Search Results

Search found 13867 results on 555 pages for 'avoid learning'.

Page 380/555 | < Previous Page | 376 377 378 379 380 381 382 383 384 385 386 387  | Next Page >

• How do polymorphic inline caches work with mutable types?

  - by kingkilr

  A polymorphic inline cache works by caching the actual method by the type of the object, in order to avoid the expensive lookup procedures (usually a hashtable lookup). How does one handle the type comparison if the type objects are mutable (i.e. the method might be monkey patched into something different at run time). The one idea I've come up with would be a "class counter" that gets incremented each time a method is adjusted, however this seems like it would be exceptionally expensive in a heavily monkey patched environ since it would kill all the PICs for that class, even if the methods for them weren't altered. I'm sure there must be a good solution to this, as this issue is directly applicable to Javascript and AFAIK all 3 of the big JS VMs have PICs (wow acronym ahoy).

  Read the article

• List of divisors of an integer n (Haskell)

  - by Code-Guru

  I currently have the following function to get the divisors of an integer: -- All divisors of a number divisors :: Integer -> [Integer] divisors 1 = [1] divisors n = firstHalf ++ secondHalf where firstHalf = filter (divides n) (candidates n) secondHalf = filter (\d -> n `div` d /= d) (map (n `div`) (reverse firstHalf)) candidates n = takeWhile (\d -> d * d <= n) [1..n] I ended up adding the filter to secondHalf because a divisor was repeating when n is a square of a prime number. This seems like a very inefficient way to solve this problem. So I have two questions: How do I measure if this really is a bottle neck in my algorithm? And if it is, how do I go about finding a better way to avoid repetitions when n is a square of a prime?

  Read the article

• Why is my onSharedPreferenceChangeListener being called multiple times when I change a pref.

  - by brockoli

  I've written an app with 3 tabs. Each tab has the same list view with different data sources. I have setup SharedPreferences in the tabhost activity, but I put my onSharedPreferenceChangeListener method in my listactivity. When I change a preference, my listener gets called and it updates my database. This is all working. However, if I change the data in tab 1, it calls my listener once. If I change the data for tab 2 it calls it twice and if I change the data in tab 3 it calls it three times. Any idea why it works this way? I guess I could setup my shared prefs in my listactivity and that might avoid the issue, but I'm curious why my listener is called multiple times if it's in a different tab. brockoli

  Read the article

• How to set the bounce address using System.Net.Mail?

  - by Anthony

  I'm trying to implement the Variable envelope return path (VERP) method to manage email addresses (ie when an email I send bounces back I want it to be sent to a specific email address so that I can update my database to avoid sending emails to that email address in the future). According to this article it is possible to specify the email address a bounce email is sent to. How do you do this in .Net? For example say I ([email protected]) want to send an email to you ([email protected]). If [email protected] doesn't exist anymore I want yourserver to send the bounce email to [email protected]). This way when I receive this bounced email I know that [email protected] is not a valid email address anymore and I can update my database accordingly. In this example, the bounce address would be: [email protected] How do you specify it using System.Net.Mail?

  Read the article

• File Encrypt/Decrypt under load?

  - by chopps

  I found an interesting article about encrypting and decrypting files but since it uses a file.dat to store the key this will run into problems when theres alot of users on the site dealing with alot of files. http://www.codeproject.com/KB/security/VernamEncryption.aspx?display=Print Should a new file be created every time a file needs decrypting or would there be a better way to do this? UPDATE: Here is what im using to avoid the locking problems. using (Mutex FileLock = new Mutex(true, System.Guid.NewGuid().ToString())) { try { FileLock.WaitOne(); using (FileStream fs = new FileStream(keyFile, FileMode.Open)) { keyBytes = new byte[fs.Length]; fs.Read(keyBytes, 0, keyBytes.Length); } } catch (Exception ex) { EventLog.LogEvent(ex); } finally { FileLock.ReleaseMutex(); } } I tested it on 1000 TIFFs doing both encryption and decryption without any errors.

  Read the article

• My C# program running as Windows Service is blocking Windows XP from hibernation

  - by sherpa

  I have Windows Service written in C#. It starts two threads, one is pooling a Web Service, second is waiting on a Monitor object for a new job to arrive. Besides that, the main thread acts as a WCF service host using NetNamedPipeBinding. It lets the client application to register a callback and then sends notifications back. The problem I have is that when this Windows Service is running, I cannot hibernate or Standby my computer which is running on Windows XP, SP3. When I set Windows to hibernate or standby, nothing happens. Then, at the moment when I go to Service Manager and stop the service, the system hibernation starts immediately. The service class extending the ServiceBase has properties like CanHandlePowerEvent, CanPauseAndContinue, etc. set to true... That didn't make any difference. The question is: what can be blocking the Hibernation/Standby from proceeding? What should I take care about to avoid it?

  Read the article

• How to make WPF app work as a child process in Citrix

  - by RichardOD

  I am working on a 3rd party application that allows plugins to be written in .NET 1.1. I have decided I would like to write my plugin in a seperate process that is called from the .NET 1.1 application (achieved using Process.Start). This is fine- I create a new process that is a WPF app. When I launch this through MSTSC everything works as expected, however when I run the app through Citrix, the WPF child app fails to render correctly, and the mouse position starts going crazy- the child process window is basically not usable. Is there a way to avoid this happening? If I create a seperate WPF application and deploy this through Citrix everything works fine. If I create a child Windows forms app in .NET 3.5, that also works fine.

  Read the article

• R- delete rows in multiple columns by unique number

  - by Vincent Moriarty

  Given data like this C1<-c(3,-999.000,4,4,5) C2<-c(3,7,3,4,5) C3<-c(5,4,3,6,-999.000) DF<-data.frame(ID=c("A","B","C","D","E"),C1=C1,C2=C2,C3=C3) How do I go about removing the -999.000 data in all of the columns I know this works per column DF2<-DF[!(DF$C1==-999.000 | DF$C2==-999.000 | DF$C3==-999.000),] But I'd like to avoid referencing each column. I am thinking there is an easy way to reference all of the columns in a particular data frame aka: DF3<-DF[!(DF[,]==-999.000),] or DF3<-DF[!(DF[,(2:4)]==-999.000),] but obviously these do not work And out of curiosity, bonus points if you can me why I need that last comma before the ending square bracket as in: ==-999.000),]

  Read the article

• when is java faster than c++ (or when is JIT faster then precompiled)?

  - by kostja

  I have heard that under certain circumstances, Java programs or rather parts of java programs are able to be executed faster than the "same" code in C++ (or other precompiled code) due to JIT optimizations. This is due to the compiler being able to determine the scope of some variables, avoid some conditionals and pull similar tricks at runtime. Could you give an (or better - some) example, where this applies? And maybe outline the exact conditions under which the compiler is able to optimize the bytecode beyond what is possible with precompiled code? NOTE : This question is not about comparing Java to C++. Its about the possibilities of JIT compiling. Please no flaming. I am also not aware of any duplicates. Please point them out if you are.

  Read the article

• Inline function and calling cost in C

  - by Eonil

  I'm making a vector/matrix library. (GCC, ARM NEON, iPhone) typedef struct{ float v[4]; } Vector; typedef struct{ Vector v[4]; } Matrix; I passed struct data as pointer to avoid performance degrade from data copying when calling function. So I thought designed function like this: void makeTranslation(const Vector* factor, Matrix* restrict result); But, if function is inline, is there any reason to pass values as pointer for performance? Do those variables copied too? How about register and caches? inline Matrix makeTranslation(Vector factor) __attribute__ ((always_inline)); How do you think about calling costs of each cases?

  Read the article

• Creating a unique key based on file content in python

  - by Cawas

  I got many, many files to be uploaded to the server, and I just want a way to avoid duplicates. Thus, generating a unique and small key value from a big string seemed something that a checksum was intended to do, and hashing seemed like the evolution of that. So I was going to use hash md5 to do this. But then I read somewhere that "MD5 are not meant to be unique keys" and I thought that's really weird. What's the right way of doing this? edit: by the way, I took two sources to get to the following, which is how I'm currently doing it and it's working just fine, with Python 2.5: import hashlib def md5_from_file (fileName, block_size=2**14): md5 = hashlib.md5() f = open(fileName) while True: data = f.read(block_size) if not data: break md5.update(data) f.close() return md5.hexdigest()

  Read the article

• Fast parsing of PHP in C#

  - by Jessica Shea

  Hello there, I've got a requirement for parsing PHP files in C#. We essentially require some of the devs in another country to upload PHP files and once uploaded we need to check the php files and get a list of all the methods and classes/functions etc. I thought of using a regex but I can't workout if a function belongs to a class etc, so I was wondering if theres already something 'out there' that will parse out PHP files and spit out its functions (I'm trying to avoid writing a full blow AST implementation). Does anyone have any idea? I looked at Coco/R but I couldn't find a PHP grammar file. I'm using .NET 2.0 and C#.

  Read the article

• C sharp: read last "n" lines of log file

  - by frictionlesspulley

  need a snippet of code which would read out last "n lines" of a log file. I came up with the following code from the net.I am kinda new to C sharp. Since the log file might be quite large, I want to avoid overhead of reading the entire file.Can someone suggest any performance enhancement. I do not really want to read each character and change position. var reader = new StreamReader(filePath, Encoding.ASCII); reader.BaseStream.Seek(0, SeekOrigin.End); var count = 0; while (count <= tailCount) { if (reader.BaseStream.Position <= 0) break; reader.BaseStream.Position--; int c = reader.Read(); if (reader.BaseStream.Position <= 0) break; reader.BaseStream.Position--; if (c == '\n') { ++count; } } var str = reader.ReadToEnd();

  Read the article

• Require Integer Value not Memory Address whilst avoiding Invalid receiver type compiler warning

  - by Dave Anderson

  I have the following code; int days = [[SettingsUtils daysToRetainHistory] intValue]; [retainHistory setText:[NSString stringWithFormat:@"Days to retain History: %d", days]]; [daysToRetainHistory setValue:days animated:NO]; where [SettingsUtils daysToRetainHistory] is as follows; + (int) daysToRetainHistory { return (int)[[NSUserDefaults standardUserDefaults] objectForKey:@"CaseBaseDaysToRetainHistory"]; } I get the compiler warning Invalid receiver type 'int' because I call intValue on an int but unless I do this I can't seem to get the integer value out and always end up with the memory address i.e. 98765432 instead of 9 which ruins the UILabel display [retainHistory] and the UISlider [daysToRetainHistory] value. How do I avoid the compiler warning and still get my integer value in the label and the necessary float value for setting the UISlider value?

  Read the article

• Looking for a real-time IMAP notification of new Emails

  - by Emil

  I'm looking for a way to monitor a GMail inbox for new e-mails. However, I want to avoid checking every few minutes and I'm looking for some sort of real-time notification. I've noticed that Outlook (and other IMAP-supporting clients) instantly show when there is a new e-mail, but unfortunately all .NET IMAP libraries seem to lack this functionality. Does anyone know of an IMAP library that has this functionality? Or is there another way to be instantly notified of new message without doing some short-period polling?

  Read the article

• How to approach local database management via Flex/Air App

  - by Damon

  I am planning on using Flash Builder 4/Flex to write an AIR application which is primarily based around recording, storing and analyzing data. I'll be creating charts etc that need to update in almost real time. It's essential to me that the application be able to function without an internet connection so I need a local database of some variety, but I would also eventually like to build in online synchronization of the data where either database can be update each other based on newer information. Moreover, some type of encryption would definitely be welcome, and speed is a large concern With all that in mind, what is my best approach to try and avoid headaches down the road?

  Read the article

• split html text in 2 paragraphs

  - by Luca Romagnoli

  hi i have a html text like this: aaa dafjsld dslajfk òsal asfòljd <a href="ciao.com">aa aa</a> adsfsadfsadfs i want to split it in 2 paragraphs. but i don't want to generate this situation: <p>aaa dafjsld dslajfk òsal asfòljd <a href="ciao.com">aa</p><p> aa</a> adsfsadfsadfs</p> how can i check if the split involves any tags and avoid it? thanks

  Read the article

• How to use Map element as text of a JComboBox

  - by llm

  I am populating a JComboBox (using addItem()) with all the elements of a collection. Each element in the collection is a HashMap (so its a ComboBox of Hashmaps..). My question is - Given that I need each item to be a HashMap how do I set the text to apear in the combobox on the GUI? It needs to be the value of a certain key in the map. Normally if I am populating a combobox with my own type, I would just overide the toString() method...but I am not sure how to acheive this since I am using a Java HashMap. Any ideas (if possible, without implementing my own HashMap)? Update: It seems like there isn't anyway to avoid having the object int the JComboBox overide toString() if I want custom functionality..I wish there was a way to (1) specify the objects to be loaded into the JComboBox and (2) specify how these objects are to appear in the GUI.

  Read the article

• CSS gurus, can I make my absolutely positioned child element force the main parent's height?

  - by alex

  This is kind of hard to explain. I have an absolutely positioned floating secondary content box. It works great in all occurrences. Except, when you submit a form and don't fill out the fields (see here, and push send). The box expands to show the errors, and underneath the footer there is a blank space. The best example I can give is to see it in action (link above). I've played with min-height and it didn't work too good. I'd also like to avoid expanding the footer with code in the event of form errors if I can help it. Should I ditch the absolute positioning? And try with margins? Is there any other way to get it to work?

  Read the article

• Calling same function until it connect to server

  - by user171523

  I am in the process of designing a system where i need to keep on trying to connect to MQ server unitl i get a connection. By default if the MQ is not availlble it will thorugh exception. How can call the same method again and again until i get the connection. I know i can use recursion, is there any better way to do it . Becuase i would like to avoid infinite loops. I also want to wait the the furthere processing until i get connection. I am using .net 2.0 with C#. It is window Service application.

  Read the article

• Prevent my program from being flagged as malware

  - by user120242

  I know that this kind of behavior should be avoided in a publicly deployed program, but it's necessary. I do some hooking of process creation and file/registry I/O, and unpacking. I still trip a heuristic here and there, and I'm worried about future detections. Could I just contact as many AV vendors as I can, submit my program, and provide a link to my program being served publicly? Would it be possible to convince AV vendors to "whitelist" it? Does anyone perhaps have a list of places to submit false positives? Another problem I have is with people who don't update their malware scanners. There seems to be many people who just have old malware defintions and never bother to update. Is there anything that can be done about this? Or, if not, a way to check older definitions so I can locate what is being tripped, so I can try to avoid using that code?

  Read the article

• What do gurus say about Requirements Traceability Matrix?

  - by Jaywalker

  Our organization is at CMMI Level 2, and as part of the requirements of the level, we have to maintain an RTM which more or less contains the following entries for each requirement: Requirement Description Reference Section Functional Specification Document Reference Section Design Document Reference Section Test Cases Document Now, this might be an overkill for a small project. But more importantly, this could be a nightmare to maintain when the requirements/ features keep changing, and documents have to be constantly updated. What do the gurus say about this? Should one avoid such level of documentation or are there any tools to manage when a "change" out dates so many artifacts? And by using the term 'gurus', I am not talking of coding champs; rather people like Steve McConnel or others who have worked on commercial projects of medium to large scale. Quotes/ book references/ articles will suit me. EDIT: It's not just requirements that change. Design Document can change; well, even test cases may change.

  Read the article

• Limit scope of #define

  - by Ujjwal Singh

  What is the correct strategy to limit the scope of #define and avoid unwarrented token collisions. In the following configuration: Main.c # include "Utility_1.h" # include "Utility_2.h" VOID Utility() // Was written without knowing of: Utility_1 & Utility_2 { const UINT ZERO = 0; } VOID Main() { ... } // Collision; for Line:5 Compiler does not indicate what replaced Utility_1.h # define ZERO "Zero" # define ONE "One" BOOL Utility_1(); Utility_2.h # define ZERO '0' # define ONE '1' BOOL Utility_2(); Utility_2.c # include "Utility_2.h" BOOL Utility_2() { // Using: ZERO & ONE } //Collision: Character Literal replaced with String {Edit} Note: This is supposed to be a generic quesition so do not limit yourself to enum or other defined types. i.e. What to do when: I MUST USE #define Please comment on my proposed solution below.. _

  Read the article

• How can I request local pages in the background of an ASP.NET MVC app?

  - by flipdoubt

  My ASP.NET MVC app needs to run a set of tasks at startup and in the background at a regular interval. I have implemented each task as a controller action and listed the app-relative path to the action in the database. I implemented a TaskRunner process that gets the urls from the database and requests each one at a regular interval using WebRequest.Create, but this throws a UriFormatException. I cannot use this answer or any code that plucks values from HttpContext.Current.Request without getting an HttpException with the message "Request is not available in this context". The Request object is not available because my code uses System.Threading.Timer to do background processing, as recommended here. Here are my questions: Is there really no way to make local web requests within an ASP.NET web app? Is there really no way to dynamically ascertain the root path to the web app even using static dependencies in ASP.NET? I was trying to avoid storing the app's root path in the database (as FogBugz does with its "Maintenance Path"), but is this best option?

  Read the article

• What to keep in mind when creating your own custom web services API?

  - by John Conde

  I have created a website which allows users to sign up for, and use, an online service. To help promote the website we will be have resellers who will be offering their own branded services through us. The initial plan is to allow resellers to place registration, login, and lost password forms on their own website and use an API created by us to handle these requests. I have begun outlining how I expect the API to work (and starting documenting it as well) and I want to make sure I get it right, or as close to right, as I can from the beginning as I know once you have declared a public API you want to avoid changing that API at all costs. So far I have decided: To have the user pass their account credentials with each request To require SSL for all requests What else should I be keeping in mind?

  Read the article

< Previous Page | 376 377 378 379 380 381 382 383 384 385 386 387  | Next Page >