Euclidean distance vs Pearson correlation vs cosine similarity?
Their goals are all the same: to find similar vectors. Which do you use in which situation? (any practical examples?) ...
computer-science
Multidimensional Collections for a (CS) Graph Class Interface in C#?
For jollies I'm trying to implement a graph data structure as an interface, so that I can implement graph classes either as adjacency lists (lists of lists of edges) or as adjacency matrices ( a 2 dimensional array of edges) with a minimum of additional code. My question is, is there a way I can implement the IGraph interface so that ei...
Recursive Sets vs Recursive Functions
What s the difference between a recursive set and recursive function? ...
NP vs NP-Complete vs NP-Hard
What are the differences between NP vs NP-Complete vs NP-Hard ? I am aware of many resources all over the web. I d like to read your explanations, and the reason is they might be different then what s out there, or it s out there and i m not aware. ...
What is "entropy and information gain"?
I am reading this book (NLTK) and it is confusing. Entropy is defined as: Entropy is the sum of the probability of each label times the log probability of that same label How can I apply entropy and maximum entropy in terms of text mining? Can someone give me a easy, simple example (visual)? ...
Formal language expressiveness of Perl patterns
Classical regular expressions are equivalent to finite automata. Most current implementations of "regular expressions" are not strictly speaking regular expressions but are more powerful. Some people have started using the term "pattern" rather than "regular expression" to be more accurate. What is the formal language classification of...
List of fundamental data structures - what am I missing?
I've been studying my fundamental data structures a bunch recently, trying to make sure I've got them down cold. By "fundamental", I mean the real basic ones. Fancy ones like Red-Black Trees and Bloom Filters are clearly worth knowing, but they're usually either enhancements of fundamental ones (Red-Black Trees are binary search trees w...
Is Computer Science For Me?
I love software development. I live for it. I spent almost 100% of my free time writing code for my latest project, priding myself on readability, a lack of complexity, and modularization. Also, since I'm graphics programming, I can also add in usability, interface, and just things that are easy on the eyes, and the fingers. Thus, when ...
Looking for novice book on combinatorics
I am looking for books on the math & computing applications of Combinatorics. Let me know your favorite books on this topic. Thanks. ...
Consider a career in programming, would like advice on which degree to choose
Hi, as the title says I'd like advice on choosing a degree for a future career in programming. I recently attended a Mastering Physics workshop at the University of Nottingham, in which I attended several lectures. One of these lectures was dedicated to the benefits of taking a physics degree. The lecturer said that physicists were oft...
MacRuby: objective-c runtime is same as ruby runtime
I have no formal education in computer science but I have been programming in Java, Ruby, jQuery for a long time. I was checking out macruby project. I keep running into statements which are similar to "In MacRuby objective-c runtime is same as ruby runtime". I understand what MRI is. I understand what ruby 1.9 is bringing to the table...
Sorting array in ruby
A user has defined the order of columns which is in an array. order = [:col1, :col2, :col3] Since the user defined columns order the state of table has changed and the current list of columns is cols = [:col1, :col4, :col3, :col5] With the given order cols need to sorted. In this case the sorted columns could look like one of the...
What are algorithms and data structures in layman’s terms?
I currently work with PHP and Ruby on Rails as a web developer. My question is why would I need to know algorithms and data structures? Do I need to learn C, C++ or Java first? What are the practical benefits of knowing algorithms and data structures? What are algorithms and data structures in layman’s terms? (As you can tell unfortunat...
exploring mathematics of/in computer science
Hi, I have been working for two years in software industry. Some things that have puzzled me are as follows: There is lack of application of mathematics in current software industry. e.g.: When a mechanical engineer designs an electricity pole , he computes the stress on the foundation by using stress analysis techniques(read mathema...
What problems have you solved using constraint programming?
I'd like to know about specific problems you - the SO reader - have solved using constraint programming and what constraint logic language you used. Questions: What problems have you used constraint programming to solve? What constraint logic language did you use? I'm looking for first-hand experiences, so please do not answer unles...
Few questions on number representation in computer?
I started learning Assembly language from the book: Introduction to 80x86 Assembly Language and Computer Architecture This is from the Representing Data in a Computer We have looked at two schemes to represent numbers- by using binary integers (often expressed in hex) or by using ASCII codes. However, these meth...
computer science: what is the big deal about big O notation.
How would big O notation help in my day to day c# programming? Is this just an academic exercise? ...
Required Reading for each CS Class
I'd like to make (or find - if it's already been made) a list of texts that are well respected in the CS community for each CS class you can take in college. I think a lot of people are educating themselves in CS (like me, I only took a few classes in college) and it would be very helpful if such a list existed. I'm talking every subje...
NFA to DFA question
First, this is not a question asking for the algorithm to convert a NFA to DFA. It's known (and proved) that the equivalent DFA of a NFA has at most 2n states, even though most of the times it will have more or less the same number of states as the NFA. How may I predict an estimate for the number of states the NFA-equivalent DFA will ...
What is regularity?
This is more of a computer science question than a programming one, but I figure that this is the best place out of all the related sites to ask this. When I discovered Regular Expressions and looked up the term I assumed that this property of "regularity" refers to the fact that the expression's language has a definable structural pat...