Search Results

Search found 1965 results on 79 pages for 'quantum computing'.

Page 62/79 | < Previous Page | 58 59 60 61 62 63 64 65 66 67 68 69  | Next Page >

• Efficiency of while(true) ServerSocket Listen

  - by Submerged

  I am wondering if a typical while(true) ServerSocket listen loop takes an entire core to wait and accept a client connection (Even when implementing runnable and using Thread .start()) I am implementing a type of distributed computing cluster and each computer needs every core it has for computation. A Master node needs to communicate with these computers (invoking static methods that modify the algorithm's functioning). The reason I need to use sockets is due to the cross platform / cross language capabilities. In some cases, PHP will be invoking these java static methods. I used a java profiler (YourKit) and I can see my running ServerSocket listen thread and it never sleeps and it's always running. Is there a better approach to do what I want? Or, will the performance hit be negligible? Please, feel free to offer any suggestion if you can think of a better way (I've tried RMI, but it isn't supported cross-language. Thanks everyone

  Read the article

• What's the coolest machine you've ever worked on?

  - by mxg

  What's the most exotic, coolest, unique, or interesting machine you've worked on? Most of us work on machines with x86 architectures using some Windows or Linux variant. I'm sure there are those of you out there who are working on or have worked on machines with experimental architecures, or operating systems. Maybe you worked on a machine that has some sigificance in the history of computing. I'd be interested to hear about it. I'm sure others reading SO will as well. EDIT: I appreciate all of you who took some time to talk about their experiences with interesting or unusual machines. I enjoyed reading your answers. Although it wasn't my intent to get nostalgic, I see that theme amongst the responses.

  Read the article

• Semantic stuff (RDF, OWL) on mobile phones - is it possible?

  - by Brian Schimmel

  I'm thinking about using semantic (web) technogies like RDF and OWL in an application on mobile devices. Currently I'm targeting android, but I'd also be interested in the possibilities on the iPhone and on J2ME. I would like to use a lib instead of implementing everything from scratch. I know that there are some libraries and frameworks like Jena, Redland, Protégé but they don't state on which platforms they are known to work. Having a dynamic object model and parsing from and to XML are must-haves for me. I'd also like to use reasoning, but I've been told it was rather computing-intensive, so that's only a nice-to-have. For all platforms mentioned, the question can be interpreted as Is it possible in theory (especially for J2ME I'm not sure) Are there libs that are known to work on those platforms? Is the performance on a mobile platform good enough for real world usage?

  Read the article

• How to leverage Spring Integration in a real-world JMS distributed architecture?

  - by ngeek

  For the following scenario I am looking for your advices and tips on best practices: In a distributed (mainly Java-based) system with: many (different) client applications (web-app, command-line tools, REST API) a central JMS message broker (currently in favor of using ActiveMQ) multiple stand-alone processing nodes (running on multiple remote machines, computing expensive operations of different types as specified by the JMS message payload) How would one best apply the JMS support provided by the Spring Integration framework to decouple the clients from the worker nodes? When reading through the reference documentation and some very first experiments it looks like the configuration of an JMS inbound adapter inherently require to use a subscriber, which in a decoupled scenario does not exist. Small side note: communication should happen via JMS text messages (using a JSON data structure for future extensibility).

  Read the article

• Can SHA-1 algorithm be computed on a stream? With low memory footprint?

  - by raoulsson

  I am looking for a way to compute SHA-1 checksums of very large files without having to fully load them into memory at once. I don't know the details of the SHA-1 implementation and therefore would like to know if it is even possible to do that. If you know the SAX XML parser, then what I look for would be something similar: Computing the SHA-1 checksum by only always loading a small part into memory at a time. All the examples I found, at least in Java, always depend on fully loading the file/byte array/string into memory. If you even know implementations (any language), then please let me know!

  Read the article

• Mahout Recommendations on Binary data

  - by Pranay Kumar

  Hi, I'm a newbie to mahout.My aim is to produce recommendations on binary user purchased data.So i applied item-item similarity model in computing top N recommendations for movie lens data assuming 1-3 ratings as a 0 and 4-5 ratings as a 1.Then i tried evaluating my recommendations with the ratings in the test-data but hardly there have been two or three matches from my top 20 recommendations to the top rated items in test data and no match for most users. So are my recommendations totally bad by nature or do i need to go for a different measure for evaluating my recommendations ? Please help me ! Thanks in advance. Pranay, 2nd yr ,UG student.

  Read the article

• Storing dates as UTC in database

  - by James

  I am storing date/times in the database as UTC and computing them inside my application back to local time based on the specific timezone. Say for example I have the following date/time: 01/01/2010 00:00 Say it is for a country e.g. UK which observes DST (Daylight Savings Time) and at this particular time we are in daylight savings. When I convert this date to UTC and store it in the database it is actually stored as: 31/12/2009 23:00 As the date would be adjusted -1 hours for DST. This works fine when your observing DST. However, what happens when the clock is adjusted back? When I pull that date from the database and convert it to local time that particular datetime would be seen as 31/12/2009 23:00 when in reality it was processed as 01/01/2010 00:00. Correct me if I am wrong but isn't this a bit of a flaw when storing times as UTC?

  Read the article

• starting 64 Bit Windows Application Development

  - by user173438

  I intend to start writing a 64 Bit Scientific Computing Application (signal processing) for Windows using Microsoft Visual Studio 2008. What should I have ready as far as a development platform is concerned? How would it be different from 32 Bit development? What could be the porting issues for a 32 Bit version that I already have (ok - this might too early to ask.. even before I start compiling)? As you might have guessed, I am looking for general directions. All pointers would be much appreciated! :) Thanks in advance..

  Read the article

• Orbital equations, and power required to run them

  - by Adam Davis

  Due to a discussion on the SO IRC today, I'm curious about orbital mechanics, and The equations needed to solve orbital problems The computing power required to solve complex problems The question in particular is calculating when the Earth will plow into the Sun (or vice versa, depending on the frame of reference). I suspect that all the gravitational pulls within our solar system may need to be calculated, which makes me wonder what type of computer cluster is required, or can this be done on a single box? I don't have the experience to do a back of the napkin test here, but perhaps you do? Also, much thx to Gortok for the original inspiration (see comments).

  Read the article

• Adobe Flex + Air or Java + JavaFX 2.0?

  - by kuyapangu

  Hey guys! I'm looking into a cloud-computing related career. I've recently graduated from school and have been meaning to study a new programming language. From what I understand, I need to get into RIA development for this. Flex and Java have certainly caught my attention, but I am torn as to whether focus on Flex then continue with Air, or study Java first and see how JavaFX 2.0 pans out, and then continue with Flex thereafter. I've no previous experience with either, and I'm sort of giving myself something like two years or so to learn. What do guys think? Thanks for the feedback! :)

  Read the article

• How can I use Amazon's API in PHP to search for books?

  - by TerranRich

  I'm working on a Facebook app for book sharing, reviewing, and recommendations. I've scoured the web, searched Google using every search phrase I could think of, but I could not find any tutorials on how to access the Amazon.com API for book information. I signed up for an AWS account, but even the tutorials on their website didn't help me one bit. They're all geared toward using cloud computing for file storage and processing, but that's not what I want. I just want to access their API to search info on books. Kind of like how http://openlibrary.org/ does it, where it's a simple URL call to get information on a book (but their databases aren't nearly as populated as Amazon's). Why is it so damned hard to find the information I need on Amazon's AWS site? If anybody could help, I would greatly appreciate it.

  Read the article

• Why might different computers calculate different arithmetic results in VB.NET?

  - by Eyal

  I have some software written in VB.NET that performs a lot of calculations, mostly extracting jpegs to bitmaps and computing calculations on the pixels like convolutions and matrix multiplication. Different computers are giving me different results despite having identical inputs. What might be the reason? Edit: I can't provide the algorithm because it's proprietary but I can provide all the relevant operations: ULong \ ULong (Turuncating division) Bitmap.Load("filename.bmp') (Load a bitmap into memory) Bitmap.GetPixel(Integer, Integer) (Get a pixel's brightness) Double + Double Double * Double Math.Sqrt(Double) Math.PI Math.Cos(Double) ULong - ULong ULong * ULong ULong << ULong List.OrderBy(Of Double)(Func) Hmm... Is it possible that OrderBy is using a non-stable QuickSort and that QuickSort is using a random pivot? Edit: Just tested, nope. The sort is stable.

  Read the article

• A simple algorithm for polygon intersection

  - by Elazar Leibovich

  I'm looking for a very simple algorithm for computing the polygon intersection/clipping. That is, given polygons P, Q, I wish to find polygon T which is contained in P and in Q, and I wish T to be maximal among all possible polygons. I don't mind the run time (I have a few very small polygons), I can also afford getting an approximation of the polygons' intersection (that is, a polygon with less points, but which is still contained in the polygons' intersection). But it is really important for me that the algorithm will be simple (cheaper testing) and preferably short (less code). edit: please note, I wish to obtain a polygon which represent the intersection. I don't need only a boolean answer to the question of whether the two polygons intersect.

  Read the article

• Algorithm to distribute objects in a box (like InDesign, Illustrator, Draw!)

  - by Rafael Almeida

  I have a set of rectangles with their corresponding positions and a big rectangle which serves as the 'bounding box' for these rectangles. I would like to know of an algorithm that would 'distribute the free space' evenly among the rectangles. Some of you may be familiar with the Distribute Spacing option in Adobe InDesign and similar layout-oriented apps. That would be what I'm looking for. I did try looking it up, but I'm not familiar with 'graphical' algorithms terminology and trying only terms relating to 'distribute' mainly yields results about Distributed Computing. So, even the names of the algorithms or better terms to look up would be a big help. Finally, the algorithm doesn't need to be rigorously the same as InDesign's one: pretty much any algorithm that 'distributes' objects inside a region will work fine. In fact, since I'm striving for visual appeal mainly, the more suggestions the better. =D

  Read the article

• Efficiently compute the row sums of a 3d array in R

  - by Gavin Simpson

  Consider the array a: > a <- array(c(1:9, 1:9), c(3,3,2)) > a , , 1 [,1] [,2] [,3] [1,] 1 4 7 [2,] 2 5 8 [3,] 3 6 9 , , 2 [,1] [,2] [,3] [1,] 1 4 7 [2,] 2 5 8 [3,] 3 6 9 How do we efficiently compute the row sums of the matrices indexed by the third dimension, such that the result is: [,1] [,2] [1,] 12 12 [2,] 15 15 [3,] 18 18 ?? The column sums are easy via the 'dims' argument of colSums(): > colSums(a, dims = 1) but I cannot find a way to use rowSums() on the array to achieve the desired result, as it has a different interpretation of 'dims' to that of colSums(). It is simple to compute the desired row sums using: > apply(a, 3, rowSums) [,1] [,2] [1,] 12 12 [2,] 15 15 [3,] 18 18 but that is just hiding the loop. Are there other efficient, truly vectorised, ways of computing the required row sums?

  Read the article

• What to see in India as a developer and student

  - by lasseespeholt

  Hi, I'm planning a trip to India around July-August. And I want to hear Indian developers or developers traveled to India if there are something interesting to see in India (around Bombay) for developers in general. Maybe a conference etc. I have looked at http://www.conferencealerts.com/computing.htm I have studied computer science in a year now but have been a spare time and independent developer for some years now. Furthermore, I have tried finding summer courses but that is properly too late now and computer science summer courses is hard to find in India. Best regards, Lasse Espeholt

  Read the article

• Support-function in the GJK-algorithm.

  - by Marcus Johansson

  I am trying to implement the GJK-algorithm but I got stuck instantly. The problem is to implement the Support-function that isn't O(n^2). As it is now I'm computing the complete Minkowski difference, and then there is really no point in doing the GJK-algorithm. (or is it?) What I mean by Support-function is the function that returns the point in the Minkowski difference that is furthest away in a specified direction. I assume this shouldn't be O(n^2) as it is in my current implementation.

  Read the article

• No method 'get' on backbone model save

  - by user888734

  I'm using backbone for a reasonably complicated form. I have a number of nested models, and have been computing other variables in the parent model like so: // INSIDE PARENT MODEL computedValue: function () { var value = this.get('childModel').get('childModelProperty'); return value; } This seems to work fine for keeping my UI in sync, but as soon as I call .save() on the parent model, I get: Uncaught TypeError: Object #<Object> has no method 'get' It seems that the child model kind of temporarily stops responding. Am I doing something inherently wrong? EDIT: The stack trace is: Uncaught TypeError: Object #<Object> has no method 'get' publish.js:90 Backbone.Model.extend.neutralDivisionComputer publish.js:90 Backbone.Model.extend.setNeutralComputed publish.js:39 Backbone.Events.trigger backbone.js:163 _.extend.change backbone.js:473 _.extend.set backbone.js:314 _.extend.save.options.success backbone.js:385 f.Callbacks.o jquery.min.js:2 f.Callbacks.p.fireWith jquery.min.js:2 w jquery.min.js:4 f.support.ajax.f.ajaxTransport.send.d

  Read the article

• gcc options for fastest code

  - by rwallace

  I'm distributing a C++ program with a makefile for the Unix version, and I'm wondering what compiler options I should use to get the fastest possible code (it falls into the category of programs that can use all the computing power they can get and still come back for more), given that I don't know in advance what hardware, operating system or gcc version the user will have, and I want above all else to make sure it at least works correctly on every major Unix-like operating system. Thus far, I have g++ -O3 -Wno-write-strings, are there any other options I should add? On Windows, the Microsoft compiler has options for things like fast calling convention and link time code generation that are worth using, are there any equivalents on gcc? (I'm assuming it will default to 64-bit on a 64-bit platform, please correct me if that's not the case.)

  Read the article

• How to save the world from your computer?

  - by Francisco Garcia

  Sometimes I miss the "help other people" factor within computer related careers. Sure that out there I could find many great projects improving society, but that is not common. However there are little things that we all can do to make this a better place beyond trying to erradicate annoynig stuff such as Visual Basic. You could join a cloud computing network such as World Community Grid to fight cancer. Write a charityware application such as Vim, improve an office IT infrastructure to support telecommuting and reduce CO2 emissions, use an ebook reader for saving paper... what else would you? which projects do you think can have an impact?

  Read the article

• Count of memory copies in *nix systems between packet at NIC and user application?

  - by Michael_73

  Hi there, This is just a general question relating to some high-performance computing I've been wondering about. A certain low-latency messaging vendor speaks in its supporting documentation about using raw sockets to transfer the data directly from the network device to the user application and in so doing it speaks about reducing the messaging latency even further than it does anyway (in other admittedly carefully thought-out design decisions). My question is therefore to those that grok the networking stacks on Unix or Unix-like systems. How much difference are they likely to be able to realise using this method? Feel free to answer in terms of memory copies, numbers of whales rescued or areas the size of Wales ;) Their messaging is UDP-based, as I understand it, so there's no problem with establishing TCP connections etc. Any other points of interest on this topic would be gratefully thought about! Best wishes, Mike

  Read the article

• Whats the deal with python?

  - by gmatt

  My interests in programming lie mainly in algorithms, and lately I have seen many reputable researchers write a lot of their code in python. How easy and convenient is python for scientific computing? Does it have a library of algorithms that compares to matlab's? Is Python a scripting language or does it compile? Is it a great language for prototyping an algorithm? How long would it take me to learn enough of it to be productive provided I know C well and OO programming somewhat? Is it OO based? Sorry for the condensed format of questions, but I'm very curious and was hoping a more experienced programmer could help me out.

  Read the article

• How to use your computer to save the world?

  - by Francisco Garcia

  Sometimes I miss the "help other people" factor within computer-related fields. However, there are little things that we all can do to make this a better place—beyond trying to eradicate annoying stuff such as Visual Basic. You could join a cloud computing network such as World Community Grid to fight cancer, write a charityware application such as Vim, improve office IT infrastructure to support telecommuting and reduce CO2 emissions, use an ebook reader to save paper, ... What else can we do to help others? Which projects can have the biggest impact?

  Read the article

• SRAM Cell Diagram - Can someone explain this a bit more clearly? ( From COMP1917 @ UNSW: Lecture 2 o

  - by Kristina

  I've begun watching a series of first year lectures from the University of New South Wales (UNSW) in Australia, and I'm a bit perplexed by the instructors explanation of how an SRAM gate works. I realize this isn't exactly "programming-related" but since it comes from a series of lectures relating to computing and programming, I thought StackOverflow may be able to help (reddit failed me entirely). In this lecture beginning at around 32:12, Richard (the lecturer) tries to explain how a "latch gate" works within SRAM. Although his students seem to keep up, I feel I'm missing something crucial which is preventing the concept from really "clicking" in my brain. For convenience, I've added the image from the video below: Thanks in advance for any help you can provide, but if this question doesn't fit your view of "programming-related" could you please provide an alternate forum for this in a comment when you cast your close vote? Thanks!

  Read the article

• why don't more programming languages have builtin interfaces to the window manager?

  - by Naveen

  Programming is at the heart about automating tasks on a computer. Presumably those tasks would normally be done manually by a human. Humans use the computer through the keyboard, mouse, and interaction with the console or the window manager. But very few languages have built in functions that provide an interface to these basic computing objects. A notable exception is autohotkey, an open source language on windows, providing builtin functions that allow the following simple tasks: * Get Pixel Information * Get mouse position * Keyboard macros * Simulate key strokes * Simulate mouse click * Window management See examples on rosettacode. There have been various attempts on linux, many of which were stopped without explanation. One is the inactive tcl library: android. Search google code for android, lang:tcl

  Read the article

< Previous Page | 58 59 60 61 62 63 64 65 66 67 68 69  | Next Page >