Search Results

Search found 1995 results on 80 pages for 'retro computing'.

Page 63/80 | < Previous Page | 59 60 61 62 63 64 65 66 67 68 69 70  | Next Page >

  • Help using Horner's rule and Hash Functions in JAVA?

    - by Matt
    I am trying to use Horner's rule to convert words to integers. I understand how it works and how if the word is long, it may cause an overflow. My ultimate goal is to use the converted integer in a hash function h(x)=x mod tableSize. My book suggests, because of the overflow, you could "apply the mod operator after computing each parenthesized expression in Horner's rule." I don't exactly understand what they mean by this. Say the expression looks like this: ((14*32+15)*32+20)*32+5 Do I take the mod tableSize after each parenthesized expression and add them together? What would it look like with this hash function and this example of Horner's rule?

    Read the article

  • Binomial test in Python

    - by Morlock
    I need to do a binomial test in Python that allows calculation for 'n' numbers of the order of 10000. I have implemented a quick binomial_test function using scipy.misc.comb, however, it is pretty much limited around n = 1000, I guess because it reaches the biggest representable number while computing factorials or the combinatorial itself. Here is my function: from scipy.misc import comb def binomial_test(n, k): """Calculate binomial probability """ p = comb(n, k) * 0.5**k * 0.5**(n-k) return p How could I use a native python (or numpy, scipy...) function in order to calculate that binomial probability? If possible, I need scipy 0.7.2 compatible code. Many thanks!

    Read the article

  • Need details about applications that are running on Windows Azure

    - by veda
    I have an application which requires large amount of data storage (say some PB) and computing resources. Instead of going for clusters, I am planning to propose to use Windows Azure Cloud for this application. I have gone through white papers of Windows Azure and have collected some details about Azure. But I feel that is not substantial. I need to do some case study about applications that are running on the azure and that uses azure storage efficiently. I looked for several research paper in related to performance of the applications in Windows Azure. But as Azure was quite new, I wasn't able to find any. Now, I am looking for some white papers/details regarding application that uses azure storage to substantiate my proposal. I also need to understand the windows azure storage architecture and virtual machine architecture. Do anyone know some research papers or details or blogs or something related to these topics.

    Read the article

  • In C#, can I hide/modify accessors in subclasses?

    - by Diego
    I'm not even sure what this principle is called or how to search for it, so I sincerely apologize if it has been brought up before, but the best way to do it is with an example. class Properties { public string Name { get; set; } } class MyClass { class SubProperties: Properties { public override Name { get { return GetActualName(); } set { _value = SetActualName(value); } } } public SubProperties ClassProperties; private GetActualName() { ClassProperties.Name = "name"; } private SetActualName(string s) { ClassProperties.Name = SomeOtherFunction(s); } } The idea is to have any object that instantiates MyClass have a fully accessible property ClassProperties. To that object, it would look exactly like a Properties object, but behind the scenes, MyClass is actually computing and modifying the results of the fields. This method of declaration is obviously wrong since I can't access GetActualName() and SetActualName() from within the SubProperties definition. How would I achieve something like this?

    Read the article

  • C or Ada for engineering computations?

    - by yCalleecharan
    Hi,as an engineer I currently use C to write programs dealing with numerical methods. I like C as it's very fast. I don't want to move to C++ and I have been reading a bit about Ada which has some very good sides. I believe that much of the software in big industries have been or more correctly were written in Ada. I would like to know how C compares with Ada. Is Ada fast as C? I understand that no language is perfect but I would like to know if Ada was designed for scientific computing. Thanks a lot...

    Read the article

  • Scripting window positioning in OS X

    - by Matt Trent
    My primary computing setup is a macbook pro with a large external monitor. I'm looking for a convenient way of moving a number of the windows of open programs from the laptop screen to the external monitor when I plug it in. I've seen a few partial scripts for accomplishing this, but nothing comprehensive. Ideally I'd like to specify the laptop screen location and external monitor location for each window and be able to toggle between them. Is anyone aware of any existing utility or Applscripts that can perform this?

    Read the article

  • 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

< Previous Page | 59 60 61 62 63 64 65 66 67 68 69 70  | Next Page >