Search Results

Search found 9047 results on 362 pages for 'double math'.

Page 201/362 | < Previous Page | 197 198 199 200 201 202 203 204 205 206 207 208  | Next Page >

  • how do i ininitialize a float to it's max/min value?

    - by Faken
    How do i hard code an absolute maximum or minimum value for a float or double? I want to search out the max/min of an array by simply iterating through and catching the largest. There are also positive and negative infinity for floats, should i use those instead? if so, how do i denote that in my code?

    Read the article

  • C++ random number from a set

    - by user69514
    Is it possible to print a random number in C++ from a set of numbers with ONE SINGLE statement? let's say the set is 2, 5, 22, 55, 332 i looked up rand, but I double it's possible to do in a single statement

    Read the article

  • Deleting Duplicates in MySQL

    - by elmaso
    Query was this: CREATE TABLE `query` ( `id` int(11) NOT NULL auto_increment, `searchquery` varchar(255) NOT NULL default '', `datetime` int(11) NOT NULL default '0', PRIMARY KEY (`id`) ) ENGINE=MyISAM first I want to drop the table with: ALTER TABLE `querynew` DROP `id` and then delete the double entries.. I tried it with: INSERT INTO `querynew` SELECT DISTINCT * FROM `query` but with no success.. :( and with ALTER TABLE query ADD UNIQUE ( searchquery ) - is it possible to save the queries only one time?

    Read the article

  • Performance of looping over an Unboxed array in Haskell

    - by Joey Adams
    First of all, it's great. However, I came across a situation where my benchmarks turned up weird results. I am new to Haskell, and this is first time I've gotten my hands dirty with mutable arrays and Monads. The code below is based on this example. I wrote a generic monadic for function that takes numbers and a step function rather than a range (like forM_ does). I compared using my generic for function (Loop A) against embedding an equivalent recursive function (Loop B). Having Loop A is noticeably faster than having Loop B. Weirder, having both Loop A and B together is faster than having Loop B by itself (but slightly slower than Loop A by itself). Some possible explanations I can think of for the discrepancies. Note that these are just guesses: Something I haven't learned yet about how Haskell extracts results from monadic functions. Loop B faults the array in a less cache efficient manner than Loop A. Why? I made a dumb mistake; Loop A and Loop B are actually different. Note that in all 3 cases of having either or both Loop A and Loop B, the program produces the same output. Here is the code. I tested it with ghc -O2 for.hs using GHC version 6.10.4 . import Control.Monad import Control.Monad.ST import Data.Array.IArray import Data.Array.MArray import Data.Array.ST import Data.Array.Unboxed for :: (Num a, Ord a, Monad m) => a -> a -> (a -> a) -> (a -> m b) -> m () for start end step f = loop start where loop i | i <= end = do f i loop (step i) | otherwise = return () primesToNA :: Int -> UArray Int Bool primesToNA n = runSTUArray $ do a <- newArray (2,n) True :: ST s (STUArray s Int Bool) let sr = floor . (sqrt::Double->Double) . fromIntegral $ n+1 -- Loop A for 4 n (+ 2) $ \j -> writeArray a j False -- Loop B let f i | i <= n = do writeArray a i False f (i+2) | otherwise = return () in f 4 forM_ [3,5..sr] $ \i -> do si <- readArray a i when si $ forM_ [i*i,i*i+i+i..n] $ \j -> writeArray a j False return a primesTo :: Int -> [Int] primesTo n = [i | (i,p) <- assocs . primesToNA $ n, p] main = print $ primesTo 30000000

    Read the article

  • Bound DataGridView not updating data source

    - by Max Yaffe
    I'm trying to bind a table of structures to a DataGridView. Loading and viewing the table is working fine but I can't edit a value and get it stored back into the table. Here's what I'm doing. I have a "primitive" data type, Real defined by public struct MyReal:IMyPrimative { public Double m_Real; //... public MyReal(String val) { m_Real = default(Double); Init(val); } //... } It gets used in a structure: public struct MyReal_Record : IMyRecord { public MyReal Freq { get; set;} MyReal_Record(String[] vals) { Init(vals); } } And the structure is used to define a table using a generic Binding List public class MyTable<S> : BindingList<S> where S: struct, IMyRecord { public Type typeofS; public MyTable() { typeofS = typeof(S); // ... } This table is used as a binding source for a grid, dynamically. private void miLoadFile_Click(object sender, EventArgs e) { MyModel.Table<Real_Record> RTable = new MyModel.Table<Real_Record>(); //... Table initialized here //set up grid with virtual mode dataGridView1.DataSource = RTable; } All of this works fine and I can create RTable, initialize it and display it in a grid. The grid allows editing and has events set for CellParsing and CellFormatting which look like: private void dataGridView1_CellFormatting(object sender, DataGridViewCellFormattingEventArgs e) { if (e.DesiredType != typeof(String)) return; e.Value = e.Value.ToString(); } private void dataGridView1_CellParsing(object sender, DataGridViewCellParsingEventArgs e) { if (e.DesiredType != typeof(MyReal)) return; e.Value = new MyReal(e.Value.ToString()); e.ParsingApplied = true; this.dataGridView1.UpdateCellValue(e.ColumnIndex, e.RowIndex); } When I edit a value in a cell, I can change the text. On leaving the cell, CellParsing fires and the event handler is called. Everything seems to be correct going into the CellParsing handler. e.DesiredType is MyReal. e.Value is a string with the new value. After the new MyReal is created from the string, e.Value is set correctly. RowIndex and ColumnIndex are correct. ReadOnly is set false. However, when I leave the cell, the system restores the original value to the cell. I thought the UpdateCellValue would replace the value in the dataSource but I seem to be missing something. What did I miss? Thanks, Max

    Read the article

  • SDL Video Init causes Exception on Mac OS X 10.8

    - by ScrollerBlaster
    I have just ported my C++ game to OS X and the first time it ran I get the following exception when trying to call SDL_SetVideoMode. 2012-09-28 15:01:05.437 SCRAsteroids[28595:707] * Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Error (1000) creating CGSWindow on line 259' * First throw call stack: ( 0 CoreFoundation 0x00007fff8b53b716 __exceptionPreprocess + 198 1 libobjc.A.dylib 0x00007fff90e30470 objc_exception_throw + 43 2 CoreFoundation 0x00007fff8b53b4ec +[NSException raise:format:] + 204 3 AppKit 0x00007fff8a26a579 _NSCreateWindowWithOpaqueShape2 + 655 4 AppKit 0x00007fff8a268d70 -[NSWindow _commonAwake] + 2002 5 AppKit 0x00007fff8a2277e2 -[NSWindow _commonInitFrame:styleMask:backing:defer:] + 1763 6 AppKit 0x00007fff8a22692f -[NSWindow _initContent:styleMask:backing:defer:contentView:] + 1568 7 AppKit 0x00007fff8a2262ff -[NSWindow initWithContentRect:styleMask:backing:defer:] + 45 8 libSDL-1.2.0.dylib 0x0000000107c228f6 -[SDL_QuartzWindow initWithContentRect:styleMask:backing:defer:] + 294 9 libSDL-1.2.0.dylib 0x0000000107c20505 QZ_SetVideoMode + 2837 10 libSDL-1.2.0.dylib 0x0000000107c17af5 SDL_SetVideoMode + 917 11 SCRAsteroids 0x0000000107be60fb _ZN11SDLGraphics4initEP6IWorldii + 291 ) libc++abi.dylib: terminate called throwing an exception Abort trap: 6 My init code looks like this: if (SDL_Init(SDL_INIT_EVERYTHING) < 0) return false; const SDL_VideoInfo *videoInfo = SDL_GetVideoInfo(); if (!videoInfo) { fprintf(stderr, "Video query failed: %s\n", SDL_GetError()); return false; } /* the flags to pass to SDL_SetVideoMode */ videoFlags = SDL_OPENGL; /* Enable OpenGL in SDL */ videoFlags |= SDL_GL_DOUBLEBUFFER; /* Enable double buffering */ videoFlags |= SDL_HWPALETTE; /* Store the palette in hardware */ /* This checks to see if surfaces can be stored in memory */ if (videoInfo->hw_available) videoFlags |= SDL_HWSURFACE; else videoFlags |= SDL_SWSURFACE; if (w == 0) { widthViewport = videoInfo->current_w; heightViewport = videoInfo->current_h; cout << "Will use full screen resolution of "; videoFlags |= SDL_FULLSCREEN; } else { cout << "Will use full user supplied resolution of "; widthViewport = w; heightViewport = h; videoFlags |= SDL_RESIZABLE; /* Enable window resizing */ } cout << widthViewport << "x" << heightViewport << "\n"; /* This checks if hardware blits can be done */ if (videoInfo->blit_hw) videoFlags |= SDL_HWACCEL; /* Sets up OpenGL double buffering */ SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1); /* get a SDL surface */ surface = SDL_SetVideoMode(widthViewport, heightViewport, SCREEN_BPP, videoFlags); It gets into that last SDL call and throws the exception above. I have tried it in both full screen and resizable window mode, same thing. I build my app old school, on the command line, as opposed to using Xcode.

    Read the article

  • finding "distance" between two pixel's colors.

    - by igor
    Once more something relatively simple, but confused as to what they want. the method to find distance on cartesian coordinate system is distance=sqrt[(x2-x1)^2 + (y2-y1)^2] but how do i apply it here? //Requires: testColor to be a valid Color //Effects: returns the "distance" between the current Pixel's color and // the passed color // uses the standard method to calculate "distance" // uses the same formula as finding distance on a // Cartesian coordinate system double colorDistance(Color testColor) const;

    Read the article

  • Generating JSON request manually, returned HTML causing issues.

    - by mrblah
    Hi, I am generating my JSON manually, and I even escaped for quotes with a preceding backslash. It is causing me problems. My HTML returned looks something like: <div class="blah"><div class="a2">This is just a test! I hope this work's man!</div></div> string json = "MY HTML HERE"; json = json.Replace(@"""", @"\"""); Is there more to replace than just the double quotes?

    Read the article

  • Disable button after submit

    - by Chris Philpotts
    I'm trying to disable a button when a user submits a payment form and the code to post the form is causing a double post in firefox. This problem does not occur when the code is removed, and does not occur in any browser other than firefox. Any idea how to prevent the double post here? System.Text.StringBuilder sb = new StringBuilder(); sb.Append("if (typeof(Page_ClientValidate) == 'function') { "); sb.Append("if (Page_ClientValidate() == false) { return false; }} "); sb.Append("this.value = 'Please wait...';"); sb.Append("this.disabled = true;"); sb.Append(Page.GetPostBackEventReference(btnSubmit )); sb.Append(";"); btnSubmit.Attributes.Add("onclick", sb.ToString()); it's the sb.Append(Page.GetPostBackEventReference(btnSubmit )) line that's causing the issue Thanks EDIT: Here's the c# of the button: <asp:Button ID="cmdSubmit" runat="server" Text="Submit" /> here's the html This code posts twice (and disables the submit button and verifies input): <input type="submit" name="ctl00$MainContent$cmdSubmit" value="Submit" onclick="if (typeof(Page_ClientValidate) == 'function') { if (Page_ClientValidate() == false) { return false; }} this.value = 'Please wait...';this.disabled = true;document.getElementById('ctl00_MainContent_cmdBack').disabled = true;__doPostBack('ctl00$MainContent$cmdSubmit','');" id="ctl00_MainContent_cmdSubmit" /> This code posts twice (but doesn’t disable the submit button): <input type="submit" name="ctl00$MainContent$cmdSubmit" value="Submit" onclick="__doPostBack('ctl00$MainContent$cmdSubmit','');" id="ctl00_MainContent_cmdSubmit" /> This code posts once (but doesn’t verify the user input and doesn’t disable the submit button): <input type="submit" name="ctl00$MainContent$cmdSubmit" value="Submit" id="ctl00_MainContent_cmdSubmit" /> This code posts once (but doesn’t disable submit button): <input type="submit" name="ctl00$MainContent$cmdSubmit" value="Submit" onclick="javascript:WebForm_DoPostBackWithOptions(new WebForm_PostBackOptions(&quot;ctl00$MainContent$cmdSubmit&quot;, &quot;&quot;, true, &quot;&quot;, &quot;&quot;, false, false))" id="ctl00_MainContent_cmdSubmit" /> This code doesn’t post at all: <input type="submit" name="ctl00$MainContent$cmdSubmit" value="Submit" onclick="this.disabled = true;WebForm_DoPostBackWithOptions(new WebForm_PostBackOptions(&quot;ctl00$MainContent$cmdSubmit&quot;, &quot;&quot;, true, &quot;&quot;, &quot;&quot;, false, false))" id="ctl00_MainContent_cmdSubmit" /> Obviously it’s the disabling of the submit button that’s posing the problem. Do you have any ideas how we can disable the submit to avoid multiple clicking?

    Read the article

  • Same data being returned by linq for 2 different executions of a stored procedure?

    - by Paul
    Hello I have a stored procedure that I am calling through Entity Framework. The stored procedure has 2 date parameters. I supply different argument in the 2 times I call the stored procedure. I have verified using SQL Profiler that the stored procedure is being called correctly and returning the correct results. When I call my method the second time with different arguments, even though the stored procedure is bringing back the correct results, the table created contains the same data as the first time I called it. dtStart = 01/08/2009 dtEnd = 31/08/2009 public List<dataRecord> GetData(DateTime dtStart, DateTime dtEnd) { var tbl = from t in db.SP(dtStart, dtEnd) select t; return tbl.ToList(); } GetData((new DateTime(2009, 8, 1), new DateTime(2009, 8, 31)) // tbl.field1 value = 45450 - CORRECT GetData(new DateTime(2009, 7, 1), new DateTime(2009, 7, 31)) // tbl.field1 value = 45450 - WRONG 27456 expected Is this a case of Entity Framework being clever and caching? I can't see why it would cache this though as it has executed the stored procedure twice. Do I have to do something to close tbl? using Visual Studio 2008 + Entity Framework. I also get the message "query cannot be enumerated more than once" a few times every now and then, am not sure if that is relevant? FULL CODE LISTING namespace ProfileDataService { public partial class DataService { public static List<MeterTotalConsumpRecord> GetTotalAllTimesConsumption(DateTime dtStart, DateTime dtEnd, EUtilityGroup ug, int nMeterSelectionType, int nCustomerID, int nUserID, string strSelection, bool bClosedLocations, bool bDisposedLocations) { dbChildDataContext db = DBManager.ChildDataConext(nCustomerID); var tbl = from t in db.GetTotalConsumptionByMeter(dtStart, dtEnd, (int) ug, nMeterSelectionType, nCustomerID, nUserID, strSelection, bClosedLocations, bDisposedLocations, 1) select t; return tbl.ToList(); } } } /// CALLER List<MeterTotalConsumpRecord> _P1Totals; List<MeterTotalConsumpRecord> _P2Totals; public void LoadData(int nUserID, int nCustomerID, ELocationSelectionMethod locationSelectionMethod, string strLocations, bool bIncludeClosedLocations, bool bIncludeDisposedLocations, DateTime dtStart, DateTime dtEnd, ReportsBusinessLogic.Lists.EPeriodType durMainPeriodType, ReportsBusinessLogic.Lists.EPeriodType durCompareToPeriodType, ReportsBusinessLogic.Lists.EIncreaseReportType rptType, bool bIncludeDecreases) { ///Code for setting properties using parameters.. _P2Totals = ProfileDataService.DataService.GetTotalAllTimesConsumption(_P2StartDate, _P2EndDate, EUtilityGroup.Electricity, 1, nCustomerID, nUserID, strLocations, bIncludeClosedLocations, bIncludeDisposedLocations); _P1Totals = ProfileDataService.DataService.GetTotalAllTimesConsumption(_StartDate, _EndDate, EUtilityGroup.Electricity, 1, nCustomerID, nUserID, strLocations, bIncludeClosedLocations, bIncludeDisposedLocations); PopulateLines() //This fills up a list of objects with information for my report ready for the totals to be added PopulateTotals(_P1Totals, 1); PopulateTotals(_P2Totals, 2); } void PopulateTotals(List<MeterTotalConsumpRecord> objTotals, int nPeriod) { MeterTotalConsumpRecord objMeterConsumption = null; foreach (IncreaseReportDataRecord objLine in _Lines) { objMeterConsumption = objTotals.Find(delegate(MeterTotalConsumpRecord t) { return t.MeterID == objLine.MeterID; }); if (objMeterConsumption != null) { if (nPeriod == 1) { objLine.P1Consumption = (double)objMeterConsumption.Consumption; } else { objLine.P2Consumption = (double)objMeterConsumption.Consumption; } objMeterConsumption = null; } } } }

    Read the article

  • Converting a certain SQL query into relational algebra

    - by Fumler
    Just doing an assignment for my database course and I just want to double check that I've correctly wrapped my head around relational algebra. The SQL query: SELECT dato, SUM(pris*antall) AS total FROM produkt, ordre WHERE ordre.varenr = produkt.varenr GROUP BY dato HAVING total >= 10000 The relational algebra: stotal >= 10000( ?R(dato, total)( sordre.varenr = produkt.varenr( datoISUM(pris*antall(produkt x ordre)))) Is this the correct way of doing it?

    Read the article

  • union marshalling issue in C#

    - by senthil
    I have union inside structure and the structure looks like struct tDeviceProperty { DWORD Tag; DWORD Size; union _DP value; }; typedef union _DP { short int i; LONG l; ULONG ul; float flt; double dbl; BOOL b; double at; FILETIME ft; LPSTR lpszA; LPWSTR lpszW; LARGE_INTEGER li; struct tBinary bin; BYTE reserved[40]; } __UDP; struct tBinary { ULONG size; BYTE * bin; }; from the tBinary structure bin has to be converted to tImage (structure is given below) struct tImage { DWORD x; DWORD y; DWORD z; DWORD Resolution; DWORD type; DWORD ID; diccid_t SourceID; const void *buffer; const char *Info; const char *UserImageID; }; to use the same in c# I have done marshaling but not giving proper values when converting the pointer to structure. The C# code is follows, tBinary tBin = new tBinary(); IntPtr tBinbuffer = Marshal.AllocCoTaskMem(Marshal.SizeOf(tBin)); Marshal.StructureToPtr(tBin.bin, tBinbuffer, false); tDeviceProperty tDevice = new tDeviceProperty(); tDevice.bin = tBinbuffer; IntPtr tDevicebuffer = Marshal.AllocCoTaskMem(Marshal.SizeOf(tDevice)); Marshal.StructureToPtr(tDevice.bin, tDevicebuffer, false); Battary tbatt = new Battary(); tbatt.value = tDevicebuffer; IntPtr tbattbuffer = Marshal.AllocCoTaskMem(Marshal.SizeOf(tbatt)); Marshal.StructureToPtr(tbatt.value, tbattbuffer, false); result = GetDeviceProperty(ref tbattbuffer); Battary v = (Battary)Marshal.PtrToStructure(tbattbuffer, typeof(Battary)); tDeviceProperty v2 = (tDeviceProperty)Marshal.PtrToStructure(tDevicebuffer, typeof(tDeviceProperty)); tBinary v3 = (tBinary)Marshal.PtrToStructure(tBinbuffer, typeof(tBinary));

    Read the article

  • Sum up values in an array list in java

    - by user1449997
    Hello to all tired and frustrated programmers, There is a problem I can't solve: In my array list there are Object arrays with the length of three and always on the last cell of the array there is a double. I need a loop which goes through the array list and sums up all doubles. (I need also some other thing from the arrays so a general idea how to loop through an array list would be perfect :-)) Any ideas? Thanks for your help, Greetings Demian

    Read the article

  • Should I add try/catch around when casting on an attribute of JSP implicit object?

    - by Michael Mao
    Hi all: Basically what I mean is like this: List<String[]> routes = (List<String[]>)application.getAttribute("routes"); For the above code, it tries to get an attribute named "routes" from the JSP implicit object - application. But as everyone knows, after this line of code, routes may very well contains a null - which means this application hasn't got an attribute named "routes". Is this "casting on null" good programming practice in Java or not? Basically I try to avoid exceptions such as java.io.InvalidCastException I reckon things like this are more as "heritage" of Java 1.4 when generic types were not introduced to this language. So I guess everything stored in application attributes as Objects (Similar to traditional ArrayList). And when you do "downcast", there might be invalid casts. What would you do in this case? Update: Just found that although in the implicit object application I did store a List of String arrays, when I do this : List<double[]> routes = (List<double[]>)application.getAttribute("routes"); It doesn't produce any error... And I felt not comfortable already... And even with this code: out.print(routes.get(0)); It does print out something strange : [Ljava.lang.String;@18b352f Am I printing a "pointer to String"? I can finally get an exception like this: out.print(routes.get(0)[1]); with error : java.lang.ClassCastException: [Ljava.lang.String; Because it was me to add the application attribute, I know which type should it be cast to. I feel this is not "good enough", what if I forget the exact type? I know there are still some cases where this sort of thing would happen, such as in JSP/Servlet when you do casting on session attributes. Is there a better way to do this? Before you say:"OMG, why you don't use Servlets???", I should justify my reason as this: - because my uni sucks, its server can only work with Servlets generated by JSP, and I don't really want to learn how to fix issues like that. look at my previous question on this , and this is uni homework, so I've got no other choice, forget all about war, WEB-INF,etc, but "code everything directly into JSP" - because the professors do that too. :)

    Read the article

  • Bad_alloc exception when using new for a struct c++

    - by bsg
    Hi, I am writing a query processor which allocates large amounts of memory and tries to find matching documents. Whenever I find a match, I create a structure to hold two variables describing the document and add it to a priority queue. Since there is no way of knowing how many times I will do this, I tried creating my structs dynamically using new. When I pop a struct off the priority queue, the queue (STL priority queue implementation) is supposed to call the object's destructor. My struct code has no destructor, so I assume a default destructor is called in that case. However, the very first time that I try to create a DOC struct, I get the following error: Unhandled exception at 0x7c812afb in QueryProcessor.exe: Microsoft C++ exception: std::bad_alloc at memory location 0x0012f5dc.. I don't understand what's happening - have I used up so much memory that the heap is full? It doesn't seem likely. And it's not as if I've even used that pointer before. So: first of all, what am I doing that's causing the error, and secondly, will the following code work more than once? Do I need to have a separate pointer for each struct created, or can I re-use the same temporary pointer and assume that the queue will keep a pointer to each struct? Here is my code: struct DOC{ int docid; double rank; public: DOC() { docid = 0; rank = 0.0; } DOC(int num, double ranking) { docid = num; rank = ranking; } bool operator>( const DOC & d ) const { return rank > d.rank; } bool operator<( const DOC & d ) const { return rank < d.rank; } }; //a lot of processing goes on here; when a matching document is found, I do this: rank = calculateRanking(table, num); //if the heap is not full, create a DOC struct with the docid and rank and add it to the heap if(q.size() < 20) { doc = new DOC(num, rank); q.push(*doc); doc = NULL; } //if the heap is full, but the new rank is greater than the //smallest element in the min heap, remove the current smallest element //and add the new one to the heap else if(rank > q.top().rank) { q.pop(); cout << "pushing doc on to queue" << endl; doc = new DOC(num, rank); q.push(*doc); } Thank you very much, bsg.

    Read the article

  • how do I initialize a float to its max/min value?

    - by Faken
    How do I hard code an absolute maximum or minimum value for a float or double? I want to search out the max/min of an array by simply iterating through and catching the largest. There are also positive and negative infinity for floats, should I use those instead? If so, how do I denote that in my code?

    Read the article

< Previous Page | 197 198 199 200 201 202 203 204 205 206 207 208  | Next Page >