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  • Security risks posed by specifying technologies used

    - by SabreWolfy
    I am developing online tools for non-commercial use, which are hosted on dedicated hardware. I would like to include logos indicating the technologies I used (Apache or Python for example), at the bottom of the page. What are the security risks/implications, if any, of "advertizing" this information? It is better not to reveal that the web server is Apache, and that I used Pyhton and jQuery, for example?

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  • Parabolic throw with set Height and range (libgdx)

    - by Tauboga
    Currently i'm working on a minigame for android where you have a rotating ball in the center of the display which jumps when touched in the direction of his current angle. I'm simply using a gravity vector and a velocity vector in this way: positionBall = positionBall.add(velocity); velocity = velocity.add(gravity); and velocity.x = (float) Math.cos(angle) * 12; /* 12 to amplify the velocity */ velocity.y = (float) Math.sin(angle) * 15; /* 15 to amplify the velocity */ That works fine. Here comes the problem: I want to make the jump look the same on all possible resolutions. The velocity needs to be scaled in a way that when the ball is thrown straight upwards it will touch the upper display border. When thrown directly left or right the range shall be exactly long enough to touch the left/right display border. Which formula(s) do I need to use and how to implement them correctly? Thanks in advance!

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  • (Libgdx) Move Vector2 along angle?

    - by gemurdock
    I have seen several answers on here about moving along angle, but I can't seem to get this to work properly for me and I am new to LibGDX... just trying to learn. These are my Vector2's that I am using for this function. public Vector2 position = new Vector2(); public Vector2 velocity = new Vector2(); public Vector2 movement = new Vector2(); public Vector2 direction = new Vector2(); Here is the function that I use to move the position vector along an angle. setLocation() just sets the new location of the image. public void move(float delta, float degrees) { position.set(image.getX() + image.getWidth() / 2, image.getY() + image.getHeight() / 2); direction.set((float) Math.cos(degrees), (float) Math.sin(degrees)).nor(); velocity.set(direction).scl(speed); movement.set(velocity).scl(delta); position.add(movement); setLocation(position.x, position.y); // Sets location of image } I get a lot of different angles with this, just not the correct angles. How should I change this function to move a Vector2 along an angle using the Vector2 class from com.badlogic.gdx.math.Vector2 within the LibGDX library? I found this answer, but not sure how to implement it. Update: I figured out part of the issue. Should convert degrees to radians. However, the angle of 0 degrees is towards the right. Is there any way to fix this? As I shouldn't have to add 90 to degrees in order to have correct heading. New code is below public void move(float delta, float degrees) { degrees += 90; // Set degrees to correct heading, shouldn't have to do this position.set(image.getX() + image.getWidth() / 2, image.getY() + image.getHeight() / 2); direction.set(MathUtils.cos(degrees * MathUtils.degreesToRadians), MathUtils.sin(degrees * MathUtils.degreesToRadians)).nor(); velocity.set(direction).scl(speed); movement.set(velocity).scl(delta); position.add(movement); setLocation(position.x, position.y); }

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  • Installing Phusion Passenger 4.0.20 on Ubuntu 13.10

    - by tempestfire2002
    So I'm trying to install Passenger on the newest version of KUbuntu (13.10). I installed Apache2 using the apache2-mpm-worker package using the Muon Package Manager. And these are the commands I ran. rvmsudo gem install passenger rvmsudo passenger-install-apache2-module But I keep getting the following errors: [Fri Oct 18 15:52:13.227790 2013] [core:warn] [pid 13095] AH00111: Config variable ${APACHE_LOCK_DIR} is not defined [Fri Oct 18 15:52:13.227933 2013] [core:warn] [pid 13095] AH00111: Config variable ${APACHE_PID_FILE} is not defined [Fri Oct 18 15:52:13.227969 2013] [core:warn] [pid 13095] AH00111: Config variable ${APACHE_RUN_USER} is not defined [Fri Oct 18 15:52:13.227991 2013] [core:warn] [pid 13095] AH00111: Config variable ${APACHE_RUN_GROUP} is not defined [Fri Oct 18 15:52:13.228026 2013] [core:warn] [pid 13095] AH00111: Config variable ${APACHE_LOG_DIR} is not defined [Fri Oct 18 15:52:13.231737 2013] [core:warn] [pid 13095:tid 3074562624] AH00111: Config variable ${APACHE_RUN_DIR} is not defined [Fri Oct 18 15:52:13.232760 2013] [core:warn] [pid 13095:tid 3074562624] AH00111: Config variable ${APACHE_LOG_DIR} is not defined [Fri Oct 18 15:52:13.233043 2013] [core:warn] [pid 13095:tid 3074562624] AH00111: Config variable ${APACHE_LOG_DIR} is not defined [Fri Oct 18 15:52:13.233078 2013] [core:warn] [pid 13095:tid 3074562624] AH00111: Config variable ${APACHE_LOG_DIR} is not defined AH00526: Syntax error on line 74 of /etc/apache2/apache2.conf: Invalid Mutex directory in argument file:${APACHE_LOCK_DIR} -------------------------------------------- WARNING: Apache doesn't seem to be compiled with the 'prefork', 'worker' or 'event' MPM Phusion Passenger has only been tested on Apache with the 'prefork', the 'worker' and the 'event' MPM. Your Apache installation is compiled with the '' MPM. We recommend you to abort this installer and to recompile Apache with either the 'prefork', the 'worker' or the 'event' MPM. Press Ctrl-C to abort this installer (recommended). Press Enter if you want to continue with installation anyway. The result of my running apache2ctl -V is: Server version: Apache/2.4.6 (Ubuntu) Server built: Aug 9 2013 14:31:04 Server's Module Magic Number: 20120211:23 Server loaded: APR 1.4.8, APR-UTIL 1.5.2 Compiled using: APR 1.4.8, APR-UTIL 1.5.2 Architecture: 32-bit Server MPM: worker threaded: yes (fixed thread count) forked: yes (variable process count) Server compiled with.... -D APR_HAS_SENDFILE -D APR_HAS_MMAP -D APR_HAVE_IPV6 (IPv4-mapped addresses enabled) -D APR_USE_SYSVSEM_SERIALIZE -D APR_USE_PTHREAD_SERIALIZE -D SINGLE_LISTEN_UNSERIALIZED_ACCEPT -D APR_HAS_OTHER_CHILD -D AP_HAVE_RELIABLE_PIPED_LOGS -D DYNAMIC_MODULE_LIMIT=256 -D HTTPD_ROOT="/etc/apache2" -D SUEXEC_BIN="/usr/lib/apache2/suexec" -D DEFAULT_PIDLOG="/var/run/apache2.pid" -D DEFAULT_SCOREBOARD="logs/apache_runtime_status" -D DEFAULT_ERRORLOG="logs/error_log" -D AP_TYPES_CONFIG_FILE="mime.types" -D SERVER_CONFIG_FILE="apache2.conf" As can be seen, the server is compiled with the worker MPM, so why is passenger complaining? And how do I solve the above errors (warnings, really, but to be safe, I'd like to not have any warnings)? Thanks.

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  • Compute directional light frustum from view furstum points and light direction

    - by Fabian
    I'm working on a friends engine project and my task is to construct a new frustum from the light direction that overlaps the view frustum and possible shadow casters. The project already has a function that creates a frustum for this but its way to big and includes way to many casters (shadows) which can't be seen in the view frustum. Now the only parameter of this function are the normalized light direction vector and a view class which lets me extract the 8 view frustum points in world space. I don't have any additional infos about the scene. I have read some of the related Questions here but non seem to fit very well to my problem as they often just point to cascaded shadow maps. Sadly i can't use DX or openGl functions directly because this engine has a dedicated math library. From what i've read so far the steps are: Transform view frustum points into light space and find min/max x and y values (or sometimes minima and maxima of all three axis) and create a AABB using the min/max vectors. But what comes after this step? How do i transform this new AABB back to world space? What i've done so far: CVector3 Points[8], MinLight = CVector3(FLT_MAX), MaxLight = CVector3(FLT_MAX); for(int i = 0; i<8;++i){ Points[i] = Points[i] * WorldToShadowMapMatrix; MinLight = Math::Min(Points[i],MinLight); MaxLight = Math::Max(Points[i],MaxLight); } AABox box(MinLight,MaxLight); I don't think this is the right way to do it. The near plain probably has to extend into the direction of the light source to include potentional shadow casters. I've read the Microsoft article about cascaded shadow maps http://msdn.microsoft.com/en-us/library/windows/desktop/ee416307%28v=vs.85%29.aspx which also includes some sample code. But they seem to use the scenes AABB to determine the near and far plane which I can't since i cant access this information from the funtion I'm working in. Could you guys please link some example code which shows the calculation of such frustum? Thanks in advance! Additional questio: is there a way to construct a WorldToFrustum matrix that represents the above transformation?

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  • Should I be an algorithm developer, or java web frameworks type developer?

    - by Derek
    So - as I see it, there are really two kinds of developers. Those that do frameworks, web services, pretty-making front ends, etc etc. Then there are developers that write the algorithms that solve the problem. That is, unless the problem is "display this raw data in some meaningful way." In that case, the framework/web developer guy might be doing both jobs. So my basic problem is this. I have been an algorithms kind of software developer for a few years now. I double majored in Math and Computer science, and I have a master's in systems engineering. I have never done any web-dev work, with the exception of a couple minor jobs, and some hobby level stuff. I have been job interviewing lately, and this is what happens: Job is listed as "programmer- 5 years of experience with the following: C/C++, Java,Perl, Ruby, ant, blah blah blah" Recruiter calls me, says they want me to come in for interview In the interview, find out they have some webservices development, blah blah blah When asked in the interview, talk about my experience doing algorithms, optimization, blah blah..but very willing to learn new languages, frameworks, etc Get a call back saying "we didn't think you were a fit for the job you interviewed wtih, but our algorithm team got wind of you and wants to bring you on" This has happened to me a couple times now - see a vague-ish job description looking for a "programmer" Go in, find out they are doing some sort of web-based tool, maybe with some hardcore algorithms running in the background. interview with people for the web-based tool, but get an offer from the algorithms people. So the question is - which job is the better job? I basically just want to get a wide berth of experience at this level of my career, but are algorithm developers so much in demand? Even more so than all these supposed hot in demand web developer guys? Will I be ok in the long run if I go into the niche of math based algorithm development, and just little to no, or hobby level web-dev experience? I basically just don't want to pigeon hole myself this early. My salary is already starting to get pretty high - and I can see a company later on saying "we really need a web developer, but we'll hire this 50k/year college guy, instead of this 100k/year experience algorithm guy" Cliffs notes: I have been doing algorithm development. I consider myself to be a "good programmer." I would have no problem picking up web technologies and those sorts of frameworks. During job interviews, I keep getting "we think you've got a good skillset - talk to our algorithm team" instead of wanting me to learn new skills on the job to do their web services or whhatever other new technology they are doing. Edit: Whenever I am talking about algorithm development here - I am talking about the code that produces the answer. Typically I think of more math-based algorithms: solving a financial problem, solving a finite element method, image processing, etc

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  • How to configure apache2 to just save certain POST requests without even passing them to application?

    - by Robert Grezan
    I'm running apache in front of glassfish server using BalancerMember. For performance reasons I would like that POST requests on certain endpoint are just saved to a file without passing them to application (and to return correct HTTP return code). How to configure apache to do that? EDIT: In other words, if a POST request is for path "http://example.com/upload" then the content of the post (body) should go into a file.

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  • How to make this game loop deterministic

    - by Lanaru
    I am using the following game loop for my pacman clone: long prevTime = System.currentTimeMillis(); while (running) { long curTime = System.currentTimeMillis(); float frameTime = (curTime - prevTime) / 1000f; prevTime = curTime; while (frameTime > 0.0f) { final float deltaTime = Math.min(frameTime, TIME_STEP); update(deltaTime); frameTime -= deltaTime; } repaint(); } The thing is, I don't always get the same ghost movement every time I run the game (their logic is deterministic), so it must be the game loop. I imagine it's due to the final float deltaTime = Math.min(frameTime, TIME_STEP); line. What's the best way of modifying this to perform the exact same way every time I run it? Also, any further improvements I can make?

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  • Dependency Checker/ Installer With Java/Ant

    - by jsn
    I need some kind of software to easily roll out code on new servers. I use Apache Ant for builds. However, say I want to set-up a new server fast and my Java program depends on GhostScript, if there any software that can automatically check the computer for it (and then maybe the PATH) and add it if is not there? I have already looked at Maven and Apache Ivy, however, I think these are only for .jar files (from what I saw). Thanks for any help.

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  • Trying to implement fling events on an object

    - by Adam Short
    I have a game object, well a bitmap, which I'd like to "fling". I'm struggling to get it to fling ontouchlistener due to it being a bitmap and not sure how to proceed and I'm struggling to find the resources to help. Here's my code so far: https://github.com/addrum/Shapes GameActivity class: package com.main.shapes; import android.app.Activity; import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.os.Bundle; import android.view.GestureDetector; import android.view.MotionEvent; import android.view.SurfaceHolder; import android.view.SurfaceView; import android.view.View.OnTouchListener; import android.view.Window; public class GameActivity extends Activity { private GestureDetector gestureDetector; View view; Bitmap ball; float x, y; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); //Remove title bar this.requestWindowFeature(Window.FEATURE_NO_TITLE); view = new View(this); ball = BitmapFactory.decodeResource(getResources(), R.drawable.ball); gestureDetector = new GestureDetector(this, new GestureListener()); x = 0; y = 0; setContentView(view); ball.setOnTouchListener(new OnTouchListener() { @Override public boolean onTouch(android.view.View v, MotionEvent event) { // TODO Auto-generated method stub return false; } }); } @Override protected void onPause() { super.onPause(); view.pause(); } @Override protected void onResume() { super.onResume(); view.resume(); } public class View extends SurfaceView implements Runnable { Thread thread = null; SurfaceHolder holder; boolean canRun = false; public View(Context context) { super(context); holder = getHolder(); } public void run() { while (canRun) { if (!holder.getSurface().isValid()) { continue; } Canvas c = holder.lockCanvas(); c.drawARGB(255, 255, 255, 255); c.drawBitmap(ball, x - (ball.getWidth() / 2), y - (ball.getHeight() / 2), null); holder.unlockCanvasAndPost(c); } } public void pause() { canRun = false; while (true) { try { thread.join(); } catch (InterruptedException e) { e.printStackTrace(); } break; } thread = null; } public void resume() { canRun = true; thread = new Thread(this); thread.start(); } } } GestureListener class: package com.main.shapes; import android.view.GestureDetector.SimpleOnGestureListener; import android.view.MotionEvent; public class GestureListener extends SimpleOnGestureListener { private static final int SWIPE_MIN_DISTANCE = 120; private static final int SWIPE_THRESHOLD_VELOCITY = 200; @Override public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) { if (e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) { //From Right to Left return true; } else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) { //From Left to Right return true; } if (e1.getY() - e2.getY() > SWIPE_MIN_DISTANCE && Math.abs(velocityY) > SWIPE_THRESHOLD_VELOCITY) { //From Bottom to Top return true; } else if (e2.getY() - e1.getY() > SWIPE_MIN_DISTANCE && Math.abs(velocityY) > SWIPE_THRESHOLD_VELOCITY) { //From Top to Bottom return true; } return false; } @Override public boolean onDown(MotionEvent e) { //always return true since all gestures always begin with onDown and<br> //if this returns false, the framework won't try to pick up onFling for example. return true; } }

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  • Applications: The mathematics of movement, Part 1

    - by TechTwaddle
    Before you continue reading this post, a suggestion; if you haven’t read “Programming Windows Phone 7 Series” by Charles Petzold, go read it. Now. If you find 150+ pages a little too long, at least go through Chapter 5, Principles of Movement, especially the section “A Brief Review of Vectors”. This post is largely inspired from this chapter. At this point I assume you know what vectors are, how they are represented using the pair (x, y), what a unit vector is, and given a vector how you would normalize the vector to get a unit vector. Our task in this post is simple, a marble is drawn at a point on the screen, the user clicks at a random point on the device, say (destX, destY), and our program makes the marble move towards that point and stop when it is reached. The tricky part of this task is the word “towards”, it adds a direction to our problem. Making a marble bounce around the screen is simple, all you have to do is keep incrementing the X and Y co-ordinates by a certain amount and handle the boundary conditions. Here, however, we need to find out exactly how to increment the X and Y values, so that the marble appears to move towards the point where the user clicked. And this is where vectors can be so helpful. The code I’ll show you here is not ideal, we’ll be working with C# on Windows Mobile 6.x, so there is no built-in vector class that I can use, though I could have written one and done all the math inside the class. I think it is trivial to the actual problem that we are trying to solve and can be done pretty easily once you know what’s going on behind the scenes. In other words, this is an excuse for me being lazy. The first approach, uses the function Atan2() to solve the “towards” part of the problem. Atan2() takes a point (x, y) as input, Atan2(y, x), note that y goes first, and then it returns an angle in radians. What angle you ask. Imagine a line from the origin (0, 0), to the point (x, y). The angle which Atan2 returns is the angle the positive X-axis makes with that line, measured clockwise. The figure below makes it clear, wiki has good details about Atan2(), give it a read. The pair (x, y) also denotes a vector. A vector whose magnitude is the length of that line, which is Sqrt(x*x + y*y), and a direction ?, as measured from positive X axis clockwise. If you’ve read that chapter from Charles Petzold’s book, this much should be clear. Now Sine and Cosine of the angle ? are special. Cosine(?) divides x by the vectors length (adjacent by hypotenuse), thus giving us a unit vector along the X direction. And Sine(?) divides y by the vectors length (opposite by hypotenuse), thus giving us a unit vector along the Y direction. Therefore the vector represented by the pair (cos(?), sin(?)), is the unit vector (or normalization) of the vector (x, y). This unit vector has a length of 1 (remember sin2(?) + cos2(?) = 1 ?), and a direction which is the same as vector (x, y). Now if I multiply this unit vector by some amount, then I will always get a point which is a certain distance away from the origin, but, more importantly, the point will always be on that line. For example, if I multiply the unit vector with the length of the line, I get the point (x, y). Thus, all we have to do to move the marble towards our destination point, is to multiply the unit vector by a certain amount each time and draw the marble, and the marble will magically move towards the click point. Now time for some code. The application, uses a timer based frame draw method to draw the marble on the screen. The timer is disabled initially and whenever the user clicks on the screen, the timer is enabled. The callback function for the timer follows the standard Update and Draw cycle. private double totLenToTravelSqrd = 0; private double startPosX = 0, startPosY = 0; private double destX = 0, destY = 0; private void Form1_MouseUp(object sender, MouseEventArgs e) {     destX = e.X;     destY = e.Y;     double x = marble1.x - destX;     double y = marble1.y - destY;     //calculate the total length to be travelled     totLenToTravelSqrd = x * x + y * y;     //store the start position of the marble     startPosX = marble1.x;     startPosY = marble1.y;     timer1.Enabled = true; } private void timer1_Tick(object sender, EventArgs e) {     UpdatePosition();     DrawMarble(); } Form1_MouseUp() method is called when ever the user touches and releases the screen. In this function we save the click point in destX and destY, this is the destination point for the marble and we also enable the timer. We store a few more values which we will use in the UpdatePosition() method to detect when the marble has reached the destination and stop the timer. So we store the start position of the marble and the square of the total length to be travelled. I’ll leave out the term ‘sqrd’ when speaking of lengths from now on. The time out interval of the timer is set to 40ms, thus giving us a frame rate of about ~25fps. In the timer callback, we update the marble position and draw the marble. We know what DrawMarble() does, so here, we’ll only look at how UpdatePosition() is implemented; private void UpdatePosition() {     //the vector (x, y)     double x = destX - marble1.x;     double y = destY - marble1.y;     double incrX=0, incrY=0;     double distanceSqrd=0;     double speed = 6;     //distance between destination and current position, before updating marble position     distanceSqrd = x * x + y * y;     double angle = Math.Atan2(y, x);     //Cos and Sin give us the unit vector, 6 is the value we use to magnify the unit vector along the same direction     incrX = speed * Math.Cos(angle);     incrY = speed * Math.Sin(angle);     marble1.x += incrX;     marble1.y += incrY;     //check for bounds     if ((int)marble1.x < MinX + marbleWidth / 2)     {         marble1.x = MinX + marbleWidth / 2;     }     else if ((int)marble1.x > (MaxX - marbleWidth / 2))     {         marble1.x = MaxX - marbleWidth / 2;     }     if ((int)marble1.y < MinY + marbleHeight / 2)     {         marble1.y = MinY + marbleHeight / 2;     }     else if ((int)marble1.y > (MaxY - marbleHeight / 2))     {         marble1.y = MaxY - marbleHeight / 2;     }     //distance between destination and current point, after updating marble position     x = destX - marble1.x;     y = destY - marble1.y;     double newDistanceSqrd = x * x + y * y;     //length from start point to current marble position     x = startPosX - (marble1.x);     y = startPosY - (marble1.y);     double lenTraveledSqrd = x * x + y * y;     //check for end conditions     if ((int)lenTraveledSqrd >= (int)totLenToTravelSqrd)     {         System.Console.WriteLine("Stopping because destination reached");         timer1.Enabled = false;     }     else if (Math.Abs((int)distanceSqrd - (int)newDistanceSqrd) < 4)     {         System.Console.WriteLine("Stopping because no change in Old and New position");         timer1.Enabled = false;     } } Ok, so in this function, first we subtract the current marble position from the destination point to give us a vector. The first three lines of the function construct this vector (x, y). The vector (x, y) has the same length as the line from (marble1.x, marble1.y) to (destX, destY) and is in the direction pointing from (marble1.x, marble1.y) to (destX, destY). Note that marble1.x and marble1.y denote the center point of the marble. Then we use Atan2() to get the angle which this vector makes with the positive X axis and use Cosine() and Sine() of that angle to get the unit vector along that same direction. We multiply this unit vector with 6, to get the values which the position of the marble should be incremented by. This variable, speed, can be experimented with and determines how fast the marble moves towards the destination. After this, we check for bounds to make sure that the marble stays within the screen limits and finally we check for the end condition and stop the timer. The end condition has two parts to it. The first case is the normal case, where the user clicks well inside the screen. Here, we stop when the total length travelled by the marble is greater than or equal to the total length to be travelled. Simple enough. The second case is when the user clicks on the very corners of the screen. Like I said before, the values marble1.x and marble1.y denote the center point of the marble. When the user clicks on the corner, the marble moves towards the point, and after some time tries to go outside of the screen, this is when the bounds checking comes into play and corrects the marble position so that the marble stays inside the screen. In this case the marble will never travel a distance of totLenToTravelSqrd, because of the correction is its position. So here we detect the end condition when there is not much change in marbles position. I use the value 4 in the second condition above. After experimenting with a few values, 4 seemed to work okay. There is a small thing missing in the code above. In the normal case, case 1, when the update method runs for the last time, marble position over shoots the destination point. This happens because the position is incremented in steps (which are not small enough), so in this case too, we should have corrected the marble position, so that the center point of the marble sits exactly on top of the destination point. I’ll add this later and update the post. This has been a pretty long post already, so I’ll leave you with a video of how this program looks while running. Notice in the video that the marble moves like a bot, without any grace what so ever. And that is because the speed of the marble is fixed at 6. In the next post we will see how to make the marble move a little more elegantly. And also, if Atan2(), Sine() and Cosine() are a little too much to digest, we’ll see how to achieve the same effect without using them, in the next to next post maybe. Ciao!

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  • Rotate an image in a scaled context

    - by nathan
    Here is my working piece of code to rotate an image toward a point (in my case, the mouse cursor). float dx = newx - ploc.x; float dy = newy - ploc.y; float angle = (float) Math.toDegrees(Math.atan2(dy, dx)); Where ploc is the location of the image i'm rotating. And here is the rendering code: g.rotate(loc.x + width / 2, loc.y + height / 2, angle); g.drawImage(frame, loc.x, loc.y); Where loc is the location of the image and "width" and "height" are respectively the width and height of the image. What changes are needed to make it works on a scaled context? e.g make it works with something like g.scale(sx, sy).

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  • Truly Random Numbers

    German researchers use a "flip-flop" to improve random number generator Random number generation - Algorithms - Pseudorandom Numbers - Math - Recreation

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  • Subversion/Hudson/Sonar/Artifactory - too much for my little server to handle! Help!

    - by Ricket
    I have a little dedicated server. It's at a cheap price and has a simple AMD 1800+ (1.5ghz), 256mb DDR RAM, ...need I continue? And I think I'm overloading it already. I have installed the following, and it's running CentOS 5.4: Webmin Apache MySQL Subversion as an Apache module Hudson (standalone) Sonar (standalone, runs with a standalone Jetty install) Artifactory (standalone) That's pretty much it. But I'm having problems; pages are loading quite slowly. Network speed of the server is excellent, but I think I'm just running out of CPU and/or memory. A side-effect of the pages loading slowly is that sometimes Hudson times out, not being able to start Maven or contact Sonar in a certain amount of time. I think the next step to speed things up might be to move to an application server and use the WAR version of Hudson, Sonar and Artifactory together on that server. I don't know that it will help, but it just seems to make sense, especially with Sonar running on its own Jetty install and the other two probably running their own mini application servers as well. Am I correct in thinking this? Is this the right course of action? Any other tips on how to make the server run faster? I can post more data if you'd like, just let me know what else would help you answer my question. Oh, also just to cure any suspicions, I don't have any sort of virus or spyware. I protect my SSH access with DenyHosts (which has blocked 300+ brute forcers in the past few months), and I have confirmed that the top four processes in terms of memory and CPU usage are Sonar, Artifactory, Hudson, and MySQL. Edit: I just thought of another thing that I'd like you to comment on as well: Apache currently has 8 spawned slave processes, taking 42MB of ram apiece. This is not my web server. Is everything else able to function if I shut down Apache? Can you point me towards a tutorial or something on migrating Subversion from Apache into something that might work along with the other three applications, maybe even make Subversion a WAR file or something?

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  • When the obvious answer is obviously wrong

    - by John Paul Cook
    This post is about how simple math in T-SQL can produce undesirable results, but first we begin with a math quiz. Answer the following as quickly as possible: You just read pages 100-300 of a book. How many pages did you read? QUICKLY NOW! For those of you who answered 200 pages, I have a new question: Which page did you not read? There were 201 pages to read. If you read 200 pages, you skipped a page! What your answer be if I asked you how many pages did you read if you read pages 1-3? Three pages!...(read more)

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  • What are the fundamentals of game development?

    - by Matt
    Hi, I completely do not understand how a video game can be coded. I'm a beginner programmer and only have experience writing console applications that do math and what not. I do not understand how these logical processes can make images move on the screen (video games). Obviously if i jumped into a game development book or something like that I would understand but I am currently still getting a grasp of the fundamentals of programming in general. Could anyone give a simple explanation , coding wise, on the jump between making a computer do simple math to making a computer produce amazing graphical programs such as video games? Maybe there are some intro videos someone can point me to? I

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  • Keeping rotation between two objects

    - by user99
    In my XNA game I have two objects that collide. When the first object collides with the other it is able to latch on to it and move it about the world. I am having a problem with the math here (Math isn't my strong point). I currently have the second object latch on to the first and move around with it, but I cannot get it to keep it's original direction. So, if the object is facing up it should keep this direction relative to how it is being rotated with the original item. Any tips on how I could best to achieve this?

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  • rsync -c -i flags identical files as different

    - by Scott
    My goal: given a list of files on local server, show any differences to the files with the same absolute path on remote server; e.g. compare local /etc/init.d/apache to same file on remote server. "Difference" for me means different checksum. I don't care about file modification times. I also do not want to sync the files (yet); only show the diffs. I have rsync 3.0.6 on both local and remote servers, which should be able to do what I want. However, it is claiming that local and remote files, even with identical checksums, are still different. Here's the command line: $ rsync --dry-run -avi --checksum --files-from=/home/me/test.txt --rsync-path="cd / && rsync" / me@remote:/ where: "me" = my username; "remote" = remote server hostname current working directory is '/' test.txt contains one line reading "/etc/init.d/apache" OS: Linux 2.6.9 Running cksum on /etc/init.d/apache on both servers yields the same result. The files are the same. However, rsync output is: me@remote's password: building file list ... done .d..t...... etc/ cd+++++++++ etc/init.d/ <f+++++++++ etc/init.d/apache sent 93 bytes received 21 bytes 20.73 bytes/sec total size is 2374 speedup is 20.82 (DRY RUN) The output codes (see http://www.samba.org/ftp/rsync/rsync.html) mean that rsync thinks /etc is identical except for mod time /etc/init.d needs to be changed /etc/init.d/apache will be sent to the remote server I don't understand how, with --checksum option, and the files having identical checksums, that rsync should think they're different. (I've tried with other files having identical mod times, and those files are not flagged as different.) I did run this in /, and made sure (AFAIK) that it's run remotely in /, so even relative pathnames will still be correct. I ran rsync with -avvvi for more debug info, but saw nothing remarkable. I'm wondering: is rsync still looking at file mod times, even with --checksum? am I somehow not setting up the path(s) right? what am I doing wrong?

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  • Deterministic Multiplayer RTS game questions?

    - by Martin K
    I am working on a cross-platform multiplayer RTS game where the different clients and a server(flash and C#), all need to stay deterministically synchronised. To deal with Floatpoint inconsistencies, I've come across this method: http://joshblog.net/2007/01/30/flash-floating-point-number-errors/#comment-49912 which basically truncates off the nondeterministic part: return Math.round(1000 * float) / 1000; Howewer my concern is that every time there is a division, there is further chance of creating additional floatpoint errors, in essence making it worse? . So it occured to me, how about something like this: function floatSafe(number:Number) : Number {return Math.round(float* 1024) / 1024; } ie dividing with only powers of 2 ? What do you think? . Ironically with the above method I got less accurate results: trace( floatSafe(3/5) ) // 0.599609375 where as with the other method(dividing with 1000), or just tracing the raw value I am getting 3/5 = 0.6 or Maybe thats what 3/5 actually is, IE 0.6 cannot really be represented with a floatpoint datatype, and would be more consistent across different platforms?

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  • HedgeWar code confusion

    - by BluFire
    I looked at an open source project(HedgeWars) that was built using many programming languages such as C++ and Java. While I was looking through the code, I couldn't help noticing that all the math and physics were gone from the Java code. HedgeWars I imported the project file called "SDL-android-project" which was a sub folder to "android build" and project files. My question is where is all the math and physics inside the code? Do I have to look at the C++ code in order to see it? I think Hedgewars was originally programmed in C++ but the files are confusing be because of its size and the fact that it has several programming languages inside.

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  • nginx can't see MySQL

    - by user135235
    I have a fully working Joomla 2.5.6 install driven by a local MySQL server, but I'd like to test nginx to see if it's a faster web serving experience than Apache. \ PHP 5.4.6 (PHP54w) \ CentOS 6.2 \ Joomla 2.5.6 \ PHP54w-fpm.i386 (FastCGI process manager) \ php -m shows: mysql & mysqli modules loaded Nginx seems to have installed fine via yum, it can process a PHP-info file via FastCGI perfectly OK (http://37.128.190.241/php.php) but when I stop Apache, start nginx instead and visit my site I get: "Database connection error (1): The MySQL adapter 'mysqli' is not available." I've tried adjusting my Joomla configuration.php to use mysql instead of mysqli but I get the same basic error, only this time "Database connection error (1): The MySQL adapter 'mysql' is not available" of course! Can anyone think what the problem might be please? I did try explicitly setting extension = mysqli.so and extension = mysql.so in my php.ini to try and force the issue (despite php -m showing they were both successfully loaded anyway) - no difference. I have a pretty standard nginx default.conf: server { listen 80; server_name www.MYDOMAIN.com; server_name_in_redirect off; access_log /var/log/nginx/localhost.access_log main; error_log /var/log/nginx/localhost.error_log info; root /var/www/html/MYROOT_DIR; index index.php index.html index.htm default.html default.htm; # Support Clean (aka Search Engine Friendly) URLs location / { try_files $uri $uri/ /index.php?q=$uri&$args; } # deny running scripts inside writable directories location ~* /(images|cache|media|logs|tmp)/.*\.(php|pl|py|jsp|asp|sh|cgi)$ { return 403; error_page 403 /403_error.html; } location ~ \.php$ { fastcgi_pass 127.0.0.1:9000; fastcgi_index index.php; include fastcgi_params; fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name; include /etc/nginx/fastcgi.conf; } # caching of files location ~* \.(ico|pdf|flv)$ { expires 1y; } location ~* \.(js|css|png|jpg|jpeg|gif|swf|xml|txt)$ { expires 14d; } } Snip of output from phpinfo under nginx: Server API FPM/FastCGI Virtual Directory Support disabled Configuration File (php.ini) Path /etc Loaded Configuration File /etc/php.ini Scan this dir for additional .ini files /etc/php.d Additional .ini files parsed /etc/php.d/curl.ini, /etc/php.d/fileinfo.ini, /etc/php.d/json.ini, /etc/php.d/phar.ini, /etc/php.d/zip.ini Snip of output from phpinfo under Apache: Server API Apache 2.0 Handler Virtual Directory Support disabled Configuration File (php.ini) Path /etc Loaded Configuration File /etc/php.ini Scan this dir for additional .ini files /etc/php.d Additional .ini files parsed /etc/php.d/curl.ini, /etc/php.d/fileinfo.ini, /etc/php.d/json.ini, /etc/php.d/mysql.ini, /etc/php.d/mysqli.ini, /etc/php.d/pdo.ini, /etc/php.d/pdo_mysql.ini, /etc/php.d/pdo_sqlite.ini, /etc/php.d/phar.ini, /etc/php.d/sqlite3.ini, /etc/php.d/zip.ini Seems that with Apache, PHP is loading substantially more additional .ini files, including ones relating to mysql (mysql.ini, mysqli.ini, pdo_mysql.ini) than nginx. Any ideas how I get nginix to also call these additional .ini's ? Thanks in advance, Steve

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  • What kind of spam is this?

    - by SSilk
    I realize this is a pretty vague question, but I occasionally get spam messages through my contact form on a Drupal 6 site. The contact form does not have any anti-spam protection (i.e. math question). The messages I get are all very similar and just jumbled junk, like below, so I think they're all from the same source. Example: ylsaf0V bpsdfuxnhjjd, [url=http://wwgfsggzgyjyjm.com/]wwgrfgzrgsjyjm[/url], [link=http://xmgvyghcuufvb.com/]xmjyhvyjyfjirovb[/link], http://frgxmdghrgruhfc.com/ Anyway, I'm just wondering what the point of such a message is. All the links are dead, it's illegible, and it's not trying to sell me a product or get me to do anything, so I'm a bit perplexed. Is there any way to tell where they're coming from? And how concerned should I be? To be clear, I'm not asking how to avoid them, I realize just adding a simple math challenge or captcha would likely do the job.

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  • Passive Income for a programmer : Teaching

    - by Victor
    While looking into passive income streams for someone with a Science/math/Engineering/Programming background, I ran into various ideas. I was looking to generate a passive income that would not take too much of an initiall learning curve. And it occurs to me that teaching/writing books/ on High School math/Physics/English is something I can do without a lot of prepwork. I am in Toronto . what are the average income opportunities for something like this? Where should I start looking?

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