Search Results

Search found 15630 results on 626 pages for 'variable variables'.

Page 496/626 | < Previous Page | 492 493 494 495 496 497 498 499 500 501 502 503  | Next Page >

• How do you refactor a large messy codebase?

  - by Ricket

  I have a big mess of code. Admittedly, I wrote it myself - a year ago. It's not well commented but it's not very complicated either, so I can understand it -- just not well enough to know where to start as far as refactoring it. I violated every rule that I have read about over the past year. There are classes with multiple responsibilities, there are indirect accesses (I forget the technical term - something like foo.bar.doSomething()), and like I said it is not well commented. On top of that, it's the beginnings of a game, so the graphics is coupled with the data, or the places where I tried to decouple graphics and data, I made the data public in order for the graphics to be able to access the data it needs... It's a huge mess! Where do I start? How would you start on something like this? My current approach is to take variables and switch them to private and then refactor the pieces that break, but that doesn't seem to be enough. Please suggest other strategies for wading through this mess and turning it into something clean so that I can continue where I left off!

  Read the article

• Popup window size in android

  - by Bostjan

  I'm creating a popup window in a listactivity in the event onListItemClick. LayoutInflater inflater = (LayoutInflater) this.getSystemService(Context.LAYOUT_INFLATER_SERVICE); View pop = inflater.inflate(R.layout.popupcontact, null, false); ImageView atnot = (ImageView)pop.findViewById(R.id.aNot); height = pop.getMeasuredHeight(); width = pop.getMeasuredWidth(); Log.e("pw","height: "+String.valueOf(height)+", width: "+String.valueOf(width)); atnot.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { pw.dismiss(); } }); pw = new PopupWindow(pop, width, height, true); // The code below assumes that the root container has an id called 'main' //pw.showAtLocation(v, Gravity.CENTER, 0, 0); pw.showAsDropDown(v, 10, 5); Now, the height and width variables were supposed to be height and width of the layout used for the popup window (popupcontact). But they return 0. I guess that is because the layout isn't rendered yet. Does anyone have a clue, how can I control the size of the popup window without needing to use absolute pixel numbers?

  Read the article

• What's the best way to resolve this scope problem?

  - by Peter Stewart

  I'm writing a program in python that uses genetic techniques to optimize expressions. Constructing and evaluating the expression tree is the time consumer as it can happen billions of times per run. So I thought I'd learn enough c++ to write it and then incorporate it in python using cython or ctypes. I've done some searching on stackoverflow and learned a lot. This code compiles, but leaves the pointers dangling. I tried 'this_node = new Node(...' . It didn't seem to work. And I'm not at all sure how I'd delete all the references as there would be hundreds. I'd like to use variables that stay in scope, but maybe that's not the c++ way. What is the c++ way? class Node { public: char *cargo; int depth; Node *left; Node *right; } Node make_tree(int depth) { depth--; if(depth <= 0) { Node tthis_node("value",depth,NULL,NULL); return tthis_node; } else { Node this_node("operator" depth, &make_tree(depth), &make_tree(depth)); return this_node; } };

  Read the article

• Multiple ajax request and progress bar

  - by hunt

  Hi, In a following piece of code i am create a progress bar and showing its progress as the ajax request get processed. i am faking the progress shown here just by adding 5 in to cnt counter variable after that i made a check when counter reach to 90. at this point if the request is not executed successfully then i will pause/disable the progress bar and whenever response come i will complete the whole progress bar with 100. now the problem is i want to add multiple progress bar as i am firing multiple ajax request. so following is the code to implement only for one request and one progress bar but i want it for more than one. as global variables are used over here for checking response and timer id so i don't know how well i can handle it for multiple request var cnt=0; var res=null; function getProgress(data){ res=data; } var i =0; $('#start').click(function(){ i = setInterval(function() { if(res!=null) { clearInterval(i); $("#pb1").progressbar( "option", "value", cnt=cnt+100 ); } var value = $("#pb1").progressbar("option", "value"); if(value >=90 && res==null){ $("#pb1").progressbar("option", "disable"); } else{ $("#pb1").progressbar( "option", "value", cnt=cnt+5 ); } },2500); $.ajax({ url: 'http://localhost/beta/demo.php', success: getProgress }); }); $("#pb1").progressbar({ value: 0 , change: function(event, ui) { if(res!=null) clearInterval(i); } });

  Read the article

• How to create an array of buttons in C++

  - by mangoman13

  Hi, I'm using C++ in VS2005 and have an 8x8 grid of buttons on a form. I want to have these buttons in an array, so when I click on any of them it will open the same event handler (I think that is what they are called), but I will know the index of which one was clicked on. I know how to do this in VB and C#, but I can't seem to figure it out with C++ Right now I have all my buttons labelled by their location, i.e. b00, b10, b21, etc. So I think what I am looking for is a way to do something like this: Button b[8][8]; //this causes me errors (error C2728: 'System::Windows::Forms::Button' : a native array cannot contain this managed type) and (error C2227: left of '->{ctor}' must point to class/struct/union/generic type) void Assignment(){ b[0][0] = b00; b[1][0] = b10; ... } and then in form1.h: private: System::Void b_Click(System::Object^ sender, System::EventArgs^ e) { //somehow read the coordinates into variables x and y //do something based on these values } Any help would be appreciated. Also let me know if I am going in the complete wrong direction with this. Thanks!

  Read the article

• When NOT TO USE 'this' keyword?

  - by LifeH2O

  Sorry for asking it again, there are already 3 questions about this keyword. But all of them tell the purpose of 'this'. My question is when not to use 'this' keyword . OR Is it all right to use this keyword always in situation like the code class RssReader { private XmlTextReader _rssReader; private XmlDocument _rssDoc; private XmlNodeList _xn; protected XmlNodeList Item { get { return _xn; } } public int Count { get { return _count; } } public bool FetchFeed(String url) { this._rssReader = new XmlTextReader(url); this._rssDoc = new XmlDocument(); _rssDoc.Load(_rssReader); _xn = _rssDoc.SelectNodes("/rss/channel/item"); _count = _xn.Count; return true; } } here i have not used 'this' with "_xn" and "_count" also not with "_rssDoc.Load(_rssReader);" is it fine? Should i use "this" with all occurrences of class variables within the class?

  Read the article

• Effective Method to Manage and Search Through 100,000+ Objects Instantly? (C#)

  - by Kirk

  I'm writing a media player for enthusiasts with large collections (over 100,000 tracks) and one of my main goals is speed in search. I would like to allow the user to perform a Google-esque search of their entire music collection based on these factors: Song Path and File Name Items in ID3 Tag (Title, Artist, Album, etc.) Lyrics What is the best way for me to store this data and search through it? Currently I am storing each track in an object and iterating over an array of these objects checking each of their variables for string matches based on given search text. I've run into problems though where my search is not effective because it is always a phrase search and I'm not sure how to make it more fuzzy. Would an internal DB like SQLlite be faster than this? Any ideas on how I should structure this system? I also need playlist persistence, so that when they close the app and open the app their same playlist loads immediately. How should I store the playlist information so it can load quickly when the application starts? Currently I am JSON encoding the entire playlist, storing it in a text file, and reading it into the ListView at runtime, but it is getting sluggish over 20,000 tracks. Thanks!

  Read the article

• ArrayList<String> NullPointerException

  - by Carlucho

  Am trying to solve a labyrinth by DFS, using adj List to represent the vertices and edges of the graph. In total there are 12 nodes (3 rows[A,B,C] * 4 cols[0,..,3]). My program starts by saving all the vertex labels (A0,..C3), so far so good, then checks the adjacent nodes, also no problems, if movement is possible, it proceeds to create the edge, here its where al goes wrong. adjList[i].add(vList[j].label); I used the debugger and found that vList[j].label is not null it contains a correct string (ie. "B1"). The only variables which show null are in adjList[i], which leads me to believe i have implemented it wrongly. this is how i did it. public class GraphList { private ArrayList<String>[] adjList; ... public GraphList(int vertexcount) { adjList = (ArrayList<String>[]) new ArrayList[vertexCount]; ... } ... public void addEdge(int i, int j) { adjList[i].add(vList[j].label); //NULLPOINTEREXCEPTION HERE } ... } I will really appreaciate if anyone can point me on the right track regrading to what its going wrong... Thanks!

  Read the article

• PAYPAL IPN Response Problem

  - by Gorkem Tolan

  I am having a problem with Paypal IPN response. After payment is made by the customer, paypal ipn returns this url www.mywebsite.com?orderid=32&tx=2AC67201DL3533325&st=Pending&amt=2.50&cc=USD&cm=&item_number=32 There are a couple of issues 1- Postback field names are undefined or missing. Thus I can get the INVALID message. I am not sure if my website does not read POST variables. When I looked at IPN history, it shows that each IPN has been sent with the complete url. 2- Payment status keeps coming Pending. Does this issue cause the first issue? Thank you for your responses in advance. Here is the code: Dim strSandbox As String, strLive As String Dim req As HttpWebRequest strSandbox = "http://www.sandbox.paypal.com/cgi-bin/webscr/" strLive = "https://www.paypal.com/cgi-bin/webscr" req = CType(WebRequest.Create(strSandbox), HttpWebRequest) 'Set values for the request back req.Method = "POST" req.ContentType = "application/x-www-form-urlencoded" Dim param() As Byte param = Request.BinaryRead(HttpContext.Current.Request.ContentLength) Dim strRequest As String strRequest = Encoding.ASCII.GetString(param) strRequest = strRequest & "&cmd=_notify-validate" req.ContentLength = strRequest.Length 'Response.Write(strRequest) 'Send the request to PayPal and get the response Dim streamOut As StreamWriter streamOut = New StreamWriter(req.GetRequestStream(), System.Text.Encoding.ASCII) streamOut.Write(strRequest) streamOut.Close() Dim streamIn As StreamReader streamIn = New StreamReader(req.GetResponse().GetResponseStream()) Dim strResponse As String strResponse = streamIn.ReadToEnd() Response.Write(strResponse) streamIn.Close() If (strResponse = "VERIFIED") Then Response.Redirect("thankyou.aspx") ElseIf (strResponse = "INVALID") Then End If

  Read the article

• Py_INCREF/DECREF: When

  - by Izz ad-Din Ruhulessin

  Is one correct in stating the following: If a Python object is created in a C function, but the function doesn't return it, no INCREF is needed, but a DECREF is. [false]If the function does return it, you do need to INCREF, in the function that receives the return value.[/false] When assigning C typed variables as attributes, like double, int etc., to the Python object, no INCREF or DECREF is needed. Assigning Python objects as attributes to your other Python objects goes like this: PyObject *foo; foo = bar // A Python object tmp = self->foo; Py_INCREF(foo); self->foo = foo; Py_XDECREF(tmp); //taken from the manual, but it is unclear if this works in every situation EDIT: -- can I safely use this in every situation? (haven't run into one where it caused me problems) dealloc of a Python object needs to DECREF for every other Python object that it has as an attribute, but not for attributes that are C types. Edit With 'C type as an attribute I mean bar and baz: typedef struct { PyObject_HEAD PyObject *foo; int bar; double baz; } FooBarBaz;

  Read the article

• C++: select argmax over vector of classes w.r.t. arbitrary expression

  - by karpathy

  Hello, I have trouble describing my problem so I'll give an example: I have a class description that has a couple of variables in it, for example: class A{ float a, b, c, d; } Now, I maintain a vector<A> that contains many of these classes. What I need to do very very often is to find the object inside this vector that satisfies that one of it's parameters is maximal w.r.t to the others. i.e code looks something like: int maxi=-1; float maxa=-1000; for(int i=0;i<vec.size();i++){ res= vec[i].a; if(res > maxa) { maxa= res; maxi=i; } } return vec[maxi]; However, sometimes I need to find class with maximal a, sometimes with maximal b, sometimes the class with maximal 0.8*a + 0.2*b, sometimes I want a maximal a*VAR + b, where VAR is some variable that is assigned in front, etc. In other words, I need to evaluate an expression for every class, and take the max. I find myself copy-pasting this everywhere, and only changing the single line that defines res. What makes it even more complicated is that even the name of the vector changes. Sometimes it's vec, sometimes it can be something else. I have many vectors that contain A's. This could be changed if this makes the problem too hard. Is there some nice way to avoid this insanity in C++? What's the neatest way to handle this? Thank you!

  Read the article

• Highlighting correctly in an emacs major mode

  - by Paul Nathan

  Hi, I am developing an emacs major mode for a language (aka mydsl). However, using the techniques on xahlee's site doesn't seem to be working for some reason (possibly older emacs dialect..) The key issues I am fighting with are (1) highlighting comments is not working and (2), the use of regexp-opt lines is not working. I've reviewed the GNU manual and looked over cc-mode and elisp mode... those are significantly more complicated than I need. ;;;Standard # to newline comment ;;;Eventually should also have %% to %% multiline block comments (defun mydsl-comment-dwim (arg) "comment or uncomment" (interactive "*P") (require 'newcomment) (let ((deactivate-mark nil) (comment-start "#") (comment-end "") comment-dwim arg))) (defvar mydsl-events '("reservedword1" "reservedword2")) (defvar mydsl-keywords '("other-keyword" "another-keyword")) ;;Highlight various elements (setq mydsl-hilite '( ; stuff between " ("\"\\.\\*\\?" . font-lock-string-face) ; : , ; { } => @ $ = are all special elements (":\\|,\\|;\\|{\\|}\\|=>\\|@\\|$\\|=" . font-lock-keyword-face) ( ,(regexp-opt mydsl-keywords 'words) . font-lock-builtin-face) ( ,(regexp-opt mydsl-events 'words) . font-lock-constant-face) )) (defvar mydsl-tab-width nil "Width of a tab for MYDSL mode") (define-derived-mode mydsl-mode fundamental-mode "MYDSL mode is a major mode for editing MYDSL files" ;Recommended by manual (kill-all-local-variables) (setq mode-name "MYDSL script") (setq font-lock-defaults '((mydsl-hilite))) (if (null mydsl-tab-width) (setq tab-width mydsl-tab-width) (setq tab-width default-tab-width) ) ;Comment definitions (define-key mydsl-mode-map [remap comment-dwim] 'mydsl-comment-dwim) (modify-syntax-entry ?# "< b" mydsl-mode-syntax-table) (modify-syntax-entry ?\n "> b" mydsl-mode-syntax-table) ;;A gnu-correct program will have some sort of hook call here. ) (provide 'mydsl-mode)

  Read the article

• memcache is not storing data accross requests

  - by morpheous

  I am new to using memcache, so I may be doing something wrong. I have written a wrapper class around memcache. The wrapper class has only static methods, so is a quasi singleton. The class looks something like this: class myCache { private static $memcache = null; private static $initialized = false; public static function init() { if (self::$initialized) return; self::$memcache = new Memcache(); if (self::configure()) //connects to daemon { self::store('foo', 'bar'); } else throw ConnectionError('I barfed'); } public static function store($key, $data, $flag=MEMCACHE_COMPRESSED, $timeout=86400) { if (self::$memcache->get($key)!== false) return self::$memcache->replace($key, $data, $flag, $timeout); return self::$memcache->set($key, $data, $flag, $timeout); } public static function fetch($key) { return self::$memcache->get($key); } } //in my index.php file, I use the class like this require_once('myCache.php'); myCache::init(); echo 'Stored value is: '. myCache::fetch('foo'); The problem is that the myCache::init() method is being executed in full everytime a page is requested. I then remembered that static variables do not maintain state accross page requests. So I decided instead, to store the flag that indicates whether the server contains the start up data (for our purposes, the variable 'foo', with value 'bar') in memcache itself. Once the status flag is stored in memcache itself, It solves the problem of the initialisation data being loaded for every page request (which quite frankly, defeats the purpose of memcache). However, having solved that problem, when I come to fetch the data in memcache, it is empty. I dont understand whats going on. Can anyone clarify how I can store my data once and retrieve it accross page requests? BTW, (just to clarify), the get/set is working correctly, and if I allow memcache to load the initialisation data for each page request, (which is silly), then the data is available in memcache.

  Read the article

• Optimizing a shared buffer in a producer/consumer multithreaded environment

  - by Etan

  I have some project where I have a single producer thread which writes events into a buffer, and an additional single consumer thread which takes events from the buffer. My goal is to optimize this thing for a single machine to achieve maximum throughput. Currently, I am using some simple lock-free ring buffer (lock-free is possible since I have only one consumer and one producer thread and therefore the pointers are only updated by a single thread). #define BUF_SIZE 32768 struct buf_t { volatile int writepos; volatile void * buffer[BUF_SIZE]; volatile int readpos;) }; void produce (buf_t *b, void * e) { int next = (b->writepos+1) % BUF_SIZE; while (b->readpos == next); // queue is full. wait b->buffer[b->writepos] = e; b->writepos = next; } void * consume (buf_t *b) { while (b->readpos == b->writepos); // nothing to consume. wait int next = (b->readpos+1) % BUF_SIZE; void * res = b->buffer[b->readpos]; b->readpos = next; return res; } buf_t *alloc () { buf_t *b = (buf_t *)malloc(sizeof(buf_t)); b->writepos = 0; b->readpos = 0; return b; } However, this implementation is not yet fast enough and should be optimized further. I've tried with different BUF_SIZE values and got some speed-up. Additionaly, I've moved writepos before the buffer and readpos after the buffer to ensure that both variables are on different cache lines which resulted also in some speed. What I need is a speedup of about 400 %. Do you have any ideas how I could achieve this using things like padding etc?

  Read the article

• InvalidCastException when getting Text from a Label referenced by dynamicaly built String, Fix?

  - by Chris

  NET Version: 3.5 Ok, I recieve an error (System.InvalidCastException was unhandled. Message="Unable to cast object of type 'System.Windows.Forms.Control[]' to type 'System.Windows.Forms.Label'.") when trying to get Text from a Label referenced by a dynamicly built string. Here's my situation; I have an array of 250 labels named l1 - l250. What I want to do is loop through them using this while statement: int c = 1; while (c < 251) { string k = "l" + c.ToString(); //dynamic name of Control(Label) object ka = Controls.Find(k, true); string ct = ((Label)ka).Text; //<<Error Occurs Here build = build + ct; c++; } and get the text value of each to build a string named build. I don't get any build errors, just this while debuging. While debuging I can go down to view my local variables. When looking through these, I can view the contents of object ka; it does contain the correct Text value of the correct Label I want to "access". I just don't understand how to get there. The text value is listed under "[0]" which is the only subcatagory for "ka".

  Read the article

• Using same onmouseover function for multiple objects

  - by phpscriptcoder

  I'm creating a building game in JavaScript and PHP that involves a grid. Each square in the grid is a div, with an own onmouseover and onmousedown function: for(x=0; x < width; x++) { for(y=0; y < height; y++) { var div = document.createElement("div"); //... div.onmouseclick = function() {blockClick(x, y)} div.onmouseover = function() {blockMouseover(x, y)} game.appendChild(div); } } But, all of the squares seem to have the x and y of the last square that was added. I can sort of see why this is happening - it is making a pointer to x and y instead of cloning the variables - but how could I fix it? I even tried for(x=0; x < width; x++) { for(y=0; y < height; y++) { var div = document.createElement("div"); var myX = x; var myY = y; div.onmouseclick = function() {blockClick(myX, myY)} div.onmouseover = function() {blockMouseover(myX, myY)} game.appendChild(div); } } with the same result. I was using div.setAttribute("onmouseover", ...) which worked in Firefox, but not IE. Thanks!

  Read the article

• Passing in a lambda to a Where statement

  - by sonicblis

  I noticed today that if I do this: var items = context.items.Where(i => i.Property < 2); items = items.Where(i => i.Property > 4); Once I access the items var, it executes only the first line as the data call and then does the second call in memory. However, if I do this: var items = context.items.Where(i => i.Property < 2).Where(i => i.Property > 4); I get only one expression executed against the context that includes both where statements. I have a host of variables that I want to use to build the expression for the linq lambda, but their presence or absence changes the expression such that I'd have to have a rediculous number of conditionals to satisfy all cases. I thought I could just add the Where() statements as in my first example above, but that doesn't end up in a single expression that contains all of the criteria. Therefore, I'm trying to create just the lambda itself as such: //bogus syntax if (var1 == "something") var expression = Expression<Func<item, bool>>(i => i.Property == "Something); if (var2 == "somethingElse") expression = expression.Where(i => i.Property2 == "SomethingElse"); And then pass that in to the where of my context.Items to evaluate. A) is this right, and B) if so, how do you do it?

  Read the article

• Wrappers of primitive types in arraylist vs arrays

  - by ismail marmoush

  Hi, In "Core java 1" I've read CAUTION: An ArrayList is far less efficient than an int[] array because each value is separately wrapped inside an object. You would only want to use this construct for small collections when programmer convenience is more important than efficiency. But in my software I've already used Arraylist instead of normal arrays due to some requirements, though "The software is supposed to have high performance and after I've read the quoted text I started to panic!" one thing I can change is changing double variables to Double so as to prevent auto boxing and I don't know if that is worth it or not, in next sample algorithm public void multiply(final double val) { final int rows = getSize1(); final int cols = getSize2(); for (int i = 0; i < rows; i++) { for (int j = 0; j < cols; j++) { this.get(i).set(j, this.get(i).get(j) * val); } } } My question is does changing double to Double makes a difference ? or that's a micro optimizing that won't affect anything ? keep in mind I might be using large matrices.2nd Should I consider redesigning the whole program again ?

  Read the article

• ADODB.Connection undefined

  - by Wes Groleau

  Reference http://stackoverflow.com/questions/1690622/excel-vba-to-sql-server-without-ssis After I got the above working, I copied all the global variables/constants from the routine, which included Const CS As String = "Driver={SQL Server};" _ & "Server=**;" _ & "Database=**;" _ & "UID=**;" _ & "PWD=**" Dim DB_Conn As ADODB.Connection Dim Command As ADODB.Command Dim DB_Status As Stringinto a similar module in another spreadsheet. I also copied Sub Connect_To_Lockbox() If DB_Status < "Open" Then Set DB_Conn = New Connection DB_Conn.ConnectionString = CS DB_Conn.Open ' problem! DB_Status = "Open" End If End SubI added the same reference (ADO 2.8) The first spreadsheet still works; the seccond at DB_Conn.Open pops up "Run-time error '-214767259 (80004005)': [Microsoft][ODBC Driver Manager] Data source name not found and no default driver specified" Removing the references on both, saving files, re-opening, re-adding the references doesn't help. The one still works and the other gets the error. ?!?

  Read the article

• zend session exception on zend_session::start with forms

  - by Grant Collins

  Hi I'm having issues with trying to use Zend_Form_SubForm and sessions. My controller is in essance acting a wizard showing different subforms depending on the stage of the wizard. Using the example I am planning on storing the forms in a session namespace. My controller looks like this. include 'mylib/Form/addTaskWizardForm.php'; class AddtaskController extends Zend_Controller_Action{ private $config = null; private $log = null; private $subFormSession = null; /** * This function is called and initialises the global variables to this object * which is the configuration details and the logger to write to the log file. */ public function init(){ $this->config = Zend_Registry::getInstance()->get('config'); $this->log = Zend_Registry::getInstance()->get('log'); //set layout $this->_helper->layout->setLayout('no-sidemenus'); //we need to get the subforms and $wizardForms = new addTaskWizardForm(); $this->subFormSession = new Zend_Session_Namespace('addTaskWizardForms'); if(!isset($this->subFormSession->subforms)){ $this->subFormSession->subforms = $wizardForms; } } /** * The Landing page controller for the site. */ public function indexAction(){ $form = $this->subFormSession->subforms->getSubForm('start'); $this->view->form = $form; } However this is causing the application session to crash out with Uncaught exception 'Zend_Session_Exception' with message 'Zend_Session::start() Any idea why this is having issues with the Zend Session?? thanks.

  Read the article

• FFMEPG permission problem, is there any alternative solution instead of FFMPEG?

  - by caglaror

  We have some kind of permenant permission problem on FFMPEG.exe to write JPEG file on to HDD. We are using IIS and try all permission methods to ffmepg.exe, its including folder,folders, cmd.exe and any executable file, related folder, file. Also we tried many many command examples. But never went beyond the "permission denied" error messages. We give up. Do you know another alternative solution to pick images from flv, f4v movie files? Or %100 quaranteed method to achive this permission control on IIS? Thank you. ---last code we try variables etc. aren't shown here. jpegYapKomutu = videoEditorKlasoru &"\ffmpeg.exe -i " & videoEditorKlasoru & "\deneme.flv" &" -s 480×360 -ss 00:00:"&saniyesi&" -vframes 1 -f mjpeg "& "C:\Webhome\normworks\caglarorhan\deneme.jpg" WScript.Run "%COMSPEC% /C dir" & jpegYapKomutu

  Read the article

• floating point equality in Python and in general

  - by eric.frederich

  I have a piece of code that behaves differently depending on whether I go through a dictionary to get conversion factors or whether I use them directly. The following piece of code will print 1.0 == 1.0 -> False But if you replace factors[units_from] with 10.0 and factors[units_to ] with 1.0 / 2.54 it will print 1.0 == 1.0 -> True #!/usr/bin/env python base = 'cm' factors = { 'cm' : 1.0, 'mm' : 10.0, 'm' : 0.01, 'km' : 1.0e-5, 'in' : 1.0 / 2.54, 'ft' : 1.0 / 2.54 / 12.0, 'yd' : 1.0 / 2.54 / 12.0 / 3.0, 'mile' : 1.0 / 2.54 / 12.0 / 5280, 'lightyear' : 1.0 / 2.54 / 12.0 / 5280 / 5.87849981e12, } # convert 25.4 mm to inches val = 25.4 units_from = 'mm' units_to = 'in' base_value = val / factors[units_from] ret = base_value * factors[units_to ] print ret, '==', 1.0, '->', ret == 1.0 Let me first say that I am pretty sure what is going on here. I have seen it before in C, just never in Python but since Python in implemented in C we're seeing it. I know that floating point numbers will change values going from a CPU register to cache and back. I know that comparing what should be two equal variables will return false if one of them was paged out while the other stayed resident in a register. Questions What is the best way to avoid problems like this?... In Python or in general. Am I doing something completely wrong? Side Note This is obviously part of a stripped down example but what I'm trying to do is come with with classes of length, volume, etc that can compare against other objects of the same class but with different units. Rhetorical Questions If this is a potentially dangerous problem since it makes programs behave in an undetermanistic matter, should compilers warn or error when they detect that you're checking equality of floats Should compilers support an option to replace all float equality checks with a 'close enough' function? Do compilers already do this and I just can't find the information.

  Read the article

• log4net - why would the same MyLog.Debug line not work at one point of startup, but work at another

  - by Greg

  Hi, During startup of my WinForms application I'm noting that there are a couple of points (before the MainForm renders) that do a "MyDataSet.GetInstance()". For the first one the MyLog.Debug line comes through in the VS2008 output window, but for a later one it does work and come through. What could explain this? What settings could I check at debug time to see why an output line for a MyLog.Debug line doesn't come out in the output window? namespace IntranetSync { public class MyDataSet { private static readonly ILog MyLog = LogManager.GetLogger(typeof(MyDataSet)); public static MyDataSet GetInstance() { MyLog.Debug("MyDataSet GetInstance() ====================================="); if (myDataSet == null) { myDataSet = new MyDataSet(); } return myDataSet; } . . . PS. What I have been doing re log4net repository initialization is putting the following line as a private variables in the classes I use logging - is this OK? static class Program { private static readonly ILog MyLog = LogManager.GetLogger(typeof(MainForm)); . . . public class Coordinator { private static readonly ILog MyLog = LogManager.GetLogger(typeof(MainForm)); . . . public class MyDataSet { private static readonly ILog MyLog = LogManager.GetLogger(typeof(MyDataSet)); . . .

  Read the article

• Performance of VIEW vs. SQL statement

  - by Matt W.

  I have a query that goes something like the following: select <field list> from <table list> where <join conditions> and <condition list> and PrimaryKey in (select PrimaryKey from <table list> where <join list> and <condition list>) and PrimaryKey not in (select PrimaryKey from <table list> where <join list> and <condition list>) The sub-select queries both have multiple sub-select queries of their own that I'm not showing so as not to clutter the statement. One of the developers on my team thinks a view would be better. I disagree in that the SQL statement uses variables passed in by the program (based on the user's login Id). Are there any hard and fast rules on when a view should be used vs. using a SQL statement? What kind of performance gain issues are there in running SQL statements on their own against regular tables vs. against views. (Note that all the joins / where conditions are against indexed columns, so that shouldn't be an issue.) EDIT for clarification... Here's the query I'm working with: select obj_id from object where obj_id in( (select distinct(sec_id) from security where sec_type_id = 494 and ( (sec_usergroup_id = 3278 and sec_usergroup_type_id = 230) or (sec_usergroup_id in (select ug_gi_id from user_group where ug_ui_id = 3278) and sec_usergroup_type_id = 231) ) and sec_obj_id in ( select obj_id from object where obj_ot_id in (select of_ot_id from obj_form left outer join obj_type on ot_id = of_ot_id where ot_app_id = 87 and of_id in (select sec_obj_id from security where sec_type_id = 493 and ( (sec_usergroup_id = 3278 and sec_usergroup_type_id = 230) or (sec_usergroup_id in (select ug_gi_id from user_group where ug_ui_id = 3278) and sec_usergroup_type_id = 231) ) ) and of_usage_type_id = 131 ) ) ) ) or (obj_ot_id in (select of_ot_id from obj_form left outer join obj_type on ot_id = of_ot_id where ot_app_id = 87 and of_id in (select sec_obj_id from security where sec_type_id = 493 and ( (sec_usergroup_id = 3278 and sec_usergroup_type_id = 230) or (sec_usergroup_id in (select ug_gi_id from user_group where ug_ui_id = 3278) and sec_usergroup_type_id = 231) ) ) and of_usage_type_id = 131 ) and obj_id not in (select sec_obj_id from security where sec_type_id = 494) )

  Read the article

• Jboss 6 Cluster Singleton Clustered

  - by DanC

  I am trying to set up a Jboss 6 in a clustered environment, and use it to host clustered stateful singleton EJBs. So far we succesfully installed a Singleton EJB within the cluster, where different entrypoints to our application (through a website deployed on each node) point to a single environment on which the EJB is hosted (thus mantaining the state of static variables). We achieved this using the following configuration: Bean interface: @Remote public interface IUniverse { ... } Bean implementation: @Clustered @Stateful public class Universe implements IUniverse { private static Vector<String> messages = new Vector<String>(); ... } jboss-beans.xml configuration: <deployment xmlns="urn:jboss:bean-deployer:2.0"> <!-- This bean is an example of a clustered singleton --> <bean name="Universe" class="Universe"> </bean> <bean name="UniverseController" class="org.jboss.ha.singleton.HASingletonController"> <property name="HAPartition"><inject bean="HAPartition"/></property> <property name="target"><inject bean="Universe"/></property> <property name="targetStartMethod">startSingleton</property> <property name="targetStopMethod">stopSingleton</property> </bean> </deployment> The main problem for this implementation is that, after the master node (the one that contains the state of the singleton EJB) shuts down gracefuly, the Singleton's state is lost and reset to default. Please note that everything was constructed following the JBoss 5 Clustering documents, as no JBoss 6 documents were found on this subject. Any information on how to solve this problem or where to find JBoss 6 documention on clustering is appreciated.

  Read the article

< Previous Page | 492 493 494 495 496 497 498 499 500 501 502 503  | Next Page >