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• Creating a music catalog in C# and extracting first 30 seconds as soon as the first words are sung

  - by Rad

  I already read a question: Separation of singing voice from music. I don’t need this complex audio processing. I only need some detection mechanism that would detect that there is some voice/vocal playing while the music is playing (or not playing) I need to extract first 30 seconds when a vocalist starts singing along with full band music. See question 2 below. I want to create a music catalog using ASP.NET MVC 2 and Silverlight clients and C#.NET 4.0 programming language that would be front store. On the backend I would also like to create a desktop WPF/Windows application to create the music catalog from already existing music files, most of which have metadata in them ID3v1, ID3v2.3, ID3v2.4, iTunes MP4, WMA, Vorbis Comments and APE Tags etc. I would possibly like to create a web service that would allow catalog contributors to upload a zipped album and trigger metadata extraction of music data and extraction of music segments as described below. I would be happy if I achieve no. 1 below. Let's say I have 1000ths of songs in mp3 (or other formats) grouped in subfolders using some classification (Genre, Artists, Albums, Composers or other groupings). I want to create tables in DB that would organize songs so they can be searched based on different criteria (year, length, above classification or by song title, description etc) like what iTune store allows to their customers. I want to extract metadata from various formats (I will try to get songs in mp3 format, but there may be other popular formats) and allow music Catalog manager person to add missing data from either desktop or web applications. He or other contributors can upload zipped music via an HTML or Silverlight upload or WPF. Can anybody suggest open source libraries, articles, code snippets that can do that in an automatic way using .NET and possibly SQL Server DB? My main questions are these. This is an audio processing challenge. I want to extract 2 segments of music (questions 1 and 2): 1. How to extract a music segment: 1-2 seconds before a vocal starts singing and up to 30 seconds from that point in time and 2. Much more challenging is to find repeating segments (One would usually find or recognize the names of the songs and songs are usually known by these refrains. How would I go about creating a list of songs that go great together like what Genius from iTune does? Is there any characteristics of music that can be used to match songs? The goal is for people quickly scan and recognize songs i.e. associate melody, words with a title/album so they can make intelligent decisions like buying a song, create similar mood songs. Thanks, Rad

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• "Emulating" Application.Run using Application.DoEvents

  - by Luca

  I'm getting in trouble. I'm trying to emulate the call Application.Run using Application.DoEvents... this sounds bad, and then I accept also alternative solutions to my question... I have to handle a message pump like Application.Run does, but I need to execute code before and after the message handling. Here is the main significant snippet of code. // Create barrier (multiple kernels synchronization) sKernelBarrier = new KernelBarrier(sKernels.Count); foreach (RenderKernel k in sKernels) { // Create rendering contexts (one for each kernel) k.CreateRenderContext(); // Start render kernel kernels k.mThread = new Thread(RenderKernelMain); k.mThread.Start(k); } while (sKernelBarrier.KernelCount > 0) { // Wait untill all kernel loops has finished sKernelBarrier.WaitKernelBarrier(); // Do application events Application.DoEvents(); // Execute shared context services foreach (RenderKernelContextService s in sContextServices) s.Execute(sSharedContext); // Next kernel render loop sKernelBarrier.ReleaseKernelBarrier(); } This snippet of code is execute by the Main routine. Pratically I have a list of Kernel classes, which runs in separate threads, these threads handle a Form for rendering in OpenGL. I need to synchronize all the Kernel threads using a barrier, and this work perfectly. Of course, I need to handle Form messages in the main thread (Main routine), for every Form created, and indeed I call Application.DoEvents() to do the job. Now I have to modify the snippet above to have a common Form (simple dialog box) without consuming the 100% of CPU calling Application.DoEvents(), as Application.Run does. The goal should be to have the snippet above handle messages when arrives, and issue a rendering (releasing the barrier) only when necessary, without trying to get the maximum FPS; there should be the possibility to switch to a strict loop to render as much as possible. How could it be possible? Note: the snippet above must be executed in the Main routine, since the OpenGL context is created on the main thread. Moving the snippet in a separated thread and calling Application.Run is quite unstable and buggy...

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• Optimizing spacing of mesh containing a given set of points

  - by Feynman

  I tried to summarize the this as best as possible in the title. I am writing an initial value problem solver in the most general way possible. I start with an arbitrary number of initial values at arbitrary locations (inside a boundary.) The first part of my program creates a mesh/grid (I am not sure which is the correct nuance), with N points total, that contains all the initial values. My goal is to optimize the mesh such that the spacing is as uniform as possible. My solver seems to work half decently (it needs some more obscure debugging that is not relevant here.) I am starting with one dimension. I intend to generalize the algorithm to an arbitrary number of dimensions once I get it working consistently. I am writing my code in fortran, but feel free to reply with pseudocode or the language of your choice. Allow me to elaborate with an example: Say I am working on a closed interval [1,10] xmin=1 xmax=10 Say I have 3 initial points: xmin, 5 and xmax num_ivc=3 known(num_ivc)=[xmin,5,xmax] //my arrays start at 1. Assume "known" starts sorted I store my mesh/grid points in an array called coord. Say I want 10 points total in my mesh/grid. N=10 coord(10) Remember, all this is arbitrary--except the variable names of course. The algorithm should set coord to {1,2,3,4,5,6,7,8,9,10} Now for a less trivial example: num_ivc=3 known(num_ivc)=[xmin,5.5,xmax or just num_ivc=1 known(num_ivc)=[5.5] Now, would you have 5 evenly spaced points on the interval [1, 5.5] and 5 evenly spaced points on the interval (5.5, 10]? But there is more space between 1 and 5.5 than between 5.5 and 10. So would you have 6 points on [1, 5.5] followed by 4 on (5.5 to 10]. The key is to minimize the difference in spacing. I have been working on this for 2 days straight and I can assure you it is a lot trickier than it sounds. I have written code that only works if N is large only works if N is small only works if it the known points are close together only works if it the known points are far apart only works if at least one of the known points is near a boundary only works if none of the known points are near a boundary So as you can see, I have coded the gamut of almost-solutions. I cannot figure out a way to get it to perform equally well in all possible scenarios (that is, create the optimum spacing.)

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• Avoiding circular project/assembly references in Visual Studio with statically typed dependency conf

  - by svnpttrssn

  First, I want to say that I am not interested in debating about any non-helpful "answers" to my question, with suggestions to putting everything in one assembly, i.e. there is no need for anyone to provide webpages such as the page titled with "Separate Assemblies != Loose Coupling". Now, my question is if it somehow (maybe with some Visual Studio configuration to allow for circular project dependencies?) is possible to use one project/assembly (I am here calling it the "ServiceLocator" assembly) for retrieving concrete implementation classes, (e.g. with StructureMap) which can be referred to from other projects, while it of course is also necessary for the the ServiceLocator itself to refer to other projects with the interfaces and the implementations ? Visual Studio project example, illustrating the kind of dependency structure I am talking about: http://img10.imageshack.us/img10/8838/testingdependencyinject.png Please note in the above picture, the problem is how to let the classes in "ApplicationLayerServiceImplementations" retrieve and instantiate classes that implement the interfaces in "DomainLayerServiceInterfaces". The goal is here to not refer directly to the classes in "DomainLayerServiceImplementations", but rather to try using the project "ServiceLocator" to retrieve such classes, but then the circular dependency problem occurrs... For example, a "UserInterfaceLayer" project/assembly might contain this kind of code: ContainerBootstrapper.BootstrapStructureMap(); // located in "ServiceLocator" project/assembly MyDomainLayerInterface myDomainLayerInterface = ObjectFactory.GetInstance<MyDomainLayerInterface>(); // refering to project/assembly "DomainLayerServiceInterfaces" myDomainLayerInterface.MyDomainLayerMethod(); MyApplicationLayerInterface myApplicationLayerInterface = ObjectFactory.GetInstance<MyApplicationLayerInterface>(); // refering to project/assembly "ApplicationLayerServiceInterfaces" myApplicationLayerInterface.MyApplicationLayerMethod(); The above code do not refer to the implementation projects/assemblies ApplicationLayerServiceImplementations and DomainLayerServiceImplementations, which contain this kind of code: public class MyApplicationLayerImplementation : MyApplicationLayerInterface and public class MyDomainLayerImplementation : MyDomainLayerInterface The "ServiceLocator" project/assembly might contain this code: using ApplicationLayerServiceImplementations; using ApplicationLayerServiceInterfaces; using DomainLayerServiceImplementations; using DomainLayerServiceInterfaces; using StructureMap; namespace ServiceLocator { public static class ContainerBootstrapper { public static void BootstrapStructureMap() { ObjectFactory.Initialize(x => { // The two interfaces and the two implementations below are located in four different Visual Studio projects x.ForRequestedType<MyDomainLayerInterface>().TheDefaultIsConcreteType<MyDomainLayerImplementation>(); x.ForRequestedType<MyApplicationLayerInterface>().TheDefaultIsConcreteType<MyApplicationLayerImplementation>(); }); } } } So far, no problem, but the problem occurs when I want to let the class "MyApplicationLayerImplementation" in the project/assembly "ApplicationLayerServiceImplementations" use the "ServiceLocator" project/assembly for retrieving an implementation of "MyDomainLayerInterface". When I try to do that, i.e. add a reference from "MyApplicationLayerImplementation" to "ServiceLocator", then Visual Studio complains about circular dependencies between projects. Is there any nice solution to this problem, which does not imply using refactoring-unfriendly string based xml-configuration which breaks whenever an interface or class or its namespace is renamed ? / Sven

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• [NEWVERSION]algorithm || method to write prog[UNSOLVED] [closed]

  - by fatai

  I am one of the computer science student. Everyone solve problem with a different or same method, ( but actually I dont know whether they use method or I dont know whether there are such common method to approach problem.) if there are common method, What is it ? If there are different method, which method are you using ? All teacher give us problem which in simple form sometimes, but they donot introduce any approach or method(s) so that we cannot make a decision to choose the method then apply that one to problem , afterward find solution then write code.No help from teacher , push us to find method to solve homework. Ex: my friend is using no method , he says "I start to construct algorithm while I try to write prog." I have found one method when I failed the course, More accurately, my method: When I counter problem in language , I will get more paper and then ; first, input/ output step ; my prog will take this / these there argument(s) and return namely X , ex : in c, input length is not known and at same type , so I must use pointer desired output is in form of package , so use structure second, execution part ; in that step , I am writing all step which are goes to final output ex : in python ; 1.) [ + , [- , 4 , [ * , 1 , 2 ]], 5] 2.) [ + , [- , 4 , 2 ],5 ] 3.) [ + , 2 , 5] 4.) 7 ==> return 7 third, I will write test code ex : in c++ input : append 3 4 5 6 vector_x remove 0 1 desired output vector_x holds : 5 6 now, my other question is ; What is/are other method(s) which have/has been; used to construct class :::: for c++ , python, java used to communicate classes / computers used for solving embedded system problem ::::: for c by other user? Some programmer uses generalized method without considering prog-language(java , perl .. ), what is this method ? Why I wonder , because I learn if you dont costruct algorithm on paper, you may achieve your goal. Like no money no lunch , I can say no algorithm no prog therefore , feel free when you write your own method , a way which is introduced by someone else but you are using and you find it is so efficient

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• Can ASM method-visitors be used with interfaces?

  - by Olaf Mertens

  I need to write a tool that lists the classes that call methods of specified interfaces. It will be used as part of the build process of a large java application consisting of many modules. The goal is to automatically document the dependencies between certain java modules. I found several tools for dependency analysis, but they don't work on the method level, just for packages or jars. Finally I found ASM, that seems to do what I need. The following code prints the method dependencies of all class files in a given directory: import java.io.*; import java.util.*; import org.objectweb.asm.ClassReader; public class Test { public static void main(String[] args) throws Exception { File dir = new File(args[0]); List<File> classFiles = new LinkedList<File>(); findClassFiles(classFiles, dir); for (File classFile : classFiles) { InputStream input = new FileInputStream(classFile); new ClassReader(input).accept(new MyClassVisitor(), 0); input.close(); } } private static void findClassFiles(List<File> list, File dir) { for (File file : dir.listFiles()) { if (file.isDirectory()) { findClassFiles(list, file); } else if (file.getName().endsWith(".class")) { list.add(file); } } } } import org.objectweb.asm.MethodVisitor; import org.objectweb.asm.commons.EmptyVisitor; public class MyClassVisitor extends EmptyVisitor { private String className; @Override public void visit(int version, int access, String name, String signature, String superName, String[] interfaces) { this.className = name; } @Override public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) { System.out.println(className + "." + name); return new MyMethodVisitor(); } } import org.objectweb.asm.commons.EmptyVisitor; public class MyMethodVisitor extends EmptyVisitor { @Override public void visitMethodInsn(int opcode, String owner, String name, String desc) { String key = owner + "." + name; System.out.println(" " + key); } } The Problem: The code works for regular classes only! If the class file contains an interface, visitMethod is called, but not visitMethodInsn. I don't get any info about the callers of interface methods. Any ideas?

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• Google Analytics V2 SDK for Android EasyTracker giving errors

  - by Prince

  I have followed the tutorial for the new Google Analytics V2 SDK for Android located here: https://developers.google.com/analytics/devguides/collection/android/v2/ Unfortunately whenever I go to run the application the reporting is not working and this is the messages that logcat gives me: 07-09 09:13:16.978: W/Ads(13933): No Google Analytics: Library Incompatible. 07-09 09:13:16.994: I/Ads(13933): To get test ads on this device, call adRequest.addTestDevice("2BB916E1BD6BE6407582A429D763EC71"); 07-09 09:13:17.018: I/Ads(13933): adRequestUrlHtml: <html><head><script src="http://media.admob.com/sdk-core-v40.js"></script><script>AFMA_getSdkConstants();AFMA_buildAdURL({"kw":[],"preqs":0,"session_id":"7925570029955749351","u_sd":2,"seq_num":"1","slotname":"a14fd91432961bd","u_w":360,"msid":"com.mysampleapp.sampleapp","js":"afma-sdk-a-v6.0.1","mv":"8013013.com.android.vending","isu":"2BB916E1BD6BE6407582A429D763EC71","cipa":1,"format":"320x50_mb","net":"wi","app_name":"1.android.com.mysampleapp.sampleapp","hl":"en","u_h":592,"carrier":"311480","ptime":0,"u_audio":3});</script></head><body></body></html> 07-09 09:13:17.041: W/ActivityManager(220): Unable to start service Intent { act=com.google.android.gms.analytics.service.START (has extras) }: not found 07-09 09:13:17.049: W/GAV2(13933): Thread[main,5,main]: Connection to service failed 1 07-09 09:13:17.057: W/GAV2(13933): Thread[main,5,main]: Need to call initializea() and be in fallback mode to start dispatch. 07-09 09:13:17.088: D/libEGL(13933): loaded /system/lib/egl/libGLES_android.so 07-09 09:13:17.096: D/libEGL(13933): loaded /vendor/lib/egl/libEGL_POWERVR_SGX540_120.so 07-09 09:13:17.096: D/libEGL(13933): loaded /vendor/lib/egl/libGLESv1_CM_POWERVR_SGX540_120.so 07-09 09:13:17.096: D/libEGL(13933): loaded /vendor/lib/egl/libGLESv2_POWERVR_SGX540_120.so Here is my code (I have redacted some of the code that had to do with httppost, etc.): package com.mysampleapp.sampleapp; import java.io.BufferedReader; import java.io.InputStream; import java.io.InputStreamReader; import java.util.ArrayList; import java.util.List; import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; import org.apache.http.NameValuePair; import org.apache.http.client.HttpClient; import org.apache.http.client.entity.UrlEncodedFormEntity; import org.apache.http.client.methods.HttpPost; import org.apache.http.impl.client.DefaultHttpClient; import org.apache.http.message.BasicNameValuePair; import org.json.JSONArray; import org.json.JSONObject; import com.google.analytics.tracking.android.EasyTracker; import android.app.Activity; import android.app.ProgressDialog; import android.content.DialogInterface; import android.content.DialogInterface.OnCancelListener; import android.content.Intent; import android.content.SharedPreferences; import android.os.AsyncTask; import android.os.Bundle; import android.preference.PreferenceManager; import android.util.Log; import android.view.View; import android.view.View.OnClickListener; import android.widget.ImageView; import android.widget.TextView; public class viewRandom extends Activity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.viewrandom); uservote.setVisibility(View.GONE); new randomViewClass().execute(); } public void onStart() { super.onStart(); EasyTracker.getInstance().activityStart(this); } public void onStop() { super.onStop(); EasyTracker.getInstance().activityStop(this); } }

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• The question about the basics of LINQ to SQL

  - by Alex

  I just started learning LINQ to SQL, and so far I'm impressed with the easy of use and good performance. I used to think that when doing LINQ queries like from Customer in DB.Customers where Customer.Age > 30 select Customer LINQ gets all customers from the database ("SELECT * FROM Customers"), moves them to the Customers array and then makes a search in that Array using .NET methods. This is very inefficient, what if there are hundreds of thousands of customers in the database? Making such big SELECT queries would kill the web application. Now after experiencing how actually fast LINQ to SQL is, I start to suspect that when doing that query I just wrote, LINQ somehow converts it to a SQL Query string SELECT * FROM Customers WHERE Age > 30 And only when necessary it will run the query. So my question is: am I right? And when is the query actually run? The reason why I'm asking is not only because I want to understand how it works in order to build good optimized applications, but because I came across the following problem. I have 2 tables, one of them is Books, the other has information on how many books were sold on certain days. My goal is to select books that had at least 50 sales/day in past 10 days. It's done with this simple query: from Book in DB.Books where (from Sale in DB.Sales where Sale.SalesAmount >= 50 && Sale.DateOfSale >= DateTime.Now.AddDays(-10) select Sale.BookID).Contains(Book.ID) select Book The point is, I have to use the checking part in several queries and I decided to create an array with IDs of all popular books: var popularBooksIDs = from Sale in DB.Sales where Sale.SalesAmount >= 50 && Sale.DateOfSale >= DateTime.Now.AddDays(-10) select Sale.BookID; BUT when I try to do the query now: from Book in DB.Books where popularBooksIDs.Contains(Book.ID) select Book It doesn't work! That's why I think that we can't use thins kinds of shortcuts in LINQ to SQL queries, like we can't use them in real SQL. We have to create straightforward queries, am I right?

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• DriverManager always returns my custom driver regardless of the connection URL

  - by JGB146

  I am writing a driver to act as a wrapper around two separate MySQL connections (to distributed databases). Basically, the goal is to enable interaction with my driver for all applications instead of requiring the application to sort out which database holds the desired data. Most of the code for this is in place, but I'm having a problem in that when I attempt to create connections via the MySQL Driver, the DriverManager is returning an instance of my driver instead of the MySQL Driver. I'd appreciate any tips on what could be causing this and what could be done to fix it! Below is a few relevant snippets of code. I can provide more, but there's a lot, so I'd need to know what else you want to see. First, from MyDriver.java: public MyDriver() throws SQLException { DriverManager.registerDriver(this); } public Connection connect(String url, Properties info) throws SQLException { try { return new MyConnection(info); } catch (Exception e) { return null; } } public boolean acceptsURL(String url) throws SQLException { if (url.contains("jdbc:jgb://")) { return true; } return false; } It is my understanding that this acceptsURL function will dictate whether or not the DriverManager deems my driver a suitable fit for a given URL. Hence it should only be passing connections from my driver if the URL contains "jdbc:jgb://" right? Here's code from MyConnection.java: Connection c1 = null; Connection c2 = null; /** *Constructors */ public DDBSConnection (Properties info) throws SQLException, Exception { info.list(System.out); //included for testing Class.forName("com.mysql.jdbc.Driver").newInstance(); String url1 = "jdbc:mysql://server1.com/jgb"; String url2 = "jdbc:mysql://server2.com/jgb"; this.c1 = DriverManager.getConnection( url1, info.getProperty("username"), info.getProperty("password")); this.c2 = DriverManager.getConnection( url2, info.getProperty("username"), info.getProperty("password")); } And this tells me two things. First, the info.list() call confirms that the correct user and password are being sent. Second, because we enter an infinite loop, we see that the DriverManager is providing new instances of my connection as matches for the mysql URLs instead of the desired mysql driver/connection. FWIW, I have separately tested implementations that go straight to the mysql driver using this exact syntax (al beit only one at a time), and was able to successfully interact with each database individually from a test application outside of my driver.

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• Workflow for statistical analysis and report writing

  - by ws

  Does anyone have any wisdom on workflows for data analysis related to custom report writing? The use-case is basically this: Client commissions a report that uses data analysis, e.g. a population estimate and related maps for a water district. The analyst downloads some data, munges the data and saves the result (e.g. adding a column for population per unit, or subsetting the data based on district boundaries). The analyst analyzes the data created in (2), gets close to her goal, but sees that needs more data and so goes back to (1). Rinse repeat until the tables and graphics meet QA/QC and satisfy the client. Write report incorporating tables and graphics. Next year, the happy client comes back and wants an update. This should be as simple as updating the upstream data by a new download (e.g. get the building permits from the last year), and pressing a "RECALCULATE" button, unless specifications change. At the moment, I just start a directory and ad-hoc it the best I can. I would like a more systematic approach, so I am hoping someone has figured this out... I use a mix of spreadsheets, SQL, ARCGIS, R, and Unix tools. Thanks! PS: Below is a basic Makefile that checks for dependencies on various intermediate datasets (w/ ".RData" suffix) and scripts (".R" suffix). Make uses timestamps to check dependencies, so if you 'touch ss07por.csv', it will see that this file is newer than all the files / targets that depend on it, and execute the given scripts in order to update them accordingly. This is still a work in progress, including a step for putting into SQL database, and a step for a templating language like sweave. Note that Make relies on tabs in its syntax, so read the manual before cutting and pasting. Enjoy and give feedback! http://www.gnu.org/software/make/manual/html%5Fnode/index.html#Top R=/home/wsprague/R-2.9.2/bin/R persondata.RData : ImportData.R ../../DATA/ss07por.csv Functions.R $R --slave -f ImportData.R persondata.Munged.RData : MungeData.R persondata.RData Functions.R $R --slave -f MungeData.R report.txt: TabulateAndGraph.R persondata.Munged.RData Functions.R $R --slave -f TabulateAndGraph.R report.txt

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• Recursive N-way merge/diff algorithm for directory trees?

  - by BobMcGee

  What algorithms or Java libraries are available to do N-way, recursive diff/merge of directories? I need to be able to generate a list of folder trees that have many identical files, and have subdirectories with many similar files. I want to be able to use 2-way merge operations to quickly remove as much redundancy as possible. Goals: Find pairs of directories that have many similar files between them. Generate short list of directory pairs that can be synchronized with 2-way merge to eliminate duplicates Should operate recursively (there may be nested duplicates of higher-level directories) Run time and storage should be O(n log n) in numbers of directories and files Should be able to use an embedded DB or page to disk for processing more files than fit in memory (100,000+). Optional: generate an ancestry and change-set between folders Optional: sort the merge operations by how many duplicates they can elliminate I know how to use hashes to find duplicate files in roughly O(n) space, but I'm at a loss for how to go from this to finding partially overlapping sets between folders and their children. EDIT: some clarification The tricky part is the difference between "exact same" contents (otherwise hashing file hashes would work) and "similar" (which will not). Basically, I want to feed this algorithm at a set of directories and have it return a set of 2-way merge operations I can perform in order to reduce duplicates as much as possible with as few conflicts possible. It's effectively constructing an ancestry tree showing which folders are derived from each other. The end goal is to let me incorporate a bunch of different folders into one common tree. For example, I may have a folder holding programming projects, and then copy some of its contents to another computer to work on it. Then I might back up and intermediate version to flash drive. Except I may have 8 or 10 different versions, with slightly different organizational structures or folder names. I need to be able to merge them one step at a time, so I can chose how to incorporate changes at each step of the way. This is actually more or less what I intend to do with my utility (bring together a bunch of scattered backups from different points in time). I figure if I can do it right I may as well release it as a small open source util. I think the same tricks might be useful for comparing XML trees though.

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• Middleware with generic communication media layer

  - by Tom

  Greetings all, I'm trying to implement middleware (driver) for an embedded device with generic communication media layer. Not sure what is the best way to do it so I'm seeking an advice from more experienced stackoverflow users:). Basically we've got devices around the country communicating with our servers (or a pda/laptop in used in field). Usual form of communication is over TCP/IP, but could be also using usb, RF dongle, IR, etc. The plan is to have object corresponding with each of these devices, handling the proprietary protocol on one side and requests/responses from other internal systems on the other. The thing is how create something generic in between the media and the handling objects. I had a play around with the TCP dispatcher using boost.asio but trying to create something generic seems like a nightmare :). Anybody tried to do something like that? What is the best way how to do it? Example: Device connects to our Linux server. New middleware instance is created (on the server) which announces itself to one of the running services (details are not important). The service is responsible for making sure that device's time is synchronized. So it asks the middleware what is the device's time, driver translates it to device language (protocol) and sends the message, device responses and driver again translates it for the service. This might seem as a bit overkill for such a simple request but imagine there are more complex requests which the driver must translate, also there are several versions of the device which use different protocol, etc. but would use the same time sync service. The goal is to abstract the devices through the drivers to be able to use the same service to communicate with them. Another example: we find out that the remote communications with the device are down. So we send somebody out with PDA, he connects to the device using USB cable. Starts up the application which has the same functionality as the timesync service. Again middleware instance is created (on the PDA) to translate communication between application and the device this time only using USB/serial media not TCP/IP as in previous example. I hope it makes more sense now :) Cheers, Tom

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• string categorization strategies

  - by Andrew Heath

  I'm the one-man dev team on a fledgling military history website. One aspect of the site is a catalog of ~1,200 individual battles, including the nations & formations (regiments, divisions, etc) which took part. The formation information (as well as the other battle info) was manually imported from a series of books by a 10-man volunteer team. The formations were listed in groups with varying formatting and abbreviation patterns. At the time I set up the data collection forms I couldn't think of a good way to process that data... and elected to store it all as strings in the MySQL database and sort it out later. Well, "later" - as it tends to happen - has arrived. :-) Each battle has 2+ records in the database - one for each nation that participated. Each record has a formations text string listing the formations present as the volunteer chose to add them. Some real examples: 39th Grenadier Rgmt, 26th Volksgrenadier Division 2nd Luftwaffe Field Division, 246th Infantry Division 247th Rifle Division, 255th Tank Brigade 2nd Luftwaffe Field Division, SS Cavalry Division 28th Tank Brigade, 158th Rifle Division, 135th Rifle Division, 81st Tank Brigade, 242nd Tank Brigade 78th Infantry Division 3rd Kure Special Naval Landing Force, Tulagi Seaplane Base personnel 1st Battalion 505th Infantry Regiment The ultimate goal is for each individual force to have an ID, so that its participation can be traced throughout the battle database. Formation hierarchy, such as the final item above 1st Battalion (of the) 505th Infantry Regiment also needs to be preserved. In that case, 1st Battalion and 505th Infantry Regiment would be split, but 1st Battalion would be flagged as belonging to the 505th. In database terms, I think I want to pull the formation field out of the current battle info table and create three new tables: FORMATION [id] [name] FORMATION_HIERARCHY [id] [parent] [child] FORMATION_BATTLE [f_id] [battle_id] It's simple to explain, but complicated to enact. What I'm looking for from the SO community is just some tips on how best to tackle this problem. Ideally there's some sort of method to solving this that I'm not aware of. However, as a last resort, I could always code a classification framework and call my volunteers back to sort through 2,500+ records...

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• Formatting Controls in ASP.NET

  - by Brian

  I feel as though this this is a simple question, but can't find an answer anywhere. We've got an interface we're trying to move to an ASP.NET control. It currently looks like: <link rel=""stylesheet"" type=""text/css"" href=""/Layout/CaptchaLayout.css"" /> <script type=""text/javascript"" src=""../../Scripts/vcaptcha_control.js""></script> <div id="captcha_background"> <div id="captcha_loading_area"> <img id="captcha" src="#" alt="" /> </div> <div id="vcaptcha_entry_container"> <input id="captcha_answer" type="text"/> <input id="captcha_challenge" type="hidden"/> <input id="captcha_publickey" type="hidden"/> <input id="captcha_host" type="hidden"/> </div> <div id="captcha_logo_container"></div> </div> However all the examples I see of ASP.NET controls that allow for basical functionality - i.e. public class MyControl : Panel { public MyControl() { } protected override void OnInit(EventArgs e) { ScriptManager.RegisterScript( ... Google script, CSS, etc. ... ); TextBox txt = new TextBox(); txt.ID = "text1"; this.Controls.Add(txt); CustomValidator vld = new CustomValidator(); vld.ControlToValidate = "text1"; vld.ID = "validator1"; this.Controls.Add(vld); } } Don't allow for the detailed layout that we need. Any suggestions on how I can combine layout and functionality and still have a single ASP control we can drop in to pages? The ultimate goal is for users of the control to just drop in: <captcha:CaptchaControl ID="CaptchaControl1" runat="server" Server="http://localhost:51947/" /> and see the working control. Sorry for the basic nature of this one, any help is greatly appreciated.

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• PHP: How to implement a __get-like method for local function variables

  - by Tom Frost

  I'm no stranger to __get(), and have used it to make some very convenient libraries in the past. However, I'm faced with a new challenge (PHP 5.3, abbreviated and simplified my code for this question): <?php namespace test; class View { function __construct($filename, $varArray) { $this->filename = $filename; $this->varArray = $varArray; } function display() { include($this->filename); } function __get($varName) { if (isset($this->varArray[$varName])) return $this->varArray[$varName]; return "?? $varname ??"; } } ?> Above is a very, very simplified system for loading a View. This code would call the view and display it: <?php require_once("View.php"); use test\View; $view = new View("views/myview.php", array("user" => "Tom")); $view->display(); ?> My goal for this code is to allow the view "myview.php" to contain code like this: <p> Hello <?php echo $user; ?>! Your E-mail is <?php echo $email; ?> </p> And, used with the above code, this would output "Hello Tom! Your E-mail is ?? email ??" However, this won't work. The view is being included within a class method, so when it refers to $user and $email, it's looking for local function variables -- not variables belonging to the View class. For this reason, __get never gets triggered. I could change all my view's variables to things like $this-user and $this-email, but that would be a messy and unintuitive solution. I'd love to find a way where I can reference variables directly WITHOUT having PHP throw an error when an undefined variable is used. Thoughts? Is there a clean way to do this, or am I forced to resort to hacky solutions?

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• use jquery to toggle disabled state with a radio button

  - by hbowman

  I want to toggle two radio buttons and select fields based on which radio button is selected. I have the jQuery working, but want to know if there is a way to make it more efficient. Seems like quite a few lines for the simple goal I am trying to achieve. Here are the requirements: when the page loads, #aircraftType should be checked and #aircraftModelSelect should be grayed out (right now, the "checked" is being ignored by Firefox). If the user clicks either #aircraftType or #aircraftModel, the opposite select field should become disabled (if #aircraftModel is checked, #aircraftTypeSelect should be disabled, and vise versa). Any help on optimizing this code is appreciated. Code is up on jsfiddle too: http://jsfiddle.net/JuRKn/ $("#aircraftType").attr("checked"); $("#aircraftModel").removeAttr("checked"); $("#aircraftModelSelect").attr("disabled","disabled").addClass("disabled"); $("#aircraftType").click(function(){ $("#aircraftModelSelect").attr("disabled","disabled").addClass("disabled"); $("#aircraftTypeSelect").removeAttr("disabled").removeClass("disabled"); }); $("#aircraftModel").click(function(){ $("#aircraftTypeSelect").attr("disabled","disabled").addClass("disabled"); $("#aircraftModelSelect").removeAttr("disabled").removeClass("disabled"); }); HTML <div class="aircraftType"> <input type="radio" id="aircraftType" name="aircraft" checked /> <label for="aircraftType">Aircraft Type</label> <select size="6" multiple="multiple" id="aircraftTypeSelect" name="aircraftType"> <option value="">Light Jet</option> <option value="">Mid-Size Jet</option> <option value="">Super-Mid Jet</option> <option value="">Heavy Jet</option> <option value="">Turbo-Prop</option> </select> </div> <div class="aircraftModel"> <input type="radio" id="aircraftModel" name="aircraft" /> <label for="aircraftModel">Aircraft Model</label> <select size="6" multiple="multiple" id="aircraftModelSelect" name="aircraftModel"> <option value="">Astra SP</option> <option value="">Beechjet 400</option> <option value="">Beechjet 400A</option> <option value="">Challenger 300</option> <option value="">Challenger 600</option> <option value="">Challenger 603</option> <option value="">Challenger 604</option> <option value="">Challenger 605</option> <option value="">Citation Bravo</option> </select> </div>

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• Selecting an element based on text and attribute of its sibling, using Xpath

  - by Adam Asham

  Looking at the document, the goal is to select the second cell from the second row, in the first table. I've created the following expression: //row/td[2]/text()[td[@class="identifier"]/span[text()="identifier"]] but it does not return any rows. Unfortunately I do not see what's wrong. To me, it looks alright. The expression should: select the text in the second cell in any row where the text of a span equals to "identifier" and the span is located in cell with a "identifier" class I'd appreciate it if you could point out what I'm doing wrong. Sample XML document: <?xml version="1.0"?> <html> <table class="first"> <tr> <td>row 1, cell 1</td> <td>row 1, cell 2</td> </tr> <tr> <td class="identifier"> <span>identifier</span> </td> <td> foo <span>ignore</span> bar </td> </tr> <tr> <td>row 3, cell 1</td> <td>row 3, cell 2</td> </tr> </table> <table class="second"> <tr> <td>row 1, cell 1</td> <td>row 1, cell 2</td> </tr> <tr> <td class="identifier"> <span>not an identifier</span> </td> <td> not a target </td> </tr> <tr> <td>row 3, cell 1</td> <td>row 3, cell 2</td> </tr> </table> </html>

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• Share a "deep link" from a Windows 8/WinRT application

  - by Dave Parker

  I have searched using many different terms and phrases, and waded through many pages of results, but I have (remarkably) not seen anyone else addressing, even asking, about, this issue. So here goes... Ultimate Goal: Allow a user viewing a content-based page (may contain both text and images) within a Windows Store app to share that content with someone else. Description I am working on taking a fair amount of content and making it available for browsing/navigating as a Windows 8/WinRT/Windows Store (we need a consistent name here) application. One of the desired features is to take advantage of the Share Charm, such that someone viewing a page could share that page with someone else. The ideal behavior is for the application to implement the Share Source contract which would share an email message that contained some explanatory text, a link to get the app from the Windows Store, and a "deep link" into the shared page in the application. Solutions Considered We had originally looked at just generating a PDF representation of the page, but there are very few external libraries that would work under WinRT, and having to include externally licensed code would be problematic as well. Writing our own PDF generation code would out of scope. We have also considered generating a Word document or PowerPoint slide using OpenXML, but again, we run up against the limitaions of WinRT. In this case, it is highly unlikely the OpenXML SDK is useable in a WinRT application. Another thought was to pre-generate all of the pages as .pdf files, store them as resources, and when the Share Charm is invoked, share the .pdf file associated with the current page. The problem here is the application will have at least 150 content pages, and depending on how we break the content down, up to over 600. This would likely cause serious bloat. Where We Are At Thus we have come to sharing URIs. From what I can tell, though, the "deep linking" feature is only intended for use on Secondary Tiles tied to your application. Another avenue I considered was registering a protocol like, "my-special-app:" with the OS and having it fire up the application but that would require HKCR registry access, which is outside the WinRT sandbox. If it matters, we are leaning towards an HTML/JS application, rather than XAML/C#, because the converted content will all be in HTML and the WebView control in WinRT is fairly limited. This decision is not yet final, though. Conclusion So, is this possible, and if so, how would it be done or where can I find documentation on it? Thanks, Dave Parker

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• A shortest path problem with superheroes and intergalactic journeys

  - by Dman

  You are a super-hero in the year 2222 and you are faced with this great challenge: starting from your home planet Ilop you must try to reach Acinhet or else your planet will be destroyed by evil green little monsters. To do this you are given a map of the universe: there are N planets and M inter-planetary connections ( bidirectional ) that bind these planets. Each connection requires a certain time and a certain amount of fuel in order for you to cover the connection from one planet to another. The total time spent going from one planet to another is obtained by multiplying the time past to cover each connection between all the planets you go through. There are some "key planets", that allow you to refuel if you arrive on those certain "key planets". A "key planet" is the planet with the property that if it disappears the road between at least two planets would be lost.(In the example posted below with the input/output files such a "key planet" is 2 because without it the road to 7 would be lost) When you start your mission you are given the possibility of choosing between K ships each with its own maximum fuel capacity. The goal is to find the SHORTEST TIME CONSUMING path but also choose the ship with the minimum fuel capacity that can cover that shortest path(this means that if more ships can cover the shortest path you choose the one with the minimum fuel capacity). Because the minimum time can be a rather large number (over long long int) you are asked to provide only the last 6 digits of the number. For a better understanding of the task, here is an example of input/output files: INPUT: mission.in 7 8 6 1 4 6 5 9 8 7 10 1 2 7 8 1 4 14 9 1 5 3 1 2 3 1 2 2 7 7 1 3 4 2 2 4 6 4 1 5 6 3 7 On the first line (in order): N M K On the second line :the number for the starting planet and the finishing planet On the third line :K numbers that represent the capacities of the ships you can choose from Then you have M lines, all of them have the same structure: Xi Yi Ti Fi-which means that there is a connection between Xi and Yi and you can cover the distance from Xi to Yi in Ti time and with a Fi fuel consumption. OUTPUT:mission.out 000014 8 1 2 3 4 On the first line:the minimum time and fuel consumption; On the second line :the path Restrictions: 2 = N = 1 000 1 = M = 30 000 1 = K = 10 000 Any suggestions or ideas of how this problem might be solved would be most welcomed.

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• Are there programs that iteratively write new programs?

  - by chris

  For about a year I have been thinking about writing a program that writes programs. This would primarily be a playful exercise that might teach me some new concepts. My inspiration came from negentropy and the ability for order to emerge from chaos and new chaos to arise out of order in infinite succession. To be more specific, the program would start by writing a short random string. If the string compiles the programs will log it for later comparison. If the string does not compile the program will try to rewrite it until it does compile. As more strings (mini 'useless' programs) are logged they can be parsed for similarities and used to generate a grammar. This grammar can then be drawn on to write more strings that have a higher probability of compilation than purely random strings. This is obviously more than a little silly, but I thought it would be fun to try and grow a program like this. And as a byproduct I get a bunch of unique programs that I can visualize and call art. I'll probably write this in Ruby due to its simple syntax and dynamic compilation and then I will visualize in processing using ruby-processing. What I would like to know is: Is there a name for this type of programming? What currently exists in this field? Who are the primary contributors? BONUS! - In what ways can I procedurally assign value to output programs beyond compiles(y/n)? I may want to extend the functionality of this program to generate a program based on parameters, but I want the program to define those parameters through running the programs that compile and assigning meaning to the programs output. This question is probably more involved than reasonable for a bonus, but if you can think of a simple way to get something like this done in less than 23 lines or one hyperlink, please toss it into your response. I know that this is not quite meta-programming and from the little I know of AI and generative algorithms they are usually more goal oriented than what I am thinking. What would be optimal is a program that continually rewrites and improves itself so I don't have to ^_^

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• How to access and work with XML from API in C#

  - by Jarek

  My goal is to pull XML data from the API and load it to a sql server database. The frist step I'm attempting here is to access the data and display it. Once I get this to work I'll loop through each row and insert the values into a sql server database. When I try to run the code below nothing happens and when I paste the url directly into the browser I get this error "2010-03-08 04:24:17 Wallet exhausted: retry after 2010-03-08 05:23:58. 2010-03-08 05:23:58" To me it seems that every iteration of the foreach loop makes a call to the site and I get blocked for an hour. Am I retrieving data from the API in an incorrect manner? Is there some way to load the data into memory or an array then loop through that? Here's the bit of code I hacked together. using System; using System.Data.SqlClient; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using System.Xml; using System.Data; public partial class _Default : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { try { string userID = "123"; string apiKey = "abc456"; string characterID = "789"; string url = "http://api.eve-online.com/char/WalletTransactions.xml.aspx?userID=" + userID + "&apiKey=" + apiKey + "&characterID=" + characterID; XmlDocument xmldoc = new XmlDocument(); xmldoc.Load(url); XmlNamespaceManager xnm1 = new XmlNamespaceManager(xmldoc.NameTable); XmlNodeList nList1 = xmldoc.SelectNodes("result/rowset/row", xnm1); foreach (XmlNode xNode in nList1) { Response.Write(xNode.InnerXml + "<br />"); } } catch (SqlException em) { Response.Write(em.Message); } } } Here's a sample of the xml <eveapi version="2"> <currentTime>2010-03-06 17:38:35</currentTime> <result> <rowset name="transactions" key="transactionID" columns="transactionDateTime,transactionID,quantity,typeName,typeID,price,clientID,clientName,stationID,stationName,transactionType,transactionFor"> <row transactionDateTime="2010-03-06 17:16:00" transactionID="1343566007" quantity="1" typeName="Co-Processor II" typeID="3888" price="1122999.00" clientID="1404318579" clientName="unseenstrike" stationID="60011572" stationName="Osmeden IX - Moon 6 - University of Caille School" transactionType="sell" transactionFor="personal" /> <row transactionDateTime="2010-03-06 17:15:00" transactionID="1343565894" quantity="1" typeName="Co-Processor II" typeID="3888" price="1150000.00" clientID="1404318579" clientName="unseenstrike" stationID="60011572" stationName="Osmeden IX - Moon 6 - University of Caille School" transactionType="sell" transactionFor="personal" /> </rowset> </result> <cachedUntil>2010-03-06 17:53:35</cachedUntil> </eveapi>

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• What am I not getting about this abstract class implementation?

  - by Schnapple

  PREFACE: I'm relatively inexperienced in C++ so this very well could be a Day 1 n00b question. I'm working on something whose long term goal is to be portable across multiple operating systems. I have the following files: Utilities.h #include <string> class Utilities { public: Utilities() { }; virtual ~Utilities() { }; virtual std::string ParseString(std::string const& RawString) = 0; }; UtilitiesWin.h (for the Windows class/implementation) #include <string> #include "Utilities.h" class UtilitiesWin : public Utilities { public: UtilitiesWin() { }; virtual ~UtilitiesWin() { }; virtual std::string ParseString(std::string const& RawString); }; UtilitiesWin.cpp #include <string> #include "UtilitiesWin.h" std::string UtilitiesWin::ParseString(std::string const& RawString) { // Magic happens here! // I'll put in a line of code to make it seem valid return ""; } So then elsewhere in my code I have this #include <string> #include "Utilities.h" void SomeProgram::SomeMethod() { Utilities *u = new Utilities(); StringData = u->ParseString(StringData); // StringData defined elsewhere } The compiler (Visual Studio 2008) is dying on the instance declaration c:\somepath\somecode.cpp(3) : error C2259: 'Utilities' : cannot instantiate abstract class due to following members: 'std::string Utilities::ParseString(const std::string &)' : is abstract c:\somepath\utilities.h(9) : see declaration of 'Utilities::ParseString' So in this case what I'm wanting to do is use the abstract class (Utilities) like an interface and have it know to go to the implemented version (UtilitiesWin). Obviously I'm doing something wrong but I'm not sure what. It occurs to me as I'm writing this that there's probably a crucial connection between the UtilitiesWin implementation of the Utilities abstract class that I've missed, but I'm not sure where. I mean, the following works #include <string> #include "UtilitiesWin.h" void SomeProgram::SomeMethod() { Utilities *u = new UtilitiesWin(); StringData = u->ParseString(StringData); // StringData defined elsewhere } but it means I'd have to conditionally go through the different versions later (i.e., UtilitiesMac(), UtilitiesLinux(), etc.) What have I missed here?

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• Text Obfuscation using base64_encode()

  - by user271619

  I'm playing around with encrypt/decrypt coding in php. Interesting stuff! However, I'm coming across some issues involving what text gets encrypted into. Here's 2 functions that encrypt and decrypt a string. It uses an Encryption Key, which I set as something obscure. I actually got this from a php book. I modified it slightly, but not to change it's main goal. I created a small example below that anyone can test. But, I notice that some characters show up as the "encrypted" string. Characters like "=" and "+". Sometimes I pass this encrypted string via the url. Which may not quite make it to my receiving scripts. I'm guessing the browser does something to the string if certain characters are seen. I'm really only guessing. is there another function I can use to ensure the browser doesn't touch the string? or does anyone know enough php bas64_encode() to disallow certain characters from being used? I'm really not going to expect the latter as a possibility. But, I'm sure there's a work-around. enjoy the code, whomever needs it! define('ENCRYPTION_KEY', "sjjx6a"); function encrypt($string) { $result = ''; for($i=0; $i<strlen($string); $i++) { $char = substr($string, $i, 1); $keychar = substr(ENCRYPTION_KEY, ($i % strlen(ENCRYPTION_KEY))-1, 1); $char = chr(ord($char)+ord($keychar)); $result.=$char; } return base64_encode($result)."/".rand(); } function decrypt($string){ $exploded = explode("/",$string); $string = $exploded[0]; $result = ''; $string = base64_decode($string); for($i=0; $i<strlen($string); $i++) { $char = substr($string, $i, 1); $keychar = substr(ENCRYPTION_KEY, ($i % strlen(ENCRYPTION_KEY))-1, 1); $char = chr(ord($char)-ord($keychar)); $result.=$char; } return $result; } echo $encrypted = encrypt("reaplussign.jpg"); echo "<br>"; echo decrypt($encrypted);

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• Classes to Entities; Like-class inheritence problems

  - by Stacey

  Beyond work, some friends and I are trying to build a game of sorts; The way we structure some of it works pretty well for a normal object oriented approach, but as most developers will attest this does not always translate itself well into a database persistent approach. This is not the absolute layout of what we have, it is just a sample model given for sake of representation. The whole project is being done in C# 4.0, and we have every intention of using Entity Framework 4.0 (unless Fluent nHibernate can really offer us something we outright cannot do in EF). One of the problems we keep running across is inheriting things in database models. Using the Entity Framework designer, I can draw the same code I have below; but I'm sure it is pretty obvious that it doesn't work like it is expected to. To clarify a little bit; 'Items' have bonuses, which can be of anything. Therefore, every part of the game must derive from something similar so that no matter what is 'changed' it is all at a basic enough level to be hooked into. Sounds fairly simple and straightforward, right? So then, we inherit everything that pertains to the game from 'Unit'. Weights, Measures, Random (think like dice, maybe?), and there will be other such entities. Some of them are similar, but in code they will each react differently. We're having a really big problem with abstracting this kind of thing into a database model. Without 'Enum' support, it is proving difficult to translate into multiple tables that still share a common listing. One solution we've depicted is to use a 'key ring' type approach, where everything that attaches to a character is stored on a 'Ring' with a 'Key', where each Key has a Value that represents a type. This works functionally but we've discovered it becomes very sluggish and performs poorly. We also dislike this approach because it begins to feel as if everything is 'dumped' into one class; which makes management and logical structure difficult to adhere to. I was hoping someone else might have some ideas on what I could do with this problem. It's really driving me up the wall; To summarize; the goal is to build a type (Unit) that can be used as a base type (Table per Type) for generic reference across a relatively global scope, without having to dump everything into a single collection. I can use an Interface to determine actual behavior so that isn't too big of an issue. This is 'roughly' the same idea expressed in the Entity Framework.

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• Collision point of 2 curves in a 3d-room

  - by Frank

  Hello, i am programming a small game for quite some time. We started coding a small FPS-Shooter inside of a project at school to get a bit experience using directX. I dont know why, but i couldnt stop the project and started programming at home aswell. At the moment i am trying to create some small AI. Of cause thats definatlly not easy, but thats my personal goal anyways. The topic could prolly fill multiple books hehe. I've got the walking part of my bots done so far. They walk along a scriped path. I am not working on the "aiming" of the bots. While programming that i hit on some math problem i couldnt solve yet. I hope of your input on this to help me get further. Concepts, ideas and everything else are highly appreciated. Problem: Calculate the position (D3DXVECTOR3) where the curve of the projectile (depends on gravity, speed), hit the curved of the enemys walking path (depends on speed). We assume that the enemy walks in a constant line. Known variables: float projectilSpeed = 2000 m/s //speed of the projectile per second float gravitation = 9.81 m/s^2 //of cause the gravity lol D3DXVECTOR3 targetPosition //position of the target stored in a vector (x,y,z) D3DXVECTOR3 projectilePosition //position of the projectile D3DXVECTOR3 targetSpeed //stores the change of the targets position in the last second Variabledefinition ProjectilePosition at time of collision = ProjectilePos_t TargetPosition at time of collision = TargetPos_t ProjectilePosition at time 0, now = ProjectilePos_0 TargetPosition at time 0, now = TargetPos_0 Time to impact = t Aim-angle = theta My try: Found a formular to calculate "drop" (Drop of the projectile based on the gravity) on Wikipedia: float drop = 0.5f * gravity * t * t The speed of the projectile has a horizontal and a vertical part.. Found a formular for that on wikipedia aswell: ProjectilVelocity.x = projectilSpeed * cos(theta) ProjectilVelocity.y = projectilSpeed * sin(theta) So i would assume this is true for the projectile curve: ProjectilePos_t.x = ProjectilePos_0.x + ProjectileSpeed * t ProjectilePos_t.y = ProjectilePos_0.y + ProjectileSpeed * t + 0.5f * gravity * t * t ProjectilePos_t.z = ProjectilePos_0.z + ProjectileSpeed * t The target walk with a constant speed, so we can determine his curve by this: TargetPos_t = TargetPos_0 + TargetSpeed * D3DXVECTOR3(t, t, t) Now i dont know how to continue. I have to solve it somehow to get a hold on the time to impact somehow. As a basic formular i could use: float time = distanz / projectileSpeed But that wouldnt be truly correct as it would assume a linear "Trajectory". We just find this behaivor when using a rocket. I hope i was able to explain the problem as much as possible. If there are questions left, feel free to ask me! Greets from germany, Frank

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