

Algorithm to minimize total processing time with multiple workers?

Say you have an office with 3 printers, all execute print jobs at exactly the same speed. Say you have a fixed order size of: 20 single page reports which take 10 seconds each 15 paper packets which ...
2
votes
0answers
61 views

What parallelization methods can make neural nets train faster?

A fairly straightforward way (on a theoretical level, at least) of parallelizing artifical neural networks (ANNs) would be to divy up the batches of training examples during every epoch so that ...
2
votes
2answers
67 views

Parallelising processing of users

Update I updated my question to reflect the fact I'm working with a database. I need to process user actions: The actions for each user change the user's balance which is then persisted to a ...
1
vote
0answers
51 views

Can't figure out how to parallelize the calculation of the amount of offspring expected for species in genetic algorithm

I developed a genetic algorithm in java 8 taking advantage of its reasonably free parallelism opportunities with Streams. As you are likely aware, running the epochs takes its time for even a test ...
1
vote
1answer
61 views

Matrix distribution to process grid

I need to write a program, which will perform LU-decomposition, etc. The problem is that I don't know about the preferred way to distribute the loaded matrix from the root process to other processes. ...
1
vote
0answers
93 views

What parallelism happens in a vector processor?

From Tanebaum's Structured Computer Organization A vector processor is very efficient at executing a sequence of operations on pairs of data elements. All of the operations are performed in a ...
3
votes
2answers
220 views

Strategy game, how do I calculate the parallel actions?

I am building a strategy game where multiple units(5 - 20) fighting each other. I have a game logic that calculate all the actions that been done on each turn, and send it to the game engine to ...
3
votes
1answer
141 views

Does parallel mergesort run differently on mesh vs linear array of processors?

I'm currently taking course on introduction to algorithm and I came across the parallel mergesort algorithm. My question is: Is there any differences in the algorithm plan if it runs on a 2d mesh ...
0
votes
2answers
286 views

Diagram to express parallelism in a process workflow

I'm modelling part of a software architecture on which several processes run as a workflow. The architecture involves data parallelism, where a certain serial process produces N pieces of data which ...
18
votes
1answer
686 views

Using uniqueness types to implement safe parallelism

I've been interested in uniqueness types as an alternative to monads in pure functional languages for some time; unfortunately, this is kind of an esoteric area of CS research and online resources ...
0
votes
0answers
140 views

Whats the best way to parallel my problem using Java API

I´m with trouble, because I want to make faster my code using threads, fork in join or any kind of parallel. I did a code using fork in join but I saw my arraylist isn´t getting the correct values. ...
0
votes
4answers
149 views

Data Structure for Small Number of Agents in a Relatively Big 2D World

I'm working on a project where we will implement a kind of world simulation where there is a square 2D world. Agents live on this world and make decisions like moving or replicating themselves based ...
2
votes
1answer
511 views

Python multithreading and utilizing modern processors - what is the downside?

CPython implementation detail: In CPython, due to the Global Interpreter Lock, only one thread can execute Python code at once (even though certain performance-oriented libraries might overcome ...
2
votes
6answers
386 views

Is an atomic action supposed to be deterministic?

I was reading about the at most once property that defines what an atomic action is and I've been curios about this example: x = 0, y = 0 x = y + 1 || y = y + 1 If we use the 'at most once' ...
6
votes
1answer
616 views

Which parallel pattern to use?

I need to write a server application that fetches mails from different mail servers/mailboxes and then needs to process/analyze these mails. Traditionally, I would do this multi-threaded, launching a ...
13
votes
1answer
2k views

Best practise is not to poll…but isn't polling happening internally anyway when a thread calls wait()?

Say we have some thread that wants to check when another thread is finished its task. I have read that we should call a wait() type function that will make this thread wait until it receives a ...
18
votes
5answers
26k views

The difference between “concurrent” and “parallel” execution?

What is the difference between the terms concurrent and parallel execution? I've never quite been able to grasp the distinction. The tag defines concurrency as a manner of running two processes ...
2
votes
3answers
198 views

Is there a way to calculate whether to spawn a new thread or use current thread

I am building an interpret DSL in which parallelism is part of the language - the user simply states that a calculation can be done in parallel and the interpreter may decide whether to make the ...
10
votes
4answers
1k views

What is Java's primary focus? Why does it take so long to get new features?

I have been exploring the new features in the JDK8, like the lambda expressions, the extension methods, and the new stream API. Evidently none of these features are new in the programming world and ...
3
votes
1answer
129 views

Parallelization: Choice of communication model

Disclaimer: If you're not into parallelization (on clusters), this question is probably not interesting to you and probably not worth a read. TL;DR: I search for a communication model (preferably ...
1
vote
1answer
959 views

Parallel computing using xcode

I'm making mandelbrot fractals in C using Xcode and I want to use parallel computing but everything I've tried so far doesn't work. Such as This Question and other how to guides. Whats the easiest way ...
9
votes
3answers
2k views

Parallelism implies concurrency but not the other way round right?

I often read that parallelism and concurrency are different things. Very often the answerers/commenters go as far as writing that they're two entirely different things. Yet in my view they're related ...
4
votes
8answers
723 views

When should I use parallelism? [closed]

After asking this question, I got to realize that parallelism may not always be good. So far I can see that parallelism (under c#) is A little complicated code-wise Will probably insert some ...
9
votes
1answer
200 views

Prolog parallelism

Are there any prolog interpreters that can functionally decompose your 'programs' in order to improve efficiency? I know there's been research on prolog interpreters that reach near-C speeds through ...
3
votes
2answers
276 views

Optimum Number of Parallel Processes

I just finished coding a (basic) ray tracer in C# for fun and for the learning experience. Now I want to further that learning experience. It seems to me that ray tracing is a prime candidate for ...
8
votes
2answers
637 views

Anyone know of any parallelizing compilers following the approach of the Dragon Book? [closed]

In Compilers: Principles, Techniques, & Tools, Aho et al describe an approach for optimizing for parallelism (chapter 11 in the second edition). Is anyone aware of any existing compilers which ...
2
votes
5answers
260 views

Where could SPMD parallel programming be used in a Compiler?

I have little knowledge about the subjects of compiler construction and parallel programming, so please bear with me. This is a course about compiler construction, and we are asked to learn CUDA while ...
7
votes
5answers
253 views

When developing a piece of software, when do you start thinking/designing the concurrent sections?

Following along with the principle of not optimizing too early, I'm wondering at what point in the design / development of a piece of software do you start thinking about the concurrency ...
5
votes
2answers
1k views

Is there a standard pseudocode for parallel algorithms?

The common styles of pseudocode are largely intelligible, and it is more or less clear how to write pseudocode for sequential programs. But if parallelism is not hidden behind a full library and is ...
3
votes
2answers
285 views

What pitfalls and gotchas commonly occur when beginning with Parallel and Concurrent Programming with C? [closed]

It roughly three weeks I will be taking a Parallel programming class that is taught using C for the assignments. I have a fairly strong interest in the subject at present and my C skills aren't ...
5
votes
6answers
433 views

What is the *correct* term for a program that makes use of multiple hardware processor cores?

I want to say that my program is capable of splitting some work across multiple CPU cores on a single system. What is the simple term for this? It's not multi-threaded, because that doesn't ...
3
votes
3answers
294 views

How to you solve the problem of implicit locking and parallel execution?

Where the code is: function A() { lock() doSomething() unlock() } We can call A safely from multiple threads, but it never be executed in parallel . For parallel execution, we have to ...
3
votes
2answers
1k views

Graphic card for parallel programming vs traditional methods

With a simple search in amazon one can see that the modern approach for parallel programming is to use your graphic card. However I am still a little bit skeptical about it. My last computer has an 8 ...
73
votes
10answers
9k views

How to explain why multi-threading is difficult

I am a fairly good programmer, my boss is also a fairly good programmer. Though he seems to underestimate some tasks such as multi-threading and how difficult it can be (I find it very difficult for ...
11
votes
5answers
784 views

Why is implicit parallelism/concurrency not more widespread? [closed]

Implicit parallelism^ can take a big burden away from many programmers, placing it on the computer. So... why is it is not more widespread at present? ^ Implicit parallelism is to make a computer be ...
20
votes
5answers
6k views

Is objected oriented programming paradigm outdated since it is anti-modular and anti-parallel? [closed]

I have read the controversial article Teaching FP to freshmen posted by Robert Harper who is a professor in CMU. He claimed that CMU would no longer teach object oriented programming in the ...
1
vote
5answers
1k views

Examples of concurrent iterating scenarios needed

I'm trying to wrap my head around different concurrency solutions to several threads iterating over the same collection but I'm having difficulty coming up with good realistic (but preferably easy to ...
0
votes
1answer
411 views

Parallel programming against a database: managing locks and transactions

I have first experience of parallel programming of code which actively works with relational database. I find it interesting to combine .NET parallel programming primitives with database ...
6
votes
4answers
1k views

how to deal with parallel programming [closed]

I know that parallel programming is a big resource in computer graphics, with moder machines, and mayebe a computing model that will be grow up in the near future (is this trend true?). I want to ...
26
votes
10answers
3k views

Concurrency: How do you approach the design and debug the implementation?

I've been developing concurrent systems for several years now, and I have a pretty good grasp on the subject despite my lack of formal training (i.e. no degree). There's a few new languages that have ...
5
votes
4answers
2k views

What is a “task pool”?

I have searched for many websites for a definition of "task pool", but most descriptions are very vague. Anywhere I can find a precise definition of it? More details. Are dependencies allowed in ...
10
votes
2answers
244 views

What would be the best way to handle errors in parallel programs?

With parallel algorithms knocking at the door, it might be a good time to think about error handling. So at first there were error codes. Those sucked. It was free to ignore them, so you could fail ...