Search Results

Search found 22128 results on 886 pages for 'point in polygon'.

Page 33/886 | < Previous Page | 29 30 31 32 33 34 35 36 37 38 39 40  | Next Page >

  • Counting point size based on chart area during zooming/unzoomin

    - by Gacek
    Hi folks. I heave a quite simple task. I know (I suppose) it should be easy, but from the reasons I cannot understand, I try to solve it since 2 days and I don't know where I'm making the mistake. So, the problem is as follows: - we have a chart with some points - The chart starts with some known area and points have known size - we would like to "emulate" the zooming effect. So when we zoom to some part of the chart, the size of points is getting proportionally bigger. In other words, the smaller part of the chart we select, the bigger the point should get. So, we have something like that. We know this two parameters: initialArea; // Initial area - area of the whole chart, counted as width*height initialSize; // initial size of the points Now lets assume we are handling some kind of OnZoom event. We selected some part of the chart and would like to count the current size of the points float CountSizeOnZoom() { float currentArea = CountArea(...); // the area is counted for us. float currentSize = initialSize * initialArea / currentArea; return currentSize; } And it works. But the rate of change is too fast. In other words, the points are getting really big too soon. So I would like the currentSize to be invertly proportional to currentArea, but with some scaling coefficient. So I created the second function: float CountSizeOnZoom() { float currentArea = CountArea(...); % the area is counted for us. // Lets assume we want the size of points to change ten times slower, than area of the chart changed. float currentSize = initialSize + 0.1f* initialSize * ((initialArea / currentArea) -1); return currentSize; } Lets do some calculations in mind. if currentArea is smaller than initialArea, initialArea/currentArea > 1 and then we add "something" small and postive to initialSize. Checked, it works. Lets check what happens if we would un-zoom. currentArea will be equal to initialArea, so we would have 0 at the right side (1-1), so new size should be equal to initialSize. Right? Yeah. So lets check it... and it doesn't work. My question is: where is the mistake? Or maybe you have any ideas how to count this scaled size depending on current area in some other way?

    Read the article

  • How to manually (bitwise) perform (float)x? (homework)

    - by Silver
    Now, here is the function header of the function I'm supposed to implement: /* * float_from_int - Return bit-level equivalent of expression (float) x * Result is returned as unsigned int, but * it is to be interpreted as the bit-level representation of a * single-precision floating point values. * Legal ops: Any integer/unsigned operations incl. ||, &&. also if, while * Max ops: 30 * Rating: 4 */ unsigned float_from_int(int x) { ... } We aren't allowed to do float operations, or any kind of casting. Now I tried to implement the first algorithm given at this site: http://locklessinc.com/articles/i2f/ Here's my code: unsigned float_from_int(int x) { // grab sign bit int xIsNegative = 0; int absValOfX = x; if(x < 0){ xIsNegative = 1; absValOfX = -x; } // zero case if(x == 0){ return 0; } //int shiftsNeeded = 0; /*while(){ shiftsNeeded++; }*/ unsigned I2F_MAX_BITS = 15; unsigned I2F_MAX_INPUT = ((1 << I2F_MAX_BITS) - 1); unsigned I2F_SHIFT = (24 - I2F_MAX_BITS); unsigned result, i, exponent, fraction; if ((absValOfX & I2F_MAX_INPUT) == 0) result = 0; else { exponent = 126 + I2F_MAX_BITS; fraction = (absValOfX & I2F_MAX_INPUT) << I2F_SHIFT; i = 0; while(i < I2F_MAX_BITS) { if (fraction & 0x800000) break; else { fraction = fraction << 1; exponent = exponent - 1; } i++; } result = (xIsNegative << 31) | exponent << 23 | (fraction & 0x7fffff); } return result; } But it didn't work (see test error below): Test float_from_int(-2147483648[0x80000000]) failed... ...Gives 0[0x0]. Should be -822083584[0xcf000000] 4 4 0 float_times_four I don't know where to go from here. How should I go about parsing the float from this int?

    Read the article

  • Round-twice error in .NET's Double.ToString method

    - by Jeppe Stig Nielsen
    Mathematically, consider for this question the rational number 8725724278030350 / 2**48 where ** in the denominator denotes exponentiation, i.e. the denominator is 2 to the 48th power. (The fraction is not in lowest terms, reducible by 2.) This number is exactly representable as a System.Double. Its decimal expansion is 31.0000000000000'49'73799150320701301097869873046875 (exact) where the apostrophes do not represent missing digits but merely mark the boudaries where rounding to 15 resp. 17 digits is to be performed. Note the following: If this number is rounded to 15 digits, the result will be 31 (followed by thirteen 0s) because the next digits (49...) begin with a 4 (meaning round down). But if the number is first rounded to 17 digits and then rounded to 15 digits, the result could be 31.0000000000001. This is because the first rounding rounds up by increasing the 49... digits to 50 (terminates) (next digits were 73...), and the second rounding might then round up again (when the midpoint-rounding rule says "round away from zero"). (There are many more numbers with the above characteristics, of course.) Now, it turns out that .NET's standard string representation of this number is "31.0000000000001". The question: Isn't this a bug? By standard string representation we mean the String produced by the parameterles Double.ToString() instance method which is of course identical to what is produced by ToString("G"). An interesting thing to note is that if you cast the above number to System.Decimal then you get a decimal that is 31 exactly! See this Stack Overflow question for a discussion of the surprising fact that casting a Double to Decimal involves first rounding to 15 digits. This means that casting to Decimal makes a correct round to 15 digits, whereas calling ToSting() makes an incorrect one. To sum up, we have a floating-point number that, when output to the user, is 31.0000000000001, but when converted to Decimal (where 29 digits are available), becomes 31 exactly. This is unfortunate. Here's some C# code for you to verify the problem: static void Main() { const double evil = 31.0000000000000497; string exactString = DoubleConverter.ToExactString(evil); // Jon Skeet, http://csharpindepth.com/Articles/General/FloatingPoint.aspx Console.WriteLine("Exact value (Jon Skeet): {0}", exactString); // writes 31.00000000000004973799150320701301097869873046875 Console.WriteLine("General format (G): {0}", evil); // writes 31.0000000000001 Console.WriteLine("Round-trip format (R): {0:R}", evil); // writes 31.00000000000005 Console.WriteLine(); Console.WriteLine("Binary repr.: {0}", String.Join(", ", BitConverter.GetBytes(evil).Select(b => "0x" + b.ToString("X2")))); Console.WriteLine(); decimal converted = (decimal)evil; Console.WriteLine("Decimal version: {0}", converted); // writes 31 decimal preciseDecimal = decimal.Parse(exactString, CultureInfo.InvariantCulture); Console.WriteLine("Better decimal: {0}", preciseDecimal); // writes 31.000000000000049737991503207 } The above code uses Skeet's ToExactString method. If you don't want to use his stuff (can be found through the URL), just delete the code lines above dependent on exactString. You can still see how the Double in question (evil) is rounded and cast.

    Read the article

  • Anything wrong with this function for comparing floats?

    - by Michael Borgwardt
    When my Floating-Point Guide was yesterday published on slashdot, I got a lot of flak for my suggested comparison function, which was indeed inadequate. So I finally did the sensible thing and wrote a test suite to see whether I could get them all to pass. Here is my result so far. And I wonder if this is really as good as one can get with a generic (i.e. not application specific) float comparison function, or whether I still missed some edge cases. import static org.junit.Assert.assertFalse; import static org.junit.Assert.assertTrue; import org.junit.Test; public class NearlyEqualsTest { public static boolean nearlyEqual(float a, float b) { final float epsilon = 0.000001f; final float absA = Math.abs(a); final float absB = Math.abs(b); final float diff = Math.abs(a-b); if (a*b==0) { // a or b or both are zero // relative error is not meaningful here return diff < Float.MIN_VALUE / epsilon; } else { // use relative error return diff / (absA+absB) < epsilon; } } /** Regular large numbers - generally not problematic */ @Test public void big() { assertTrue(nearlyEqual(1000000f, 1000001f)); assertTrue(nearlyEqual(1000001f, 1000000f)); assertFalse(nearlyEqual(10000f, 10001f)); assertFalse(nearlyEqual(10001f, 10000f)); } /** Negative large numbers */ @Test public void bigNeg() { assertTrue(nearlyEqual(-1000000f, -1000001f)); assertTrue(nearlyEqual(-1000001f, -1000000f)); assertFalse(nearlyEqual(-10000f, -10001f)); assertFalse(nearlyEqual(-10001f, -10000f)); } /** Numbers around 1 */ @Test public void mid() { assertTrue(nearlyEqual(1.0000001f, 1.0000002f)); assertTrue(nearlyEqual(1.0000002f, 1.0000001f)); assertFalse(nearlyEqual(1.0002f, 1.0001f)); assertFalse(nearlyEqual(1.0001f, 1.0002f)); } /** Numbers around -1 */ @Test public void midNeg() { assertTrue(nearlyEqual(-1.000001f, -1.000002f)); assertTrue(nearlyEqual(-1.000002f, -1.000001f)); assertFalse(nearlyEqual(-1.0001f, -1.0002f)); assertFalse(nearlyEqual(-1.0002f, -1.0001f)); } /** Numbers between 1 and 0 */ @Test public void small() { assertTrue(nearlyEqual(0.000000001000001f, 0.000000001000002f)); assertTrue(nearlyEqual(0.000000001000002f, 0.000000001000001f)); assertFalse(nearlyEqual(0.000000000001002f, 0.000000000001001f)); assertFalse(nearlyEqual(0.000000000001001f, 0.000000000001002f)); } /** Numbers between -1 and 0 */ @Test public void smallNeg() { assertTrue(nearlyEqual(-0.000000001000001f, -0.000000001000002f)); assertTrue(nearlyEqual(-0.000000001000002f, -0.000000001000001f)); assertFalse(nearlyEqual(-0.000000000001002f, -0.000000000001001f)); assertFalse(nearlyEqual(-0.000000000001001f, -0.000000000001002f)); } /** Comparisons involving zero */ @Test public void zero() { assertTrue(nearlyEqual(0.0f, 0.0f)); assertFalse(nearlyEqual(0.00000001f, 0.0f)); assertFalse(nearlyEqual(0.0f, 0.00000001f)); } /** Comparisons of numbers on opposite sides of 0 */ @Test public void opposite() { assertFalse(nearlyEqual(1.000000001f, -1.0f)); assertFalse(nearlyEqual(-1.0f, 1.000000001f)); assertFalse(nearlyEqual(-1.000000001f, 1.0f)); assertFalse(nearlyEqual(1.0f, -1.000000001f)); assertTrue(nearlyEqual(10000f*Float.MIN_VALUE, -10000f*Float.MIN_VALUE)); } /** * The really tricky part - comparisons of numbers * very close to zero. */ @Test public void ulp() { assertTrue(nearlyEqual(Float.MIN_VALUE, -Float.MIN_VALUE)); assertTrue(nearlyEqual(-Float.MIN_VALUE, Float.MIN_VALUE)); assertTrue(nearlyEqual(Float.MIN_VALUE, 0)); assertTrue(nearlyEqual(0, Float.MIN_VALUE)); assertTrue(nearlyEqual(-Float.MIN_VALUE, 0)); assertTrue(nearlyEqual(0, -Float.MIN_VALUE)); assertFalse(nearlyEqual(0.000000001f, -Float.MIN_VALUE)); assertFalse(nearlyEqual(0.000000001f, Float.MIN_VALUE)); assertFalse(nearlyEqual(Float.MIN_VALUE, 0.000000001f)); assertFalse(nearlyEqual(-Float.MIN_VALUE, 0.000000001f)); assertFalse(nearlyEqual(1e20f*Float.MIN_VALUE, 0.0f)); assertFalse(nearlyEqual(0.0f, 1e20f*Float.MIN_VALUE)); assertFalse(nearlyEqual(1e20f*Float.MIN_VALUE, -1e20f*Float.MIN_VALUE)); } }

    Read the article

  • How can I convert a 2D bitmap (Used for terrain) to a 2D polygon mesh for collision?

    - by Megadanxzero
    So I'm making an artillery type game, sort of similar to Worms with all the usual stuff like destructible terrain etc... and while I could use per-pixel collision that doesn't give me collision normals or anything like that. Converting it all to a mesh would also mean I could use an existing physics library, which would be better than anything I can make by myself. I've seen people mention doing this by using Marching Squares to get contours in the bitmap, but I can't find anything which mentions how to turn these into a mesh (Unless it refers to a 3D mesh with contour lines defining different heights, which is NOT what I want). At the moment I can get a basic Marching Squares contour which looks something like this (Where the grid-like lines in the background would be the Marching Squares 'cells'): That needs to be interpolated to get a smoother, more accurate result but that's the general idea. I had a couple ideas for how to turn this into a mesh, but many of them wouldn't work in certain cases, and the one which I thought would work perfectly has turned out to be very slow and I've not even finished it yet! Ideally I'd like whatever I end up using to be fast enough to do every frame for cases such as rapidly-firing weapons, or digging tools. I'm thinking there must be some kind of existing algorithm/technique for turning something like this into a mesh, but I can't seem to find anything. I've looked at some things like Delaunay Triangulation, but as far as I can tell that won't correctly handle concave shapes like the above example, and also wouldn't account for holes within the terrain. I'll go through the technique I came up with for comparison and I guess I'll see if anyone has a better idea. First of all interpolate the Marching Squares contour lines, creating vertices from the line ends, and getting vertices where lines cross cell edges (Important). Then, for each cell containing vertices create polygons by using 2 vertices, and a cell corner as the 3rd vertex (Probably the closest corner). Do this for each cell and I think you should have a mesh which accurately represents the original bitmap (Though there will only be polygons at the edges of the bitmap, and large filled in areas in between will be empty). The only problem with this is that it involves lopping through every pixel once for the initial Marching Squares, then looping through every cell (image height + 1 x image width + 1) at least twice, which ends up being really slow for any decently sized image...

    Read the article

  • Des chercheurs en sécurité découvrent Dexter, un malware qui cible essentiellement les systèmes de point de vente

    Des chercheurs en sécurité découvrent Dexter un malware qui cible essentiellement les systèmes de point de vente Les pirates pour voler les données des cartes de crédit ont trouvé un moyen d'insérer un malware directement dans les systèmes de point de vente (POS). La firme de sécurité Seculert vient d'identifier un programme malveillant spécialement conçu pour attaquer les systèmes de point de vente. Le logiciel malveillant baptisé Dexter, aurait déjà infecté des systèmes POS dans près de 40 pays au cours des deux derniers mois. Les pays anglo-saxons semblent être les cibles favorites du malware, avec 30% d'attaque aux USA, 19% en Grande-Bretagne et 9% au Canada. L...

    Read the article

  • Epson OPOS ADK for .NET drivers for windows 7

    - by Xience
    Has anyone used Epson OPOS ADK for .NET for windows 7. i tried to install windows vista drivers on windows 7, since there are none available for windows 7, but it did not work. Please share any suggestions or ideas that might have worked for you. I am using a TM-88IV receipt printer

    Read the article

  • MS cash drawer with epson TM-IV88 Status API

    - by Xience
    Does anyone know how to monitor cash drawer's open/close state using Advanced Printer Driver's Status API for Epson TM-88IV thermal printer. I wish i could use OPOS for ADK .Net, but haven't had luck setting it up on windows 7. Does anyone know how to be a part of epson developer network. I have gone through the information available at www.epson-pos.com but there is no information available on POS/ESC codes. Please help...........

    Read the article

  • Read half precision float (float16 IEEE 754r) binary data in matlab

    - by Michael
    you have been a great help last time, i hope you can give me some advise this time, too. I read a binary file into matlab with bit16 (format = bitn) and i get a string of ones and zeros. bin = '1 00011 1111111111' (16 bits: 1. sign, 2-6. exponent, 7-16. mantissa) According to ftp://www.fox-toolkit.org/pub/fasthalffloatconversion.pdf it can be 'converted' like out = (-1)^bin(1) * 2^(bin(2:6)-15) * 1.bin(7:16) [are exponent and mantissa still binary?] Can someone help me out and tell me how to deal with the 'eeeee' and '1.mmmmmmmmmm' as mentioned in the pdf, please. Thanks a lot! Michael

    Read the article

  • dividing double by double gives weird results - Java

    - by Aly
    Hi, I am trying to do the following 33.33333333333333/100.0 to get 0.333333333333333 however when I run System.out.println(33.33333333333333/100.0); I get 0.33333333333333326 as the output, similarly when I run System.out.println(33.33333333333333/1000.0); I get 0.033333333333333326 as the output. Does anyone know why, and how I can get the correct value (without loss of decimal places). Thanks

    Read the article

  • MIPS (or SPIM): Loading floating point numbers...

    - by James
    Hey hey, I am working on a little mini compiler while trying to learn some MIPS here. Here's my issue: MIPS has an instruction li (load immediate) which would work like this li $5,100 which would load 100 into register 5. However, I need to load floats into registers right now and am struggling with figuring out a way to do it...since li $5,2.5 does not work. Anyone have any advice? I am working in C, I was thinking I could somehow get the integer representation of the float I am working with (i.e. so the floats binary representation == the ints binary representation) then load the "integer" into the register and treat it like a float from then on. Maybe its too late but Im stuck right now.

    Read the article

  • Controlling FPU behavior in an OpenMP program?

    - by STingRaySC
    I have a large C++ program that modifies the FPU control word (using _controlfp()). It unmasks some FPU exceptions and installs a SEHTranslator to produce typed C++ exceptions. I am using VC++ 9.0. I would like to use OpenMP (v.2.0) to parallelize some of our computational loops. I've already successfully applied it to one, but the numerical results are slightly different (though I understand it could also be due to calculations being performed in a different order). I'm assuming this is because the FPU state is thread-specific. Is there some way to have the OpenMP threads inherit that state from the master thread? Or is there some way to specify using OpenMP that new threads execute a particular function that sets up the correct state? What is the idiomatic way to deal with this situation?

    Read the article

  • Insert some data at later point once serialization(binary serialization) is done for a class

    - by coolcake
    My application is written in C# and I am a newbie to C#. I am facing with a problem during serialization. The problem is as follows. There are many classes in my project and when serialization is called on one of the main class object it serializes itself and during this process many of the member objects are also get serialized. This whole serialization is done in to a file with extension say ".bin". This bin file size should be of size max 20MB. In this process of serialization one of my other class also gets serialized to a stream, this class is having a big array. The size of this array or list can be of 80 MB or more. So during serialization i have serialize all the objects other than this array and depending upon the size left in the 20MB I need to add in between the serialization the number of array elements which can fit in the remaining memory. For the other array elements left out I have to create a similar kind of .bin file with all the objects serialized and in between need to insert the number of array elements that can fit there. The main problem here is the array elements get inserted at runtime and this list keeps on increasing. So i should be creating .bin files continuously until my application runs. Any ideas how can i implement a solution for this problem? Thanks in Advance.

    Read the article

  • Detecting wether a point is inside or outside of a raphael.js shape

    - by betamax
    I have a raphael.js shape which I am plotting circle's on top of. I only want a circle to appear if the circle does not go off the boundary of the shape it is being plotted on to. To make this more clear, here is an example of what I do not want to happen: I want the circles outside of the grey area not to appear. How would I detect wether a circle is inside or outside of the grey shape?

    Read the article

  • Configuring a POS printer using POS.NET

    - by codeincarnate
    Is it possible to configure a POS printer service object (an Epson one) from a POS.NET application (such as configuring the IP address for a network connected printer)? It would be nice if it didn't need to be done separately through the applications that Epson provides.

    Read the article

  • serverside controls vs html controls from AJAX point of view

    - by devmania
    hi, i know this question have been mentioned alot here but mine is a little more updated, now with ASP.net 4 and new Ajax client templating plus JASON services. so if i got all these new capabilities will i really need server side controls as long as i can bind on client side, create data-views on client side heck i can even use data-context and apply CRUD operations on clients side. so i actually i wont need button_click server side event or what so ever... i am asking this because i own some commercial Controls like Telerik and Component art and they both offer client side operations ow but still i am confused as to my knowledge creating these controls will still have to go through Page Life cycle please advise me.

    Read the article

  • CUDA: accumulate data into a large histogram of floats

    - by shoosh
    I'm trying to think of a way to implement the following algorithm using CUDA: Working on a large volume of voxels, for each voxel I calculate an index i and a value c. after the calculation I need to perform histogram[i] += c c is a float value and the histogram can have up to 15,000 bins. I'm looking for a way to implement this efficiently using CUDA. The first obvious problem is that with compute capabilities 1.3 which is what I'm using I can't even do an atomicAdd() of floats so how can I accumulate anything reliably? This example by nVidia does something somewhat simpler. The histograms are saved in the shared memory (which I can't do due to its size) and it only accumulates integers. Can this approach be generalized to my case?

    Read the article

  • WPF DataGridTextColumn Can't type point for float data

    - by Alvin
    I had a WPF DataGrid and use DataGridTextColumn Binding to a Collection. The items in Collection had some float property. When my program launched, I modify the value of float property in DataGrid, if I type a integer value, it works well. But if I type char . for a float value, char . can't be typed. I had to type all the numbers first, and then jump to the . position to type char . to finish my input. So how can I type . in my situation? Thanks.

    Read the article

  • Starting point for learning CAD/CAE file formats?

    - by Escader
    We are developing some stress and strain analysis software at university. Now it's time to move from rectangles and boxes and spheres to some real models. But I still have little idea where to start. In our software we are going to build mesh and then make calculations, but how do I import solid bodies from CAD/CAE software? 1) How CAD/CAE models are organised? How solid bodies are represented? What are the possibilities of DWG, DXF, IGES, STEP formats? There is e.g. a complete DXF reference, but it's too difficult for me to understand without knowing basic concepts. 2) Are there C++ libraries to import solid bodies from CAD/CAE file formats? Won't it be too difficult to build a complete model to be able to import comprehensive file?

    Read the article

  • Algorithm putting point into square with maximal minimum distance

    - by Mikulas Dite
    I'm stuck on this: Have a square. Put n points into this square so the minimal distance (not necessary the average distance) is the highest possible. I'm looking for an algorithm which would be able to generate the coordinates of all points given the count of them. Example results for n=4;5;6: Please don't mention computing-power based stuff such as trying a lot of combination and then nitpicking the right one and similar ideas.

    Read the article

  • AudioQueue recording as float

    - by niklassaers
    Hi guys, I would like to have the result from my recording as a float in the range [0.0, 1.0], alternatively [-1.0, 1.0] because of a bit of math I want to do on it. When I set my recordingformat to be in float, like this: mRecordFormat.mFormatFlags = kLinearPCMFormatFlagIsFloat; I get: Error: AudioQueueNewInput failed ('fmt?') Does this mean the hardware doesn't support recording to floats? If not, how do I set it to record in floats? If so, are there any processor-friendly ways I can convert a signed integer array to a float array? Cheers Nik

    Read the article

  • Communicating with a MW-3170 magnetic card reader

    - by stukelly
    One of our customers has asked if we can interface with a serial magnetic card reader/encoder from a old EPOS system. The device has no make only the MW-3170 model number. Does anybody know how I can communicate with the device? I am currently looking for a programming manual on Google, without much success.

    Read the article

< Previous Page | 29 30 31 32 33 34 35 36 37 38 39 40  | Next Page >