What is the best algorithm for solving a band-diagonal matrix?
I'm trying to figure out the best way to solve a pentadiagonal matrix. Is there something faster than gaussian elimination? ...
language-agnostic
How to find two most distant points?
This is a question that I was asked on a job interview some time ago. And I still can't figure out sensible answer. Question is: you are given set of points (x,y). Find 2 most distant points. Distant from each other. For example, for points: (0,0), (1,1), (-8, 5) - the most distant are: (1,1) and (-8,5) because the distance between th...
Use of (non) qualified names
If I want to use the name baz defined in package foo|bar|quz, I've several choices: provide fbq as a short name for foo|bar|quz and use fbq|baz use foo|bar|quz|baz import baz from foo|bar|quz|baz and then use baz (or an alias given in the import process) import all public symbols from foo|bar|quz|baz and then use baz For the langua...
Does code in the constructor add to code in subclass constructors?
Does code in the constructor add to code in subclass constructors? Or does the subclass's constructor override the superclass? Given this example superclass constructor: class Car{ function Car(speed:int){ trace("CAR speed "+speed) } } ...and this subclass constructor: class FordCar extends Car{ function For...
Best practice for near reuse of model components?
I have a requirement to use a Fund model in my code. It will contain a fund name and fund code. In the interest of reuse I've poked around the package containing the other models used and found an existing Fund model. However the issue here is that, in addition to fund name and code, it also contains an amount. Amount isn't directly ...
Is there a naming convention for a method that should set the properties of the passed object.
Hello, I am writing a method that will set the properties of an object passed as a parameter. The method accepts one parameter of type interface and the return type of the method is the same interface. I was wondering if there is some kind of a naming convention for such methods. I was thinking of something like: FillInInterfaceTypeDat...
fast thread ordering algorithm without atomic CAS
I am looking for an approach that will let me assign ordinal numbers 0..(N-1) to N O/S threads, such that the threads are in numeric order. That is, the thread that gets will have a lower O/S thread ID than the thread with ordinal 1. In order to carry this out, the threads communicate via a shared memory space. The memory ordering m...
Generating video or images of geometrical objects from data
Hello, I'm working in a course's project to predict the velocity and position of the solar system planets (and other objects). It will be really cool if I can visualize the predicted objects data, if it's possible generating 3D images, if in video that's amazing. Do you know any library that lets me to use this data to generate an ima...
Fast rectangle to rectangle intersection
What's a fast way to test if 2 rectangles are intersecting? A search on the internet came up with this one-liner (WOOT!), but I don't understand how to write it in Javascript, it seems to be written in an ancient form of C++. struct { LONG left; LONG top; LONG right; LONG bottom; } RECT; bool IntersectRe...
Implementing arrays using a stack
My programming language has no arrays, no lists, no pointers, no eval and no variable variables. All it has: Ordinary variables like you know them from most programming languages: They all have an exact name and a value. One stack. Functions provided are: push (add element to top), pop (remove element from top, get value) and empty (ch...
Language-agnostic term for typed things that need memory
Is there an accepted general term that subsumes the concepts of variables, class instances and arrays? Basically "any typed thing that needs memory". In C++, such a thing is called an object, but I'm looking for a more language-agnostic term. § 1.8 The C++ object model 1 The constructs in a C++ program create, destroy, refer to,...
How to write a spinlock without using CAS
Following on from a discussion which got going in the comments of this question. How would one go about writing a Spinlock without CAS operations? As the other question states: The memory ordering model is such that writes will be atomic (if two concurrent threads write a memory location at the same time, the result will be one or the...
What is the Software Development Lifecycle?
Our investor wants a SDLC. I've never written one before, and I don't have enough time to go and buy a book, or spend much time learning about them. From what I've been told about them, they consist of requirements (what needs to be done), and a list is done. Is this correct? Update: I have found this article which really helps to expl...
Partitioning requests in code among several servers
I have several forum servers (what they are is irrelevant) which stores posts from users and I want to be able to partition requests among these servers. I'm currently leaning towards partitioning them by geographic location. To improve the locality of data, users will be separated into regions e.g. North America, South America and so on...
Successive success checks
Most of you have probably bumped into a situation, where multiple things must be in check and in certain order before the application can proceed, for example in a very simple case of creating a listening socket (socket, bind, listen, accept etc.). There are at least two obvious ways (don't take this 100% verbatim): if (1st_ok) { if (...
What are the factors in choosing a specific Database Management System?
Why are there so many Database management systems? I am not an DB expert and I've never thought about using another Database other than mySQL. Programming languages offer different paradigms, so it makes sense to choose a specific language for your purpose. Question What are the factors in choosing a specific Database management syste...
Link to Google Streetview using Lat/Long
I'm trying to make an app that links to Google streetview using latitude/longitude coordinates, and shows a streetview of the nearest road. This is coming from a fairly small and well covered area, so there isn't going to be any coordinates in the middle of the ocean. Is there a published API showing the get parameters you need to link ...
Commenting practices?
As a student in computer engineering I have been pressured to type up very detailed comments for everything I do. I can see this being very useful for group projects or in the work place but when you work on your own projects do you spend as much time commenting? As a personal project I am working on grows more and more complicated I s...
how to tackle this combinatorial algorithm problem
I have N people who must each take T exams. Each exam takes "some" time, e.g. 30 min (no such thing as finishing early). Exams must be performed in front of an examiner. I need to schedule each person to take each exam in front of an examiner within an overall time period but avoiding a lunch break, using the minimum number of examiners...
How To Create a Flexible Plug-In Architecture?
A repeating theme in my development work has been the use of or creation of an in-house plug-in architecture. I've seen it approached many ways - configuration files (XML, .conf, and so on), inheritance frameworks, database information, libraries, and others. In my experience: A database isn't a great place to store your configuratio...