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  • How to JSON serialize math vector type in F#?

    - by The_Ghost
    Hello! I'm trying to serialize "vector" (Microsoft.FSharp.Math) type. And I get that error: Exception Details: System.Runtime.Serialization.SerializationException: Type 'Microsoft.FSharp.Math.Instances+FloatNumerics@115' with data contract name 'Instances.FloatNumerics_x0040_115:http://schemas.datacontract.org/2004/07/Microsoft.FSharp.Math' is not expected. Add any types not known statically to the list of known types - for example, by using the KnownTypeAttribute attribute or by adding them to the list of known types passed to DataContractSerializer. I have tried to put KnownType attribute and some other stuff, but nothing helps! Could someone know the answer? This is the code I use: // [< KnownType( typeof<vector> ) >] type MyType = vector let public writeTest = let aaa = vector [1.1;2.2] let serializer = new DataContractJsonSerializer( typeof<MyType> ) let writer = new StreamWriter( @"c:\test.txt" ) serializer.WriteObject(writer.BaseStream, aaa) writer.Close()

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  • snapping an angle to the closest cardinal direction

    - by Josh E
    I'm developing a 2D sprite-based game, and I'm finding that I'm having trouble with making the sprites rotate correctly. In a nutshell, I've got spritesheets for each of 5 directions (the other 3 come from just flipping the sprite horizontally), and I need to clamp the velocity/rotation of the sprite to one of those directions. My sprite class has a pre-computed list of radians corresponding to the cardinal directions like this: protected readonly List<float> CardinalDirections = new List<float> { MathHelper.PiOver4, MathHelper.PiOver2, MathHelper.PiOver2 + MathHelper.PiOver4, MathHelper.Pi, -MathHelper.PiOver4, -MathHelper.PiOver2, -MathHelper.PiOver2 + -MathHelper.PiOver4, -MathHelper.Pi, }; Here's the positional update code: if (velocity == Vector2.Zero) return; var rot = ((float)Math.Atan2(velocity.Y, velocity.X)); TurretRotation = SnapPositionToGrid(rot); var snappedX = (float)Math.Cos(TurretRotation); var snappedY = (float)Math.Sin(TurretRotation); var rotVector = new Vector2(snappedX, snappedY); velocity *= rotVector; //...snip private float SnapPositionToGrid(float rotationToSnap) { if (rotationToSnap == 0) return 0.0f; var targetRotation = CardinalDirections.First(x => (x - rotationToSnap >= -0.01 && x - rotationToSnap <= 0.01)); return (float)Math.Round(targetRotation, 3); } What am I doing wrong here? I know that the SnapPositionToGrid method is far from what it needs to be - the .First(..) call is on purpose so that it throws on no match, but I have no idea how I would go about accomplishing this, and unfortunately, Google hasn't helped too much either. Am I thinking about this the wrong way, or is the answer staring at me in the face?

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  • Polygon is rotating too fast

    - by Manderin87
    I am going to be using a polygon collision detection method to test when objects collide. I am attempting to rotate a polygon to match the sprites rotation. However, the polygon is rotating too fast, much faster than the sprite is. I feel its a timing issue, but the sprite rotates like it is supposed to. Can anyone look at my code and tell me what could be causing this issue? public void rotate(float x0, float y0, double angle) { for(Point point : mPoints) { float x = (float) (x0 + (point.x - x0) * Math.cos(Utilities.toRadians(angle)) - (point.y - y0) * Math.sin(Utilities.toRadians(angle))); float y = (float) (y0 + (point.x - x0) * Math.sin(Utilities.toRadians(angle)) + (point.y - y0) * Math.cos(Utilities.toRadians(angle))); point.x = x; point.y = y; } } This algorithm works when done singly, but once I plug it into the update method the rotation is too fast. The Points used are: P1 608, 368 P2 640, 464 P3 672, 400 Origin x0 is: 640 400 The angle goes from 0 to 360 as the sprite rotates. When the codes executes the triangle looks like a star because its moving so fast. The rotation is done in the sprites update method. The rotation method just increases the sprites degree by .5 when it executes. public void update() { if(isActive()) { rotate(); mBounding.rotate(mPosition.x, mPosition.y, mDegree); } }

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  • Making user input/math on data fast, unlike excel type programs

    - by proGrammar
    I'm creating a research platform solely for myself to do some research on data. Programs like excel are terribly slow for me so I'm trying to come up with another solution. Originally I used excel. A1 was the cell that contained the data and all other cells in use calculated something on A1, or on other cells, that all could be in the end traced to A1. A1 was like an element of an array, I then I incremented it to go through all my data. This was way too slow. So the only other option I found originally was to hand code in c# the calculations inside a loop. Then I simply recompiled each time I changed my math. This was terribly slow to do and I had to order everything correctly so things would update correctly (dependencies). I could have also used events, but hand coding events for each cell like calculation would also be very slow. Next I created an application to read Excel and to perfectly imitate it. Which is what I now use. Basically I write formulas onto a fraction of my data to get live results inside excel. Then my program reads excel, writes another c# program, compiles it, and runs that program which runs my excel created formulas through a lot more data a whole lot faster. The advantage being my application dependency sorts everything (or I could use events) so I don't have to (like excel does) And of course the speed. But now its not a single application anymore. Instead its 2 applications, one which only reads my formulas and writes another program. The other one being the result which only lives for a short while before I do other runs through my data with different formulas / settings. So I can't see multiple results at one time without introducing even more programs like a database or at least having the 2 applications talking to each other. My idea was to have a dll that would be written, compiled, loaded, and unloaded again and again. So a self-updating program, sort of. But apparently that's not possible without another appdomain which means data has to be marshaled to be moved between the appdomains. Which would slow things down, not for summaries, but for other stuff I need to do with all my data. I'm also forgetting to mention a huge problem with restarting an application again and again which is having to reload ALL my data into memory again and again. But its still a whole lot faster than excel. I'm really super puzzled as to what people do when they want to research data fast. I'm completely unable to have a program accept user input and having it fast. My understanding is that it would have to do things like excel which is to evaluate strings again and again. So my only option is to repeatedly compile applications. Do I have a correct understanding on computer science? I've only just began programming, and didn't think I would have to learn much to do some simple math on data. My understanding is its either compiling my user defined stuff to a program or evaluating them from a string or something stupid again and again. And my only option is to probably switch operating systems or something to be able to have a program compile and run itself without stopping (writing/compiling dll, loading dll to program, unloading, and repeating). Can someone give me some idea on how computers work? Is anything better possible? Like a running program, that can accept user input and compile it and then unload it later? I mean heck operating systems dont need to be RESTARTED with every change to user input. What is this the cave man days? Sorry, it's just so super frustrating not knowing what one can do, and can't do. If only I could understand and learn this stuff fast enough.

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  • Properly force SSL with .htaccess, no double authentication

    - by cwd
    I'm trying to force SSL with .htaccess on a shared host. This means there I only have access to .htaccess and not the vhosts config. I know you can put a rule in the VirtualHost config file to force SSL which will be picked up there (and acted upon first), preventing double authentication, but I can't get to that. Here's the progress I've made: Config 1 This works pretty well but it does force double authentication if you visit http://site.com - once for http and then once for https. Once you are logged in, it automatically redirects http://site.com/page1.html to the https coutnerpart just fine: RewriteEngine On RewriteCond %{HTTPS} !=on RewriteRule ^ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301] RewriteEngine on RewriteCond %{HTTP_HOST} !(^www\.site\.com*)$ RewriteRule (.*) https://www.site.com$1 [R=301,L] AuthName "Locked" AuthUserFile "/home/.htpasswd" AuthType Basic require valid-user Config 2 If I add this to the top of the file, it works a lot better in that it will switch to SSL before prompting for the password: SSLOptions +StrictRequire SSLRequireSSL SSLRequire %{HTTP_HOST} eq "site.com" ErrorDocument 403 https://site.com It's clever how it will use the SSLRequireSSL option and the ErrorDocument403 to redirect to the secure version of the site. My only complaint is that if you try and access http://site.com/page1.html it will redirect to https://site.com/ So it is forcing SSL without a double-login, but it is not properly forwarding non-SSL resources to their SSL counterparts. Regarding the first config, Insyte mentioned "using mod_rewrite to perform a simple redirect is a bit of overkill. Use the Redirect directive instead. It's possible this may even fix your problem, as I believe mod_rewrite rules are some of the last directives to be processed, just before the file is actually grabbed from the filesystem" I have not had no such luck on finding a force-ssl config option with the redirect directive and so have been unable to test this theory.

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  • Double audio cd ripping weirdness

    - by jqno
    Since I installed Ubuntu 12.04, Rhythmbox, Banshee and Sound Juicer have started acting weird around double cd's, and specifically, cd #2 of said double cd. Sometimes, they will show the information of cd #1. Track names, durations, and even count are incorrect. Sometimes, they will first show the tracks for cd #1, then continue onto cd #2 if cd #2 has more tracks than #1. Sound Juicer seems to be unable to find any track durations at all, even for single cd's. Obviously, this is a pain when I'm trying to rip double cd's. And I have a fair number of them, which I want to rip. This happens on both my machines (a slightly aging iMac, and a 1-year-old Sony Vaio). However, on previous versions of Ubuntu, this never happened. All on the same machines. So I suspect 12.04 is using a different lib for extracting audio cd data. Just for kicks, I tried with Linux Mint 13, and there it works correctly, even though it claims to be based on Ubuntu 12.04 and therefore should be using (partially) the same software. So if the Mint guys can fix it, I should be able to do it too, right? So, my question: what changed in 12.04 that could cause this? And more importantly: what can I do to fix it?

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  • Isometric - precise screen coordinates to isometric

    - by Rawrz
    I'm trying to translate mouse coords to precise isometric coords (I can already find the tile the mouse is over, but I want it to be more precise). I've tried several different methods but I seem to keep falling short. For drawing I use: batch.draw( texture, (y * tileWidth / 2) + (x * tileWidth / 2), (x * tileHeight / 2) - (y * tileHeight / 2)) This is what I currently use for figuring out a tile position: float xt = x + camPosition.x - (ScreenWidth/2) ; float yt = (ScreenHeight) - y + camPosition.y - (ScreenHeight/2); int tileY = Math.round((((xt) / tileWidth) - ((yt) / tileHeight))); int tileX = Math.round((((xt) / tileWidth) + ((yt) / tileHeight))- 1); I'm just wondering how I could update these to allow for more precise coordinates, instead of tile only. EDIT: Following what ccxvii said below, and removing the -1 from tileX, the object follows my mouse just like I had wanted. Just going to re-examine the math and figure out if that change will result in other messes =o

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  • Third-Grade Math Class

    - by andyleonard
    An Odd Thing Happened... ... when I was in third grade math class: I was handed a sheet of arithmetic problems to solve. There were maybe 20 problems on the page and we were given the remainder of the class to complete them. I don't remember how much time remained in the class, I remember I finished working on the problems before my classmates. That wasn't the odd part. The odd part was that I started working on the first problem, concentrating pretty hard. I worked the sum and moved to the next...(read more)

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  • How does a website like Mathway work?

    - by Bob
    I recently found a website called Mathway Basically, it works by allowing you to choose your "level of math" (which it uses to determine what tools it should provide to you) and then allows you to input a math problem which it then solves for you, and gives you detailed solutions (you have to try it, it's really cool). I was wondering how it worked on two levels. First off, how would they parse the math problem (and all the sometimes foreign mathematical operators)? How do they get from text to numbers, variables, and operators? Second, how do they generate the explanations? While you have to pay for the detailed solutions (which are explanations of how they solved the problem), I've seen their preview screenshots, and it looks very detailed. The explanations are given in full, accurate sentences. How would they generate something like that?

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  • Rotate a vector by given degrees (errors when value over 90)

    - by Ivan
    I created a function to rotate a vector by a given number of degrees. It seems to work fine when given values in the range -90 to +90. Beyond this, the amount of rotation decreases, i.e., I think objects are rotating the same amount for 80 and 100 degrees. I think this diagram might be a clue to my problem, but I don't quite understand what it's showing. Must I use a different trig function depending on the radians value? The programming examples I've been able to find look similar to mine (not varying the trig functions). Vector2D.prototype.rotate = function(angleDegrees) { var radians = angleDegrees * (Math.PI / 180); var ca = Math.cos(radians); var sa = Math.sin(radians); var rx = this.x*ca - this.y*sa; var ry = this.x*sa + this.y*ca; this.x = rx; this.y = ry; };

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  • Math behind multivariate testing for website optimization

    - by corkjack
    I am looking for theoretical resources (books, tutorials, etc.) to learn about making sound statistical inferences given (plenty of) multivariate website conversion data. I'm after the math involved, and cannot find any good non-marketing stuff on the web. The sort of questions I want to answer: how much impact does a single variable (e.g. color of text) have? what is the correlation between variables? what type of distribution is used for modelling (Gaussian, Binomial, etc.)? When using statistics to analyze results - what should be considered as a random variable - the web-page element that gets different variations or the binary conversion-or-no-conversion outcome of an impression? There's plenty of information about different website optimization testing methods and their benefits\pitfalls, plenty of information about multivariate statistics in general, do you guys know of resources that discuss statistics in this specific context of website optimization ? Thanks for any info!

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  • return an address of a double

    - by bks
    i'm having an issue understanding why the following works: void doubleAddr(double* source, double** dest) { *dest = source; } i get a pointer to a double and want to change the double that dest points to: //usage: int main() { double* num; double* dest; doubleAddr(num, &dest); return 0; } thanks in advance

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  • Double Click to open Office docs is slow, File -> Open is fast.

    - by Keith
    I have 2 unique networks. They both share similar architecture: Windows 2003 SBS SP2 Running Symantec Endpoint Running Symantec Information Foundation Shared drives off a data partition Clients running Office 2003 or 2007 Connect to file server through mapped drives When users try to open a file from their local PC by double clicking, it will take 30-60 seconds to open. When they do File - Open, those same documents open up almost immediately. So far I've tried the following - CCleaner to parse the registry of outdated mapped drives - Disabled "using DDE" - Disabled A/V - Reboot Any ideas beyond that? Figured this question belongs here instead of SU since its the same issue on different networks.

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  • Problem in List<double[,]>

    - by Newbie
    What is wrong with this (in C# 3.0): List<double> x = new List<double> { 0.0330, -0.6463, 0.1226, -0.3304, 0.4764, -0.4159, 0.4209, -0.4070, -0.2090, -0.2718, -0.2240, -0.1275, -0.0810, 0.0349, -0.5067, 0.0094, -0.4404, -0.1212 }; List<double> y = new List<double> { 0.4807, -3.7070, -4.5582, -11.2126, -0.7733, 3.7269, 2.7672, 8.3333, 4.7023,0,0,0,0,0,0,0,0,0 }; List<double[,]> z = new List<double[,]>{x,y}; // this line The error produced is: Error: Argument '1': cannot convert from 'System.Collections.Generic.List<double>' to 'double[*,*]' Help needed.

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  • Convert list to double[][] in C#3.0

    - by Newbie
    Given List<double> x1 = new List<double> { -0.2718, -0.2240, -0.1275, -0.0810, 0.0349, -0.5067, 0.0094, -0.4404, -0.1212 }; List<double> x2 = new List<double> { 0.0330, -0.6463, 0.1226, -0.3304, 0.4764, -0.4159, 0.4209, -0.4070, -0.2090 }; How can I make as double[][] X at runtime(programatically). I mean to say if the output I get if I run double[][] X = { new double[] { -0.2718, -0.2240, -0.1275, -0.0810, 0.0349, -0.5067, 0.0094, -0.4404, -0.1212 }, new double[] { 0.0330, -0.6463, 0.1226, -0.3304, 0.4764, -0.4159, 0.4209, -0.4070, -0.2090 } }; Using C#3.0 Thanks

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  • The perils of double-dash comments [T-SQL]

    - by jamiet
    I was checking my Twitter feed on my way in to work this morning and was alerted to an interesting blog post by Valentino Vranken that highlights a problem regarding the OLE DB Source in SSIS. In short, using double-dash comments in SQL statements within the OLE DB Source can cause unexpected results. It really is quite an important read if you’re developing SSIS packages so head over to SSIS OLE DB Source, Parameters And Comments: A Dangerous Mix! and be educated. Note that the problem is solved in SSIS2012 and Valentino explains exactly why. If reading Valentino’s post has switched your brain into “learn mode” perhaps also check out my post SSIS: SELECT *... or select from a dropdown in an OLE DB Source component? which highlights another issue to be aware of when using the OLE DB Source. As I was reading Valentino’s post I was reminded of a slidedeck by Chris Adkin entitled T-SQL Coding Guidelines where he recommends never using double-dash comments: That’s good advice! @Jamiet

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  • Double-click instead of single-click in Ubuntu 12.04

    - by evfwcqcg
    When I do a single click, my computer (with Ubuntu 12.04) acts like it was double click. I think it happens in ~50% of cases. It happens with all the program I use: browsers, file manager, terminal and so on. I'm not sure when exactly it started, maybe a week ago, and I don't remember if it started to happen after system-update or after the installation of some packages. What I tried: change mouse change mouse settings like Double-Click Timeout None of those helped me. Any ideas? Thanks.

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  • Creating a C++ DLL and then using it in C#

    - by Major
    Ok I'm trying to make a C++ DLL that I can then call and reference in a c# App. I've already made a simple dll using the numberous guides out there, however when I try to reference it in the C# app I get the error Unable to load DLL 'SDES.dll': The specified module could not be found. The code for the program is as follows (bear with me I'm going to include all the files) //These are the DLL Files. ifndef TestDLL_H define TestDLL_H extern "C" { // Returns a + b __declspec(dllexport) double Add(double a, double b); // Returns a - b __declspec(dllexport) double Subtract(double a, double b); // Returns a * b __declspec(dllexport) double Multiply(double a, double b); // Returns a / b // Throws DivideByZeroException if b is 0 __declspec(dllexport) double Divide(double a, double b); } endif //.cpp include "test.h" include using namespace std; extern double __cdecl Add(double a, double b) { return a + b; } extern double __cdecl Subtract(double a, double b) { return a - b; } extern double __cdecl Multiply(double a, double b) { return a * b; } extern double __cdecl Divide(double a, double b) { if (b == 0) { throw new invalid_argument("b cannot be zero!"); } return a / b; } //C# Program using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Runtime.InteropServices; namespace ConsoleApplication1 { class Program { [DllImport("SDES.dll")] public static extern void SimulateGameDLL(int a, int b); static void Main(string[] args) { SimulateGameDLL(1, 2); //Error here... } } } Anyone have any idea's what I may be missing in my program? Let me know if I missed some code or if you have any questions.

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  • How can I convert a byte array into a double and back?

    - by user350005
    For converting a byte array to a double I found this: //convert 8 byte array to double int start=0;//??? int i = 0; int len = 8; int cnt = 0; byte[] tmp = new byte[len]; for (i = start; i < (start + len); i++) { tmp[cnt] = arr[i]; //System.out.println(java.lang.Byte.toString(arr[i]) + " " + i); cnt++; } long accum = 0; i = 0; for ( int shiftBy = 0; shiftBy < 64; shiftBy += 8 ) { accum |= ( (long)( tmp[i] & 0xff ) ) << shiftBy; i++; } return Double.longBitsToDouble(accum); But I could not find anything which would convert a double into a byte array.

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  • Apache Jmeter + Random Double

    - by Filipe Batista
    Is it possible to generate random double numbers in JMeter? I tried to use the Random in the config element where i have defined the Minimum value: 47.9999 (RND1) Maximum value: 30.9999 (RND2) Then in the selected Prepared Selected Statement i placed this values: Parameter values:${RND1},${RND1},${RND2} Parameter types:DOUBLE,DOUBLE,DOUBLE But it seems not work, because i receive an error: Response message: java.sql.SQLException: Cannot convert class java.lang.String to SQL type requested due to java.lang.NumberFormatException - For input string: "${RND1}"

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  • How many double numbers are there between 0.0 and 1.0?

    - by polygenelubricants
    This is something that's been on my mind for years, but I never took the time to ask before. Many (pseudo) random number generators generate a random number between 0.0 and 1.0. Mathematically there are infinite numbers in this range, but double is a floating point number, and therefore has a finite precision. So the questions are: Just how many double numbers are there between 0.0 and 1.0? Are there just as many numbers between 1 and 2? Between 100 and 101? Between 10^100 and 10^100+1? Note: if it makes a difference, I'm interested in Java's definition of double in particular.

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