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  • how to elegantly duplicate a graph (neural network)

    - by macias
    I have a graph (network) which consists of layers, which contains nodes (neurons). I would like to write a procedure to duplicate entire graph in most elegant way possible -- i.e. with minimal or no overhead added to the structure of the node or layer. Or yet in other words -- the procedure could be complex, but the complexity should not "leak" to structures. They should be no complex just because they are copyable. I wrote the code in C#, so far it looks like this: neuron has additional field -- copy_of which is pointer the the neuron which base copied from, this is my additional overhead neuron has parameterless method Clone() neuron has method Reconnect() -- which exchanges connection from "source" neuron (parameter) to "target" neuron (parameter) layer has parameterless method Clone() -- it simply call Clone() for all neurons network has parameterless method Clone() -- it calls Clone() for every layer and then it iterates over all neurons and creates mappings neuron=copy_of and then calls Reconnect to exchange all the "wiring" I hope my approach is clear. The question is -- is there more elegant method, I particularly don't like keeping extra pointer in neuron class just in case of being copied! I would like to gather the data in one point (network's Clone) and then dispose it completely (Clone method cannot have an argument though).

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  • How can I refactor this to work without breaking the pattern horribly?

    - by SnOrfus
    I've got a base class object that is used for filtering. It's a template method object that looks something like this. public class Filter { public void Process(User u, GeoRegion r, int countNeeded) { List<account> selected = this.Select(u, r, countNeeded); // 1 List<account> filtered = this.Filter(selected, u, r, countNeeded); // 2 if (filtered.Count > 0) { /* do businessy stuff */ } // 3 if (filtered.Count < countNeeded) this.SendToSuccessor(u, r, countNeeded - filtered) // 4 } } Select(...), Filter(...) are protected abstract methods and implemented by the derived classes. Select(...) finds objects in the based on x criteria, Filter(...) filters those selected further. If the remaining filtered collection has more than 1 object in it, we do some business stuff with it (unimportant to the problem here). SendToSuccessor(...) is called if there weren't enough objects found after filtering (it's a composite where the next class in succession will also be derived from Filter but have different filtering criteria) All has been ok, but now I'm building another set of filters, which I was going to subclass from this. The filters I'm building however would require different params and I don't want to just implement those methods and not use the params or just add to the param list the ones I need and have them not used in the existing filters. They still perform the same logical process though. I also don't want to complicated the consumer code for this (which looks like this) Filter f = new Filter1(); Filter f2 = new Filter2(); Filter f3 = new Filter3(); f.Sucessor = f2; f2.Sucessor = f3; /* and so on adding filters as successors to previous ones */ foreach (User u in users) { foreach (GeoRegion r in regions) { f.Process(u, r, ##); } } How should I go about it?

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  • How to maintain a pool of names ?

    - by Jacques René Mesrine
    I need to maintain a list of userids (proxy accounts) which will be dished out to multithreaded clients. Basically the clients will use the userids to perform actions; but for this question, it is not important what these actions are. When a client gets hold of a userid, it is not available to other clients until the action is completed. I'm trying to think of a concurrent data structure to maintain this pool of userids. Any ideas ? Would a ConcurrentQueue do the job ? Clients will dequeue a userid, and add back the userid when they are finished with it.

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  • Need some help understanding this problem

    - by Legend
    I was wondering if someone could help me understand this problem. I prepared a small diagram because it is much easier to explain it visually. Problem I am trying to solve: 1. Constructing the dependency graph Given the connectivity of the graph and a metric that determines how well a node depends on the other, order the dependencies. For instance, I could put in a few rules saying that node 3 depends on node 4 node 2 depends on node 3 node 3 depends on node 5 But because the final rule is not "valuable" (again based on the same metric), I will not add the rule to my system. 2. Execute the request order Once I built a dependency graph, execute the list in an order that maximizes the final connectivity. First and foremost, I am wondering if I constructed the problem correctly and if I should be aware of any corner cases. Secondly, is there a closely related algorithm that I can look at? Currently, I am thinking of something like Feedback Arc Set or the Secretary Problem but I am a little confused at the moment. Any suggestions? PS: I am a little confused about the problem myself so please don't flame on me for that. If any clarifications are needed, I will try to update the question.

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  • HTML-like GUI Framework in Java

    - by wintermute
    I was recently brought onto a project where we are developing a lot GUI elements for BlackBerry devices. The standard RIM APIs are pretty basic, almost never do what is required and are difficult or impossible to extend, so we end up re-implementing chunks of it. Currently the code we have isn't super organized and factored so there are lots of little tricks that get implemented over and over again. I had a thought about how to aid development efforts on this platform and wanted to see if the community could tell me if I'm still sane or if I've gone totally nuts. By far, the biggest organizational problem I've run into is making sure that each screen is laid out properly with proper padding and such. The current approach is to manually keep track of padding like so: protected void sublayout(int width, int height) { final int padding = 5; int y = padding; int x = padding; layoutChild(_someChild, width - padding * 2, height / 3 - padding * 2); setPositionChild(_someChild, x, y); y += _someChild.getHeight() + padding; // Calculate where to start drawing next. /* ... snipped ... */ } As you can see, positioning elements on a screen is a nightmare due to the tedium. I have investigated other GUI frameworks but, for a variety of reasons, it is difficult to find one that suites our purposes. One potential solution that came to me is to create a GUI framework who's API resembles HTML/CSS. This would allow for things like padding, margins, borders and colours to be handled through a sort of CSS API while the content would be organized using the HTML part of the API. It might look something like this: public class OptionsScreen extends Document { public OptionsScreen() { // You would set the style (like CSS style) through the constructor. Div content = new Div(new Style(new Padding(5), Color.BLACK)); // Then build up a tree of elements which can each have their own style's. // Each element knows how to draw itself, but it doesn't have to worry about // manually handling things like padding. // content.addChild(new P("This is a paragraph", new Style(new Padding(), Color.RED))); Ul list = new Ul(); list.addChild(new Li("item 1")); list.addChild(new Li("item 2")); content.addChild(list); addChild(content); } } I can imagine this making it easier to customize the UI of our app (which is very important) with different fonts, colours and layouts. Does this idea belong on The Daily WTF or do you think there is some promise?

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  • Is it a good idea to work on header files only, just at the start of the project?

    - by m4design
    To explain my point further, I'm a beginner in programming, and I'm working on a small project. Instead of separating the .cpp file from the header file, I'm implementing the code in the header files, and making one .cpp file for testing. I do this to have less files, hence easier navigation. Then later I'll separate the code as it should be. Will this cause any problems? should I continue doing that? Thanks.

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  • Does C# allow method overloading, PHP style (__call)?

    - by mr.b
    In PHP, there is a special method named __call($calledMethodName, $arguments), which allows class to catch calls to non-existing methods, and do something about it. Since most of classic languages are strongly typed, compiler won't allow calling a method that does not exist, I'm clear with that part. What I want to accomplish (and I figured this is how I would do it in PHP, but C# is something else) is to proxy calls to a class methods and log each of these calls. Right now, I have code similar to this: class ProxyClass { static logger; public AnotherClass inner { get; private set; } public ProxyClass() { inner = new AnotherClass(); } } class AnotherClass { public void A() {} public void B() {} public void C() {} // ... } // meanwhile, in happyCodeLandia... ProxyClass pc = new ProxyClass(); pc.inner.A(); pc.inner.B(); // ... So, how can I proxy calls to an object instance in extensible way? Extensible, meaning that I don't have to modify ProxyClass whenever AnotherClass changes. In my case, AnotherClass can have any number of methods, so it wouldn't be appropriate to overload or wrap all methods to add logging. I am aware that this might not be the best approach for this kind of problem, so if anyone has idea what approach to use, shoot. Thanks!

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  • ASCII Diagram Tool

    - by Jon
    I'm looking for an ASCII diagram tool for producing diagrams from text. I only really need sequence and state type diagrams for now, but I'm curious as to what people would recommend? I need something which is standalone, not a web based tool that works on Linux, OSX and Windows.

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  • Why does C++ mandate that complex only be instantiated for float, double, or long double?

    - by templatetypedef
    According to the C++ ISO spec, §26.2/2: The effect of instantiating the template complex for any type other than float, double or long double is unspecified. Why would the standard authors explicitly add this restriction? This makes it unspecified, for example, what happens if you make complex<int> or a complex<MyCustomFixedPointType> and seems like an artificial restriction. Is there a reason for this limitation? Is there a workaround if you want to instantiate complex with your own custom type? I'm primarily asking this question because of this earlier question, in which the OP was confused as to why abs was giving bizarre outputs for complex<int>. That said, this still doesn't quite make sense given that we also might want to make complex numbers out of fixed-points types, higher-precision real numbers, etc. Thanks!

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  • Building a wiki like data model in rails question.

    - by lillq
    I have a data model in which I would like to have an item that has a description that can be edited. I would like to also keep track of all edits to the item. I am running into issues with my current strategy, which is: class Item < ActiveRecord::Base has_one :current_edit, :class_name => "Edit", :foreign_key => "current_edit_id" has_many :edits end class Edit < ActiveRecord::Base belongs_to :item end Can the Item have multiple associations to the same class like this? I was thinking that I should switch to keeping track of the edit version in the Edit object and then just sorting the has_many relationship base on this version.

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  • What's the proper way of importing option lists into an Android app?

    - by Scott
    I have been storing option lists for my Android app in a cloud table. For example, categories like "historical fiction","biography","science fiction", etc. I see the following pros and cons: Pro: I can make changes to the list without sending an app update to Google Play Not normalized - I can use the text in my other data tables instead of a reference ID Con: App needs to take time to download from the web each time (or at least check for changes) English only I believe the "proper" way to do this is the use the XML resource files. But I need to make sure the selection references correctly with my data. That is, my app needs to understand that "Poetry" and "Poesía" are the same thing. Is the correct thing to do: Forget about it since I'll never get to the point where I'm translating my app anyway Use a string-array and use the index (0...x) to know what the selection is Use a 2-dimensional string-array with a reference ID in the first column and the text in the second?

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  • Where are the new ideas in programming languages?

    - by 0xF
    I've recently been looking into the topic of programming languages and from what I've seen, few to none serious languages try making really "new" things that were not seen before their creation. Why do all more or less successful programming languages since 1980 or so just combine aspects of their predecessors? I just can't believe that programming languages "can't get any better"..

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  • How to change source order of <div> in less steps/automatically?

    - by metal-gear-solid
    How can i do this task automate. i need to change source order of div, which has same id in above 100 pages. i created example This is default condition <div class="identification"> <div class="number">Number 1</div> </div> <div class="identification"> <div class="number">Number 2</div> </div> <div class="identification"> <div class="number">Number 3</div> </div> <div class="identification"> <div class="number">Number 4</div> </div> <div class="identification"> <div class="number">Number 5</div> </div> <div class="identification"> <div class="number">Number 6</div> </div> I need lik this <div class="identification"> <div class="number">Number 1</div> </div> <div class="identification"> <div class="number">Number 3</div> </div> <div class="identification"> <div class="number">Number 2</div> </div> <div class="identification"> <div class="number">Number 6</div> </div> <div class="identification"> <div class="number">Number 4</div> </div> <div class="identification"> <div class="number">Number 5</div> </div> Is the manual editing only option? I use dreamweaver.

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  • Self-Configuring Classes W/ Command Line Args: Pattern or Anti-Pattern?

    - by dsimcha
    I've got a program where a lot of classes have really complicated configuration requirements. I've adopted the pattern of decentralizing the configuration and allowing each class to take and parse the command line/configuration file arguments in its c'tor and do whatever it needs with them. (These are very coarse-grained classes that are only instantiated a few times, so there is absolutely no performance issue here.) This avoids having to do shotgun surgery to plumb new options I add through all the levels they need to be passed through. It also avoids having to specify each configuration option in multiple places (where it's parsed and where it's used). What are some advantages/disadvantages of this style of programming? It seems to reduce separation of concerns in that every class is now doing configuration stuff, and to make programs less self-documenting because what parameters a class takes becomes less explicit. OTOH, it seems to increase encapsulation in that it makes each class more self-contained because no other part of the program needs to know exactly what configuration parameters a class might need.

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  • C++ visitor pattern handling templated string types?

    - by Steve the Plant
    I'm trying to use the visitor pattern to serialize the contents of objects. However one snag I'm hitting is when I'm visiting strings. My strings are of a templated type, similar to STL's basic_string. So something like: basic_string<char_type, memory_allocator, other_possible_stuff> \\ many variations possible! Since I can have very many different templated string types, I can't go and add them to my visitor interface. It would be ridiculous. But I can't add templates to my VisitString method because C++ prevents using templates parameters in virtual methods. So what are my options to work around this?

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  • Good case for a Null Object Pattern? (Provide some service with a mailservice)

    - by fireeyedboy
    For a website I'm working on, I made an Media Service object that I use in the front end, as well as in the backend (CMS). This Media Service object manipulates media in a local repository (DB); it provides the ability to upload/embed video's and upload images. In other words, website visitors are able to do this in the front end, but administrators of the site are also able to do this in the backend. I'ld like this service to mail the administrators when a visitor has uploaded/embedded a new medium in the frontend, but refrain from mailing them when they upload/embed a medium themself in the backend. So I started wondering whether this is a good case for passing a null object, that mimicks the mail funcionality, to the Media Service in the backend. I thought this might come in handy when they decide the backend needs to have implemented mail functionality as well. In simplified terms I'ld like to do something like this: Frontend: $mediaService = new MediaService( new MediaRepository(), new StandardMailService() ); Backend: $mediaService = new MediaService( new MediaRepository(), new NullMailService() ); How do you feel about this? Does this make sense? Or am I setting myself up for problems down the road?

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  • Pattern for null settings

    - by user21243
    Hi, I would like to hear your thoughts and ideas about this one. in my application i have controls that are binded to objects properties. but.. the controls always looks like that: a check box, label that explain the settings and then the edited control (for ex: text box) when unchecking the checkbox i disable the text box (using binding) when the checkbox is unchecked i want the property to contain null, and when it is checked i would like the property to contain the text box's text. Of course text box can be NumericUpDown, ComboBox, DatePicker etc.. Do you have any smart way of doing it using binding or do i have to do everything on code; I really would like to a build a control that supports that and re-use it all over Ideas? Thanks,

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  • Why does C# allow abstract class with no abstract members?

    - by fatcat1111
    The C# spec, section 10.1.1.1, states: An abstract class is permitted (but not required) to contain abstract members. This allows me to create classes like this: public abstract class A { public void Main() { // it's full of logic! } } This is really a concrete class; it's only abstract in so far as one can't instantiate it. If inheritors don't actually have to provide implementation, then why call it abstract?

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  • Doctrine: Relating a model to itself using a link table, like "This event is related to to the following other events"

    - by mattalexx
    So in English, the relationship would sound like "This event is related to to the following other events". My first instinct is to create an EventEvent model, with a first_event_id field and a second_event_id field. Then I would define the following two relationships in the Event model: $this->hasMany('Event as FirstRelatedEvents', array('local' => 'first_event_id', 'foreign' => 'second_event_id', 'refClass' => 'EventEvent')); $this->hasMany('Event as SecondRelatedEvents', array('local' => 'second_event_id', 'foreign' => 'first_event_id', 'refClass' => 'EventEvent')); But I would rather not have to use two relationships on the Event model. Is there a better way to do this?

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