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  • Stack usage with MMX intrinsics and Microsoft C++

    - by arik-funke
    I have an inline assembler loop that cumulatively adds elements from an int32 data array with MMX instructions. In particular, it uses the fact that the MMX registers can accommodate 16 int32s to calculate 16 different cumulative sums in parallel. I would now like to convert this piece of code to MMX intrinsics but I am afraid that I will suffer a performance penalty because one cannot explicitly intruct the compiler to use the 8 MMX registers to accomulate 16 independent sums. Can anybody comment on this and maybe propose a solution on how to convert the piece of code below to use intrinsics? == inline assembler (only part within the loop) == paddd mm0, [esi+edx+8*0] ; add first & second pair of int32 elements paddd mm1, [esi+edx+8*1] ; add third & fourth pair of int32 elements ... paddd mm2, [esi+edx+8*2] paddd mm3, [esi+edx+8*3] paddd mm4, [esi+edx+8*4] paddd mm5, [esi+edx+8*5] paddd mm6, [esi+edx+8*6] paddd mm7, [esi+edx+8*7] ; add 15th & 16th pair of int32 elements esi points to the beginning of the data array edx provides the offset in the data array for the current loop iteration the data array is arranged such that the elements for the 16 independent sums are interleaved.

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  • What is wrong with this recursive Windows CMD script? It won't do Ackermann properly

    - by boost
    I've got this code that I'm trying to get to calculate the Ackermann function so that I can post it up on RosettaCode. It almost works. I thought maybe there'd be a few batch file wizards on StackOverflow. ::echo off set depth=0 :ack if %1==0 goto m0 if %2==0 goto n0 :else set /a n=%2-1 set /a depth+=1 call :ack %1 %n% set t=%errorlevel% set /a depth-=1 set /a m=%1-1 set /a depth+=1 call :ack %m% %t% set t=%errorlevel% set /a depth-=1 if %depth%==0 ( exit %t% ) else ( exit /b %t% ) :m0 set/a n=%2+1 if %depth%==0 ( exit %n% ) else ( exit /b %n% ) :n0 set /a m=%1-1 set /a depth+=1 call :ack %m% %2 set t=%errorlevel% set /a depth-=1 if %depth%==0 ( exit %t% ) else ( exit /b %t% ) I use this script to test it @echo off cmd/c ackermann.cmd %1 %2 echo Ackermann of %1 %2 is %errorlevel% A sample output, for Test 1 1, gives: >test 1 1 >set depth=0 >if 1 == 0 goto m0 >if 1 == 0 goto n0 >set /a n=1-1 >set /a depth+=1 >call :ack 1 0 >if 1 == 0 goto m0 >if 0 == 0 goto n0 >set /a m=1-1 >set /a depth+=1 >call :ack 0 0 >if 0 == 0 goto m0 >set/a n=0+1 >if 2 == 0 (exit 1 ) else (exit /b 1 ) >set t=1 >set /a depth-=1 >if 1 == 0 (exit 1 ) else (exit /b 1 ) >set t=1 >set /a depth-=1 >set /a m=1-1 >set /a depth+=1 >call :ack 0 1 >if 0 == 0 goto m0 >set/a n=1+1 >if 1 == 0 (exit 2 ) else (exit /b 2 ) >set t=2 >set /a depth-=1 >if 0 == 0 (exit 2 ) else (exit /b 2 ) Ackermann of 1 1 is 2

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  • Deep Zoom in Ajax - Possible? Any examples out there?

    - by Phil
    I have an idea to implement a deep zoom type interface hosted in a browser for sports training data (speed, distance, heart rate etc.) However, rather than images I actually want to zoom into a hierarchy of information. For example, the initial display would contain a grid of years - hover over 2008, for example, and spin the mouse wheel (or click) will zoom into that year but during the zoom I want 2008 to fade out and be replaced with a calendar of months. Again zoom into a month and the months are replaced with the months calendar, zoom into a day and you finally see a chart with the training data plotted on it. All the time only dates with actual data would be highlighted in some fashion. My question is whether this would even be possible and whether anyone has seen examples of this already. I'm imagining that most of the time the next level of information could be cached in the browser (in fact, because this is calendar-based, I can calculate most of that and cache the dates to be highlighted.) I could also zoom into an empty chart whilst an Ajax thread is fetching the data to display. I've never tried anything like this before and I'm especially interested in whether DHTML would be capable of this sort of zoom (I suspect not and I would have to resort to Silverlight) and whether the Ajax execution would be uninterrupted whilst the browser rendering thread is kept busy zooming.

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  • Font advance calculation problem on Blackberry OS 5.0

    - by John
    I am currently working on my own implementation of a tab bar for a BlackBerry app, where each tab bar has a title that is right aligned (i.e. the last character in each should be the same distance from the right hand side of the screen). To work out where to draw the text I am using the following calculation: screen width - advance of title - indent. The font I am using is 'BBAlpha Sans' (height 28). Using BlackBerry OS 4.6 everything seems to be calculated properly and the text is aligned when I move between tabs, however I am finding that when I use OS 5.0 it doesn't calculate the advance properly and as a result the alignment is off by maybe 5 pixels or so. With the default font (also BBAlpha Sans, but height 24 - for OS 5.0 at least) it works fine in both versions.. but I don't necessarily always want to use the default font/size, so any ideas what could be going wrong? Is this a bug in the 5.0 API? Thanks. Code: public class TitleBarBackground extends Background { .. public void draw(Graphics graphics, XYRect rect) { graphics.pushRegion(rect); .. Font titleBarFont = FontFamily.forName("BBAlpha Sans").getFont(Font.PLAIN, 28); ... int textWidth = titleBarFont.getAdvance(title); graphics.drawText(title, rect.width - textWidth - TITLE_OFFSET, textYOffset); graphics.popContext(); } .. }

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  • Confused about UIView frame property

    - by slowfungus
    I'm building a prototype iPad app that draws diagrams. I have the following view hierarchy: UIView UIScrollView DiagramView : UIView TabBar NavigationBar And a UIViewController subclass holding all that together. Before drawing the diagram the first time I calculate the dimensions of the diagram, and set the DiagramView frame to that size, and the content size of the scrollview as well. -(void)recalculateBounds { [renderer diagram:diagram shouldDraw:NO]; SQXRect diagramRect = SQXMakeRect(0.0,0.0,[diagram bounds].size.width,[diagram bounds].size.height); self.frame = diagramRect; [(UIScrollView*)[self superview] setContentSize:diagramRect.size]; } I should disclose that the frame is being set to about 1500 x 3500 which i know is ridiculous. I just want to focus on some other parts of the app before I get into optimizing the render code. This works beautifully, except that the rect being passed to drawRect is not the size that I set, and my drawing is getting clipped at the bottom. Its close the size i set, but bigger in width, and shorter in height. Also of note, is the fact that if I force the frame to be much bigger than what I know the diagram needs, then the drawRect:rect is big enough, and no clipping occurs. Of course this has me wondering if the frame size needs to take into account some other screen real estate like the toolbars but my reading of the docs tells me the frame is in superview coordinates, which would be the scrollview so I reckon I need to worry about such things. Any idea what is causing this discrepancy?

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  • Head Rotation in Opposite Direction with GLM and Oculus Rift SDK

    - by user3434662
    I am 90% there in getting orientation to work. I am just trying to resolve one last bit and I hope someone can point me to any easy errors I am making but not seeing. My code works except when a person looks left the camera actually rotates right. Vice versa with looking right, camera rotates left. Any idea what I am doing wrong here? I retrieve the orientation from the Oculus Rift like so: OVR::Quatf OculusRiftOrientation = PredictedPose.Orientation; glm::vec3 CurrentEulerAngles; glm::quat CurrentOrientation; OculusRiftOrientation.GetEulerAngles<OVR::Axis_X, OVR::Axis_Y, OVR::Axis_Z, OVR::Rotate_CW, OVR::Handed_R> (&CurrentEulerAngles.x, &CurrentEulerAngles.y, &CurrentEulerAngles.z); CurrentOrientation = glm::quat(CurrentEulerAngles); And here is how I calculate the LookAt: /* DirectionOfWhereCameraIsFacing is calculated from mouse and standing position so that you are not constantly rotating after you move your head. */ glm::vec3 DirectionOfWhereCameraIsFacing; glm::vec3 RiftDirectionOfWhereCameraIsFacing; glm::vec3 RiftCenterOfWhatIsBeingLookedAt; glm::vec3 PositionOfEyesOfPerson; glm::vec3 CenterOfWhatIsBeingLookedAt; glm::vec3 CameraPositionDelta; RiftDirectionOfWhereCameraIsFacing = DirectionOfWhereCameraIsFacing; RiftDirectionOfWhereCameraIsFacing = glm::rotate(CurrentOrientation, DirectionOfWhereCameraIsFacing); PositionOfEyesOfPerson += CameraPositionDelta; CenterOfWhatIsBeingLookedAt = PositionOfEyesOfPerson + DirectionOfWhereCameraIsFacing * 1.0f; RiftCenterOfWhatIsBeingLookedAt = PositionOfEyesOfPerson + RiftDirectionOfWhereCameraIsFacing * 1.0f; RiftView = glm::lookAt(PositionOfEyesOfPerson, RiftCenterOfWhatIsBeingLookedAt, DirectionOfUpForPerson);

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  • Faster way to split a string and count characters using R?

    - by chrisamiller
    I'm looking for a faster way to calculate GC content for DNA strings read in from a FASTA file. This boils down to taking a string and counting the number of times that the letter 'G' or 'C' appears. I also want to specify the range of characters to consider. I have a working function that is fairly slow, and it's causing a bottleneck in my code. It looks like this: ## ## count the number of GCs in the characters between start and stop ## gcCount <- function(line, st, sp){ chars = strsplit(as.character(line),"")[[1]] numGC = 0 for(j in st:sp){ ##nested ifs faster than an OR (|) construction if(chars[[j]] == "g"){ numGC <- numGC + 1 }else if(chars[[j]] == "G"){ numGC <- numGC + 1 }else if(chars[[j]] == "c"){ numGC <- numGC + 1 }else if(chars[[j]] == "C"){ numGC <- numGC + 1 } } return(numGC) } Running Rprof gives me the following output: > a = "GCCCAAAATTTTCCGGatttaagcagacataaattcgagg" > Rprof(filename="Rprof.out") > for(i in 1:500000){gcCount(a,1,40)}; > Rprof(NULL) > summaryRprof(filename="Rprof.out") self.time self.pct total.time total.pct "gcCount" 77.36 76.8 100.74 100.0 "==" 18.30 18.2 18.30 18.2 "strsplit" 3.58 3.6 3.64 3.6 "+" 1.14 1.1 1.14 1.1 ":" 0.30 0.3 0.30 0.3 "as.logical" 0.04 0.0 0.04 0.0 "as.character" 0.02 0.0 0.02 0.0 $by.total total.time total.pct self.time self.pct "gcCount" 100.74 100.0 77.36 76.8 "==" 18.30 18.2 18.30 18.2 "strsplit" 3.64 3.6 3.58 3.6 "+" 1.14 1.1 1.14 1.1 ":" 0.30 0.3 0.30 0.3 "as.logical" 0.04 0.0 0.04 0.0 "as.character" 0.02 0.0 0.02 0.0 $sampling.time [1] 100.74 Any advice for making this code faster?

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  • Getting a handle on GIS math, where do I start?

    - by Joshua
    I am in charge of a program that is used to create a set of nodes and paths for consumption by an autonomous ground vehicle. The program keeps track of the locations of all items in its map by indicating the item's position as being x meters north and y meters east of an origin point of 0,0. In the real world, the vehicle knows the location of the origin's lat and long, as it is determined by a dgps system and is accurate down to a couple centimeters. My program is ignorant of any lat long coordinates. It is one of my goals to modify the program to keep track of lat long coords of items in addition to an origin point and items' x,y position in relation to that origin. At first blush, it seems that I am going to modify the program to allow the lat long coords of the origin to be passed in, and after that I desire that the program will automatically calculate the lat long of every item currently in a map. From what I've researched so far, I believe that I will need to figure out the math behind converting to lat long coords from a UTM like projection where I specify the origin points and meridians etc as opposed to whatever is defined already for UTM. I've come to ask of you GIS programmers, am I on the right track? It seems to me like there is so much to wrap ones head around, and I'm not sure if the answer isn't something as simple as, "oh yea theres a conversion from meters to lat long, here" Currently, due to the nature of DGPS, the system really doesn't need to care about locations more than oh, what... 40 km? radius away from the origin. Given this, and the fact that I need to make sure that the error on my coordinates is not greater than .5 meters, do I need anything more complex than a simple lat/long to meters conversion constant? I'm knee deep in materials here. I could use some pointers about what concepts to research. Thanks much!

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  • Animating translation and scaling of view in Android

    - by hgpc
    I have to animate a view from state A to B with changes to its scale, position and scrolling. I know everything about state A (widthA, heightA, topA, leftA, scrollXA, scrollYA) and state B (widthB, heightB, topB, leftB, scrollXB, scrollYB). So far I wrote the following code: AnimationSet animation = new AnimationSet(true); int toXDelta; // What goes here? int toYDelta; // What goes here? TranslateAnimation translateAnimation = new TranslateAnimation(1, toXDelta, 1, toYDelta); translateAnimation.setDuration(duration); animation.addAnimation(translateAnimation); float scale = (float) widthB / (float) widthA; ScaleAnimation scaleAnimation = new ScaleAnimation(1, scale, 1, scale); scaleAnimation.setDuration(duration); animation.addAnimation(scaleAnimation); animation.setAnimationListener(new AnimationListener() { @Override public void onAnimationEnd(Animation arg0) { view.clearAnimation(); // Change view to state B } @Override public void onAnimationRepeat(Animation arg0) {} @Override public void onAnimationStart(Animation arg0) {} }); view.startAnimation(animation); Is this the right way to do this? If so, how should I calculate the values of toXDelta and toYDelta? I'm having trouble finding the exact formula. Thanks!

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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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  • how to get access to private members of nested class?

    - by macias
    Background: I have enclosed (parent) class E with nested class N with several instances of N in E. In the enclosed (parent) class I am doing some calculations and I am setting the values for each instance of nested class. Something like this: n1.field1 = ...; n1.field2 = ...; n1.field3 = ...; n2.field1 = ...; ... It is one big eval method (in parent class). My intention is -- since all calculations are in parent class (they cannot be done per nested instance because it would make code more complicated) -- make the setters only available to parent class and getters public. And now there is a problem: when I make the setters private, parent class cannot acces them when I make them public, everybody can change the values and C# does not have friend concept I cannot pass values in constructor because lazy evaluation mechanism is used (so the instances have to be created when referencing them -- I create all objects and the calculation is triggered on demand) I am stuck -- how to do this (limit access up to parent class, no more, no less)? I suspect I'll get answer-question first -- "but why you don't split the evaluation per each field" -- so I answer this by example: how do you calculate min and max value of a collection? In a fast way? The answer is -- in one pass. This is why I have one eval function which does calculations and sets all fields at once.

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  • Creating a simple JQuery tooltip?

    - by Mike El Panther
    Has anybody here got any experience in creating simple tooptips using JQuery? I have created a table: <tr id="mon_Section"> <td id="day_Title">Monday</td>` <td id="mon_Row" onmousemove="calculate_Time(event)"></td> </tr>` the function "calculate_Time" will be called and this gets the X position of the mouse cursor and from the value, uses IF and ELSE-IF statements to calculate the values of other variables i have created: var mon_Pos; var hour; var minute; var orig; var myxpos; function calculate_Time(event) { myxpos = event.pageX; myxpos = myxpos-194; if (myxpos<60) { orig = myxpos; minute = myxpos; hour = 07; } else if (myxpos>=60 && myxpos<120) { orig = myxpos; minute=myxpos-60; hour=08; } } How do i go about creating a stylized tooltip containing the Hour and Minute variables that i created, I need the tooltip to be updated everytime the X position of the cursor changes. I know that with myxpos variable does change whenever the mouse is moved because i tried it out using an alert(myxpos) and as expected, if the mouse moves, a new alert box popups with a new value. I just cant work out how to place that value in a tooltip?

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  • I can't read the value from a radio button.

    - by Corey
    <html> <head> <title>Tip Calculator</title> <script type="text/javascript"><!-- function calculateBill(){ var check = document.getElementById("check").value; /* I try to get the value selected */ var tipPercent = document.getElementById("tipPercent").value; /* But it always returns the value 15 */ var tip = check * (tipPercent / 100) var bill = 1 * check + tip; document.getElementById('bill').innerHTML = bill; } --></script> </head> <body> <h1 style="text-align:center">Tip Calculator</h1> <form id="f1" name="f1"> Average Sevice: 15%<input type="radio" id="tipPercent" name="tipPercent" value="15" /> <br /> Excellent Sevice: 20%<input type="radio" id="tipPercent" name="tipPercent" value="20" /> <br /><br /> <label>Check Amount</label> <input type="text" id="check" size="10" /> <input type="button" onclick="calculateBill()" value="Calculate" /> </form> <br /> Total Bill: <p id="bill"></p> </body> </html>

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  • count how many days within a date range are within another date range

    - by joko13
    From October 1st to March 31 the fee is $1 (season 1). From April 1st to September 30 the fee is $2 (season 2). How can I calculate the total fee of a given date range (user input) depending on how many days of this date range fall into season 1 and season 2? The following gives me the number of days of the user´s date range, but I have no idea how to test against season 1 or season 2: $user_input_start_date = getdate( $a ); $user_input_end_date = getdate( $b ); $start_date_new = mktime( 12, 0, 0, $user_input_start_date['mon'], $user_input_start_date['mday'], $user_input_start_date['year'] ); $end_date_new = mktime( 12, 0, 0, $user_input_end_date['mon'], $user_input_end_date['mday'], $user_input_end_date['year'] ); return round( abs( $start_date_new - $end_date_new ) / 86400 ); Thanks for your help! EDIT: Given that a date range starts and ends in 2012 or starts in 2012 and ends in 2013 alone gives me 10 different possibilities of in which season a date range can start and where it can end. There must be a better solution than iterating if/else and comparing dates over and over again for the following conditions: Date range is completely within season 1 Date range starts in season 1 and ends in season 2 Date range starts in season 1, spans across season 2 and ends in the second part of season 1 ... and so forth with "Starts in season 2", etc

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  • Jquery Bugs?? Long decimal number after two numbers multiply...

    - by Jerry
    Hi all I am working on a shopping site and I am trying to calculate the subtotal of products. I got my price from a array and quantity from getJSON response array. Two of them multiply comes to my subtotal. I can change the quantity and it will comes out different subtotal. However,when I change the quantity to certain number, the final subtotal is like 259.99999999994 or some long decimal number. I use console.log to check the $price and $qty. Both of them are in the correct format ex..299.99 and 6 quantity.I have no idea what happen. I would appreciate it if someone can help me about it. Here is my Jquery code. $(".price").each(function(index, price){ $price=$(this); //get the product id and the price shown on the page var id=$price.closest('tr').attr('id'); var indiPrice=$($price).html(); //take off $ indiPrice=indiPrice.substring(1) //make sure it is number format var aindiPrice=Number(indiPrice); //push into the array productIdPrice[id]=(aindiPrice); var url=update.php $.getJSON( url, {productId:tableId, //tableId is from the other jquery code which refers to qty:qty}, productId function(responseProduct){ $.each(responseProduct, function(productIndex, Qty){ //loop the return data if(productIdPrice[productIndex]){ //get the price from the previous array we create X Qty newSub=productIdPrice[productIndex]*Number(Qty); //productIdPrice[productIndex] are the price like 199.99 or 99.99 // Qty are Quantity like 9 or 10 or 3 sum+=newSub; newSub.toFixed(2); //try to solve the problem with toFixed but didn't work console.log("id: "+productIdPrice[productIndex]) console.log("Qty: "+Qty); console.log(newSub); **//newSub sometime become XXXX.96999999994** }; Thanks again!

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  • Graphical glitches when adding cells and scrolling with UITableView

    - by Daniel I-S
    I am using a UITableView to display the results of a series of calculations. When the user hits 'calculate', I wish to add the latest result to the screen. This is done by adding a new cell to a 'results' section. The UITableViewCell object is added to an array, and then I use the following code to add this new row to what is displayed on the screen: [thisView beginUpdates]; [thisView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath] withRowAnimation: UITableViewRowAnimationFade]; [thisView endUpdates]; This results in the new cell being displayed. However, I then want to immediately scroll the screen down so that the new cell is the lowermost cell on-screen. I use the following code: [thisView scrollToRowAtIndexPath:newIndexPath atScrollPosition:UITableViewScrollPositionBottom animated:YES]; This almost works great. However, the first time a cell is added and scrolled to, it appears onscreen only briefly before vanishing. The view scrolls down to the correct place, but the cell is not there. Scrolling the view by hand until this invisible new cell's position is offscreen, then back again, causes the cell to appear - after which it behaves normally. This only happens the first time a cell is added; subsequent cells don't have this problem. It also happens regardless of the combination of scrollToRowAtIndexPath and insertRowsAtIndexPath animation settings. There is also a problem where, if new cells are added repeatedly and quickly, the new cells stop 'connecting up'. The lowermost cell in a group is supposed to have rounded corners, and when a new cell is added these turn into square corners so that there is a clean join with the next cell in the group. In this case, however, a cell often does not lose its rounded edges despite not being the last cell anymore. This also gets corrected once the affected area moves offscreen and back. This method of adding and scrolling would be perfect for my application if it weren't for these weird glitches. Any ideas as to what I may be doing wrong?

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  • How do i get the screen to pause?

    - by Dakota
    So im learning c++ and i was given this example and i wanted to run it. But i cannot get it to stay up, unless i change it. How do i get Microsoft visual 2010 to keep up the screen when it gets to the end of the program after I release it? include using namespace std; int area(int length, int width); /* function declaration */ /* MAIN PROGRAM: */ int main() { int this_length, this_width; cout << "Enter the length: "; /* <--- line 9 */ cin >> this_length; cout << "Enter the width: "; cin >> this_width; cout << "\n"; /* <--- line 13 */ cout << "The area of a " << this_length << "x" << this_width; cout << " rectangle is " << area(this_length, this_width); return 0; } /* END OF MAIN PROGRAM */ /* FUNCTION TO CALCULATE AREA: */ int area(int length, int width) /* start of function definition */ { int number; number = length * width; return number; } /* end of function definition */ /* END OF FUNCTION */

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  • The mathematics of Schellings segregation model

    - by Bruce
    For those who don't know the model. You can read this pdf. I want to find what is the probability that 2 nodes are each others neighbors when the algorithm converges (i.e. when all nodes are happy). Here's the model in a gist. You have a grid (say 10x10). You have nodes of two kind (red and green) 45 each. So we have 10 empty spaces. We randomly place the nodes on the grid. Now we scan through this grid (Exact order does not matter according to Schelling). Each node wants a specific percentage of people of same kind in its Moore neighborhood (say b = 50% for each red and green). We calculate the happiness of each node (a = Number of neighbors of same kind/Number of neighbors of different kind). If a node is unhappy (a < b) it moves to an empty cell where it knows it will be happy. This movement can change the dynamics of old as well as new neighborhood. Algorithm converges when all nodes are happy. PS - I am looking for links for any mathematical analysis of the Schelling's model.

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  • Drawing an honeycomb with as3

    - by vitto
    Hi, I'm trying to create an honeycomb with as3 but I have some problem on cells positioning. I've already created the cells (not with code) and for cycled them to a funcion and send to it the parameters which what I thought was need (the honeycomb cell is allready on a sprite container in the center of the stage). to see the structure of the cycle and which parameters passes, please see the example below, the only thing i calculate in placeCell is the angle which I should obtain directly inside tha called function Note: the angle is reversed but it isn't important, and the color are useful in example only for visually divide cases. My for cycle calls placeCell and passes cell, current_case, counter (index) and the honeycomb cell_lv (cell level). I thought it was what i needed but I'm not skilled in geometry and trigonometry, so I don't know how to position cells correctly: function placeCell (cell:Sprite, current_case:int, counter:int, cell_lv:int):void { var margin:int = 2; var angle:Number = (360 / (cell_lv * 6)) * (current_case + counter); var radius:Number = (cell.width + margin) * cell_lv; cell.x = radius * Math.cos (angle); cell.y = radius * Math.sin (angle); trace ("LV " + cell_lv + " current_case " + current_case + " counter " + counter + " angle " + angle + " radius " + radius) } how can I do to solve it?

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  • Android Compass orientation on unreliable (Low pass filter)

    - by madsleejensen
    Hi all Im creating an application where i need to position a ImageView depending on the Orientation of the device. I use the values from a MagneticField and Accelerometer Sensors to calculate the device orientation with SensorManager.getRotationMatrix(rotationMatrix, null, accelerometerValues, magneticFieldValues) SensorManager.getOrientation(rotationMatrix, values); double degrees = Math.toDegrees(values[0]); My problem is that the positioning of the ImageView is very sensitive to changes in the orientation. Making the imageview constantly jumping around the screen. (because the degrees change) I read that this can be because my device is close to things that can affect the magneticfield readings. But this is not the only reason it seems. I tried downloading some applications and found that the "3D compass" application remains extremely steady in its readings, i would like the same behavior in my application. I read that i can tweak the "noise" of my readings by adding a "Low pass filter", but i have no idea how to implement this (because of my lack of Math). Im hoping someone can help me creating a more steady reading on my device, Where a little movement to the device wont affect the current orientation. Right now i do a small if (Math.abs(lastReadingDegrees - newReadingDegrees) > 1) { updatePosition() } To filter abit of the noise. But its not working very well :)

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  • Implementing a scrabble trainer

    - by bstullkid
    Hello, I've recently been playing alot of online scrabble so I decided to make a program that quickly searches through a dictionary of 200,000+ words with an input of up to any 26 letters. My first attempt was fail as it took a while when you input 8 or more letters (just a basic look through dictionary and cancel out a letter if its found kind of thing), so I made a tree like structure containing only an array of 26 of the same structure and a flag to indicate the end of a word, doing that It can output all possible words in under a second even with an input of 26 characters. But it seems that when I input 12 or more letters with some of the same characters repeated i get duplicates; can anyone see why I would be getting duplicates with this code? (ill post my program at the bottom) Also, the next step once the duplicates are weeded out is to actually be able to input the letters on the game board and then have it calculate the best word you can make on a given board. I am having trouble trying to figure out a good algorithm that can analyze a scrabble board and an input of letters and output a result; the possible words that could be made I have no problem with but actually checking a board efficiently (ie can this word fit here, or here etc... without creating a non dictionary word in the process on some other string of letters) Anyone have a idea for an approach at that? (given a scrabble board, and an input of 7 letters, find all possible valid words or word sets that you can make) lol crap i forgot to email myself the code from my other computer thats in another state... ill post it on monday when I get back there! btw the dictionary im using is sowpods (http://www.calvin.edu/~rpruim/scrabble/ospd3.txt)

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  • What is wrong with accessing DBI directly?

    - by canavanin
    Hi everyone! I'm currently reading Effective Perl Programming (2nd edition). I have come across a piece of code which was described as being poorly written, but I don't yet understand what's so bad about it, or how it should be improved. It would be great if someone could explain the matter to me. Here's the code in question: sub sum_values_per_key { my ( $class, $dsn, $user, $password, $parameters ) = @_; my %results; my $dbh = DBI->connect( $dsn, $user, $password, $parameters ); my $sth = $dbh->prepare( 'select key, calculate(value) from my_table'); $sth->execute(); # ... fill %results ... $sth->finish(); $dbh->disconnect(); return \%results; } The example comes from the chapter on testing your code (p. 324/325). The sentence that has left me wondering about how to improve the code is the following: Since the code was poorly written and accesses DBI directly, you'll have to create a fake DBI object to stand in for the real thing. I have probably not understood a lot of what the book has so far been trying to teach me, or I have skipped the section relevant for understanding what's bad practice about the above code... Well, thanks in advance for your help!

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  • Remove redundant SQL code

    - by Dave Jarvis
    Code The following code calculates the slope and intercept for a linear regression against a slathering of data. It then applies the equation y = mx + b against the same result set to calculate the value of the regression line for each row. Can the two separate sub-selects be joined so that the data and its slope/intercept are calculated without executing the data gathering part of the query twice? SELECT AVG(D.AMOUNT) as AMOUNT, Y.YEAR * ymxb.SLOPE + ymxb.INTERCEPT as REGRESSION_LINE, Y.YEAR as YEAR, MAKEDATE(Y.YEAR,1) as AMOUNT_DATE FROM CITY C, STATION S, YEAR_REF Y, MONTH_REF M, DAILY D, (SELECT ((avg(t.AMOUNT * t.YEAR)) - avg(t.AMOUNT) * avg(t.YEAR)) / (stddev( t.AMOUNT ) * stddev( t.YEAR )) as CORRELATION, ((sum(t.YEAR) * sum(t.AMOUNT)) - (count(1) * sum(t.YEAR * t.AMOUNT))) / (power(sum(t.YEAR), 2) - count(1) * sum(power(t.YEAR, 2))) as SLOPE, ((sum( t.YEAR ) * sum( t.YEAR * t.AMOUNT )) - (sum( t.AMOUNT ) * sum(power(t.YEAR, 2)))) / (power(sum(t.YEAR), 2) - count(1) * sum(power(t.YEAR, 2))) as INTERCEPT FROM ( SELECT AVG(D.AMOUNT) as AMOUNT, Y.YEAR as YEAR, MAKEDATE(Y.YEAR,1) as AMOUNT_DATE FROM CITY C, STATION S, YEAR_REF Y, MONTH_REF M, DAILY D WHERE $X{ IN, C.ID, CityCode } AND SQRT( POW( C.LATITUDE - S.LATITUDE, 2 ) + POW( C.LONGITUDE - S.LONGITUDE, 2 ) ) < $P{Radius} AND S.STATION_DISTRICT_ID = Y.STATION_DISTRICT_ID AND Y.YEAR BETWEEN 1900 AND 2009 AND M.YEAR_REF_ID = Y.ID AND M.CATEGORY_ID = $P{CategoryCode} AND M.ID = D.MONTH_REF_ID AND D.DAILY_FLAG_ID <> 'M' GROUP BY Y.YEAR ) t ) ymxb WHERE $X{ IN, C.ID, CityCode } AND SQRT( POW( C.LATITUDE - S.LATITUDE, 2 ) + POW( C.LONGITUDE - S.LONGITUDE, 2 ) ) < $P{Radius} AND S.STATION_DISTRICT_ID = Y.STATION_DISTRICT_ID AND Y.YEAR BETWEEN 1900 AND 2009 AND M.YEAR_REF_ID = Y.ID AND M.CATEGORY_ID = $P{CategoryCode} AND M.ID = D.MONTH_REF_ID AND D.DAILY_FLAG_ID <> 'M' GROUP BY Y.YEAR Question How do I execute the duplicate bits only once per query, instead of twice? The duplicate bit is the WHERE clause: $X{ IN, C.ID, CityCode } AND SQRT( POW( C.LATITUDE - S.LATITUDE, 2 ) + POW( C.LONGITUDE - S.LONGITUDE, 2 ) ) < $P{Radius} AND S.STATION_DISTRICT_ID = Y.STATION_DISTRICT_ID AND Y.YEAR BETWEEN 1900 AND 2009 AND M.YEAR_REF_ID = Y.ID AND M.CATEGORY_ID = $P{CategoryCode} AND M.ID = D.MONTH_REF_ID AND D.DAILY_FLAG_ID <> 'M' Related http://stackoverflow.com/questions/1595659/how-to-eliminate-duplicate-calculation-in-sql Thank you!

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  • Using hashing to group similar records

    - by Neil Dobson
    I work for a fulfillment company and we have to pack and ship many orders from our warehouse to customers. To improve efficiency we would like to group identical orders and pack these in the most optimum way. By identical I mean having the same number of order lines containing the same SKUs and same order quantities. To achieve this I was thinking about hashing each order. We can then group by hash to quickly see which orders are the same. We are moving from an Access database to a PostgreSQL database and we have .NET based systems for data loading and general order processing systems, so we can either do the hashing during the data loading or hand this task over to the DB. My question firstly is should the hashing be managed by DB, possibly using triggers, or should the hash be created on-the-fly using a view or something? And secondly would it be best to calculate a hash for each order line and then to combine these to find an order-level hash for grouping, or should I just use a trigger for all CRUD operations on the order lines table which re-calculates a single hash for the entire order and store the value in the orders table? TIA

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  • OpenCL - incremental summation during compute

    - by user1721997
    I'm absolutelly novice in OpenCL programming. For my app. (molecular simulaton) I wrote a kernel for calculate intermolecular potential of lennard-jones liquid. In this kernel I need to compute cumulative value of the potential of all particles with one: __kernel void Molsim(__global const float* inmatrix, __global float* fi, const int c, const float r1, const float r2, const float r3, const float rc, const float epsilon, const float sigma, const float h1, const float h23) { float fi0; float fi1; float d; unsigned int i = get_global_id(0); //number of particles (typically 2000) if(c!=i) { // potential before particle movement d=sqrt(pow((0.5*h1-fabs(0.5*h1-fabs(inmatrix[c*3]-inmatrix[i*3]))),2.0)+pow((0.5*h23-fabs(0.5*h23-fabs(inmatrix[c*3+1]-inmatrix[i*3+1]))),2.0)+pow((0.5*h23-fabs(0.5*h23-fabs(inmatrix[c*3+2]-inmatrix[i*3+2]))),2.0)); if(d<rc) { fi0=4.0*epsilon*(pow(sigma/d,12.0)-pow(sigma/d,6.0)); } else { fi0=0; } // potential after particle movement d=sqrt(pow((0.5*h1-fabs(0.5*h1-fabs(r1-inmatrix[i*3]))),2.0)+pow((0.5*h23-fabs(0.5*h23-fabs(r2-inmatrix[i*3+1]))),2.0)+pow((0.5*h23-fabs(0.5*h23-fabs(r3-inmatrix[i*3+2]))),2.0)); if(d<rc) { fi1=4.0*epsilon*(pow(sigma/d,12.0)-pow(sigma/d,6.0)); } else { fi1=0; } // cumulative difference of potentials fi[0]+=fi1-fi0; } } My problem is in the line: fi[0]+=fi1-fi0;. In the one-element vector fi[0] are wrong results. I read something about sum reduction, but I do not know how to do it during the calculation. Exist any simple solution of my problem?

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