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Search found 143 results on 6 pages for 'johannes ernst'.

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  • Map Reduce Frameworks/Infrastructure

    - by Johannes Rudolph
    Map Reduce is a pattern that seems to get a lot of traction lately and I start to see it manifest in one of my projects that is focused on an event processing pipeline (iPhone Accelerometer and GPS data). I needed to built a lot of infrastructure for this project, in fact it overweighs the logic code interacting with it by 2x. Some of the components I built where EventProcessors (with in- and output plus buffering, timing etc.), multiplexers and aggregators. This leads me to my question what the "common" required infrastrucutre for map reduce is. Since I am working with .Net a lot I can see map reduce infrastructure built into the Framework and language constructs. Functional languages support this paradigm per se. It seems every language can be used with map reduce, some have better support than others, others again are built around that concept (e.g. Go). And there are Frameworks like Apache Hadoop to support map reduce.

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  • Xpath: Selecting all of an element type?

    - by Johannes
    I'm just starting to learn Xpath, I'm trying to write a line of code that will select all of the actors in EACH movie parent (through Java!). Below, I have an example of one movie, but there are multiple <Movie> elements, each with <Actor> elements. <Movie Genre = 'Other'> <Title>Requiem For A Dream</Title> <ReleaseYear>2000</ReleaseYear> <Director>Darren Aronofsky</Director> <Actor Character = 'Sara Goldfarb'>Ellen Burstyn</Actor> <Actor Character = 'Harry Goldfarb'>Jared Leto</Actor> <Actor Character = 'Marion Silver'>Jennifer Connelly</Actor> <Actor Character = 'Tyrone C. Love'>Marlon Wayans</Actor> </Movie> Currently, I can only select the first <Actor> element of each <Movie> element -- is it possible to select all of them without using a for loop? Here is my current line of code that displays the first <Actor> element of every <Movie> element: System.out.println("Starring: " + xpath.evaluate("Actor", movieNode) + " as " + xpath.evaluate("Actor/@Character", movieNode) + "\n"); Any and all help if much appreciated!

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  • Avoid being blocked by web mail companies for mass/bulk emailing ?

    - by Johannes
    Our company is sending out a lot of emails per day and planning to send even more in future. (thousands) Also there are mass mailouts as well in the ten thousands every now and then. Anybody has experience with hotmail, yahoo (web.de, gmx.net) and similar webmail companies blocking your emails because "too many from the same source in a period of time" have been sent to them? What can be done about it? Spreading email mailouts over a whole day/night? At what rate? (we are talking about legal emailing just to make sure...)

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  • Chipmunk physics: Velocity question

    - by Johannes Jensen
    I'm making an iPhone game where the main actor is a ball that rolls depending on the device's accelerometer rotation. I haven't started on this part of the coding yet, but I was wondering if you guys had a nice way of solving this: I tried looking a little into chipmunk, and I noticed that bodies have the property v, which is a point containing x and y velocities. I was thinking it'd be a bad idea to just do like: playerBody->v = ccp(accelerometer.x * 5, playerBody->v.y); because it'd just roll up of walls and stuff, is there a better solution to do this?

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  • Should I use uint in C# for values that can't be negative?

    - by Johannes Rössel
    I have just tried implementing a class where numerous length/count properties, etc. are uint instead of int. However, while doing so I noticed that it's actually painful to do so, like as if no one actually wants to do that. Nearly everything that hands out an integral type returns an int, therefore requiring casts in several points. I wanted to construct a StringBuffer with its buffer length defaulted to one of the fields in that class. Requires a cast too. So I wondered whether I should just revert to int here. I'm certainly not using the entire range anyway. I just thought since what I'm dealing with there simply can't be negative (if it was, it'd be an error) it'd be a nice idea to actually use uint. P.S.: I saw this question and this at least explains why the framework itself always uses int but even in own code it's actually cumbersome to stick to uint which makes me think it apparently isn't really wanted.

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  • Different results when applying function to equal values

    - by Johannes Stiehler
    I'm just digging a bit into Haskell and I started by trying to compute the Phi-Coefficient of two words in a text. However, I ran into some very strange behaviour that I cannot explain. After stripping everything down, I ended up with this code to reproduce the problem: let sumTup = (sumTuples°concat) frequencyLists let sumFixTup = (138, 136, 17, 204) putStrLn (show ((138, 136, 17, 204) == sumTup)) putStrLn (show (phi sumTup)) putStrLn (show (phi sumFixTup)) This outputs: True NaN 0.4574206676616167 So although the sumTupand sumFixTup show as equal, they behave differently when passed to phi. The definition of phi is: phi (a, b, c, d) = let dividend = fromIntegral(a * d - b * c) divisor = sqrt(fromIntegral((a + b) * (c + d) * (a + c) * (b + d))) in dividend / divisor

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  • ios 4.1 doesn't call Phonegap API

    - by Johannes Klauß
    I'm working on a cross platform app for Android 2.2 and iOS 4.1 (dev devices). On Android everything works fine (accelerometer and geolocation) even if it's a little laggy. On iOS it's way more smooth, but he doesn't call the Phonegap functions. That's my JS code: var watchID = null; var shaking = { left: false, right: true }; function startWatch() { // Update acceleration every 100 ms var options = { frequency : 100 }; watchID = navigator.accelerometer.watchAcceleration(function(acceleration) { if(acceleration.x < -8) { shaking.left = true; } else if(acceleration.x > 8) { shaking.right = true; } if(shaking.left && shaking.right) { navigator.notification.vibrate(500); shaking.left = false; shaking.right = false; stopWatch(); } }, null, options); } I just call it with <a href="" onclick="startWatch();">start Accel</a> But iOS doesn't react at all. Is there any special call you need to do in iOS?

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  • Shutting down a WPF application from App.xaml.cs

    - by Johannes Rössel
    I am currently writing a WPF application which does command-line argument handling in App.xaml.cs (which is necessary because the Startup event seems to be the recommended way of getting at those arguments). Based on the arguments I want to exit the program at that point already which, as far as I know, should be done in WPF with Application.Current.Shutdown() or in this case (as I am in the current application object) probably also just this.Shutdown(). The only problem is that this doesn't seem to work right. I've stepped through with the debugger and code after the Shutdown() line still gets executed which leads to errors afterwards in the method, since I expected the application not to live that long. Also the main window (declared in the StartupUri attribute in XAML) still gets loaded. I've checked the documentation of that method and found nothing in the remarks that tell me that I shouldn't use it during Application.Startup or Application at all. So, what is the right way to exit the program at that point, i. e. the Startup event handler in an Application object?

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  • how to get the size of a C global array into an assembly program written for the avr architecture co

    - by johannes
    I have a .c file with the following uint8_t buffer[32] I have a .S file where I want to do the following cpi r29, buffer+sizeof(buffer) The second argument for cpi muste be an imidiate value not a location. But unfortunetly sizeof() is a c operator. Both files, are getting compiled to seperate object files and linked afterwards. If I do avr-objdump -x file.c. Amongst other things, I get the size of the buffer. So it is already available in the object file. How do I access the size of the buffer in my assembly file at compile time?

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  • How to access hidden template in unnamed namespace?

    - by Johannes Schaub - litb
    Here is a tricky situation, and i wonder what ways there are to solve it namespace { template <class T> struct Template { /* ... */ }; } typedef Template<int> Template; Sadly, the Template typedef interferes with the Template template in the unnamed namespace. When you try to do Template<float> in the global scope, the compiler raises an ambiguity error between the template name and the typedef name. You don't have control over either the template name or the typedef-name. Now I want to know whether it is possible to: Create an object of the typedefed type Template (i.e Template<int>) in the global namespace. Create an object of the type Template<float> in the global namespace. You are not allowed to add anything to the unnamed namespace. Everything should be done in the global namespace. This is out of curiosity because i was wondering what tricks there are for solving such an ambiguity. It's not a practical problem i hit during daily programming.

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  • Graphical Sudo for Mac OSX

    - by Johannes
    Hi. I'm designing a little software in java. Don't know the term/definition to what I'm doing, but I'm prompting commands from java to the terminal. Something like this: Process process = Runtime.getRuntime().exec("command"); I've done this before in linux, and I used the gksudo for commands that required root password. Is there any "gksudo" in os x? Any graphical popup asking for root password. Thanks =)

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  • Predefining C Array

    - by Johannes Jensen
    In C, when defining an array I can do the following: int arr[] = {5, 2, 9, 8}; And thus I defined it and filled it up, but how do I define it in my .h file, and then fill it in my .c? Like do something like int arr[]; arr = {5, 2, 9, 8}; I'm pretty new to C, not sure how it would look any suggestions?

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  • Objective-C Using Accelerometer (iPhone)

    - by Johannes Jensen
    I have a class called MainGame, which is defined like this in my .h: @interface MainGame : Renderer <UIAccelerometerDelegate> Then later in my .m I have this: - (void) accelerometer: (UIAccelerometer *)accelerometer didAccelerate: (UIAcceleration *)acceleration { // here I would read values like accelerometer.x NSLog(@"accelerated!!1"); } Am I doing it right? Currently I'm only testing in iPhone simulator, I'm going to buy the apple $99 developer thing soon. It doesn't log "accelerated!!1", but I'm guessing that's because I'm not running it on an actual device yet?

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  • Correctly Applying an Open Source License

    - by Johannes Rudolph
    My question consists of multiple points that are inherently related, I apologize for that. I tried splitting it up a little more, but I would keep repeating myself. What exactly is required to apply an open source license to a code base that is my Intellectual Property? A lot of Open Source projects include a full copy of the license somewhere in a root directory but do also have some sort of file header including a license description, disclaimer and a copyright notice. Is that really necessary or does it depend on the license type? If someone else contributes changes to this file, does he need to be named in the copyright notice too?

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  • TFS How does merging work?

    - by Johannes Rudolph
    I have a release branch (RB, starting at C5) and a changeset on trunk (C10) that I now want to merge onto RB. The file has changes at C3 (common to both), one in CS 7 on RB, and one in C9 (trunk) and one in C10). So the history for my changed file looks like this: RB: C5 -> C7 Trunk: C3 -> C9 -> C10 When I merge C10 from trunk to RB, I'd expect to see a merge window showing me C10 | C3 | C7 since C3 is the common ancestor revision and C10 and C7 are the tips of my two branches respectively. However, my merge tool shows me C10 | C9 | C7. My merge tool is configured to show %1(OriginalFile)|%3(BaseFile)|%2(Modified File), so this tells me TFS chose C9 as the base revision. This is totally unexpected and completely contrary to the way I'm used to merges working in Mercurial or Git. Did I get something wrong or is TFS trying to drive me nuts with merging? Is this the default TFS Merge behavior? If so, can you provide insight into why they chose to implement it this way? I'm using TFS 2008 with VS2010 as a Client.

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  • Usage of Assert.Inconclusive

    - by Johannes Rudolph
    Hi, Im wondering how someone should use Assert.Inconclusive(). I'm using it if my Unit test would be about to fail for a reason other than what it is for. E.g. i have a method on a class that calculates the sum of an array of ints. On the same class there is also a method to calculate the average of the element. It is implemented by calling sum and dividing it by the length of the array. Writing a Unit test for Sum() is simple. However, when i write a test for Average() and Sum() fails, Average() is likely to fail also. The failure of Average is not explicit about the reason it failed, it failed for a reason other than what it should test for. That's why i would check if Sum() returns the correct result, otherwise i Assert.Inconclusive(). Is this to be considered good practice? What is Assert.Inconclusive intended for? Or should i rather solve the previous example by means of an Isolation Framework?

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  • Function with parameter type that has a copy-constructor with non-const ref chosen?

    - by Johannes Schaub - litb
    Some time ago I was confused by the following behavior of some code when I wanted to write a is_callable<F, Args...> trait. Overload resolution won't call functions accepting arguments by non-const ref, right? Why doesn't it reject in the following because the constructor wants a Test&? I expected it to take f(int)! struct Test { Test() { } // I want Test not be copyable from rvalues! Test(Test&) { } // But it's convertible to int operator int() { return 0; } }; void f(int) { } void f(Test) { } struct WorksFine { }; struct Slurper { Slurper(WorksFine&) { } }; struct Eater { Eater(WorksFine) { } }; void g(Slurper) { } void g(Eater) { } // chooses this, as expected int main() { // Error, why? f(Test()); // But this works, why? g(WorksFine()); } Error message is m.cpp: In function 'int main()': m.cpp:33:11: error: no matching function for call to 'Test::Test(Test)' m.cpp:5:3: note: candidates are: Test::Test(Test&) m.cpp:2:3: note: Test::Test() m.cpp:33:11: error: initializing argument 1 of 'void f(Test)' Can you please explain why one works but the other doesn't?

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  • XMLEncoder and PersistenceDelegate

    - by Johannes Rössel
    I'm trying to use XMLEncoder to write an object graph (tree in my case) to a file. However, one class contained in it is not actually a Java bean and I don't particularly like making its guts publicly accessible. It's accessed more like a list and has appropriate add methods. I've already written a custom PersistenceDelegate to deal with that. However, is there any way for XMLEncoder to pick it up on its own or do I really need to add it whenever I use an encoder to write a graph that may contain said class?

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  • Combining two UPDATE Commands - Performance ?

    - by Johannes
    If I want to update two rows in a MySQL table, using the following two command: UPDATE table SET Col = Value1 WHERE ID = ID1 UPDATE table SET Col = Value2 WHERE ID = ID2` I usually combine them into one command, so that I do not to have to contact the MySQL server twice from my C client: UPDATE table SET Col = IF( ID = ID1 , Value1 , Value2) WHERE ID=ID1 OR ID=ID2 Is this really a performance gain? Background Information: I am using a custom made fully C written high-performance heavily loaded webserver.

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  • C callback functions defined in an unnamed namespace?

    - by Johannes Schaub - litb
    Hi all. I have a C++ project that uses a C bison parser. The C parser uses a struct of function pointers to call functions that create proper AST nodes when productions are reduced by bison: typedef void Node; struct Actions { Node *(*newIntLit)(int val); Node *(*newAsgnExpr)(Node *left, Node *right); /* ... */ }; Now, in the C++ part of the project, i fill those pointers class AstNode { /* ... */ }; class IntLit : public AstNode { /* ... */ }; extern "C" { Node *newIntLit(int val) { return (Node*)new IntLit(val); } /* ... */ } Actions createActions() { Actions a; a.newIntLit = &newIntLit; /* ... */ return a; } Now the only reason i put them within extern "C" is because i want them to have C calling conventions. But optimally, i would like their names still be mangled. They are never called by-name from C code, so name mangling isn't an issue. Having them mangled will avoid name conflicts, since some actions are called like error, and the C++ callback function has ugly names like the following just to avoid name clashes with other modules. extern "C" { void uglyNameError(char const *str) { /* ... */ } /* ... */ } a.error = &uglyNameError; I wondered whether it could be possible by merely giving the function type C linkage extern "C" void fty(char const *str); namespace { fty error; /* Declared! But i can i define it with that type!? */ } Any ideas? I'm looking for Standard-C++ solutions.

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  • Objective-C subclasses question

    - by Johannes Jensen
    I have a class called Level, which is a subclass of NSObject. Then I have a class called Level_1_1 which is a subclass of Level. Is it allowed to type like Level* aLevel = [Level_1_1 alloc]; instead of Level_1_1* theLevel = [Level_1_1 alloc]; ? :) I try it and I don't get any warnings, just wondering if it's okay to do?

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  • Examples of ISO C++ code that is not valid C++/CLI

    - by Johannes Schaub - litb
    I've seen contradictory answers on the internet with regard to whether C++/CLI is a superset of C++ or not. The accepted answer on this question claims that "technically no", but doesn't provide an examples of non-C++/CLI code that conforms to ISO C++. Another answer on that question cites a book that says the opposite. So, can you please provide accurate answers with example code that fails on C++/CLI or cite a trusted source (MSDN for example) on this matter? I had someone this topic come up today and thought I would like to inform myself, but I didn't find any clear answer elsewhere!

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