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Search found 78653 results on 3147 pages for 'performance object name s'.

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  • 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?

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  • one two-directed tcp socket of two one-directed? (linux, high volume, low latency)

    - by osgx
    Hello I need to send (interchange) a high volume of data periodically with the lowest possible latency between 2 machines. The network is rather fast (e.g. 1Gbit or even 2G+). Os is linux. Is it be faster with using 1 tcp socket (for send and recv) or with using 2 uni-directed tcp sockets? The test for this task is very like NetPIPE network benchmark - measure latency and bandwidth for sizes from 2^1 up to 2^13 bytes, each size sent and received 3 times at least (in teal task the number of sends is greater. both processes will be sending and receiving, like ping-pong maybe). The benefit of 2 uni-directed connections come from linux: http://lxr.linux.no/linux+v2.6.18/net/ipv4/tcp_input.c#L3847 3847/* 3848 * TCP receive function for the ESTABLISHED state. 3849 * 3850 * It is split into a fast path and a slow path. The fast path is 3851 * disabled when: ... 3859 * - Data is sent in both directions. Fast path only supports pure senders 3860 * or pure receivers (this means either the sequence number or the ack 3861 * value must stay constant) ... 3863 * 3864 * When these conditions are not satisfied it drops into a standard 3865 * receive procedure patterned after RFC793 to handle all cases. 3866 * The first three cases are guaranteed by proper pred_flags setting, 3867 * the rest is checked inline. Fast processing is turned on in 3868 * tcp_data_queue when everything is OK. All other conditions for disabling fast path is false. And only not-unidirected socket stops kernel from fastpath in receive

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  • Python re module becomes 20 times slower when called on greater than 101 different regex

    - by Wiil
    My problem is about parsing log files and removing variable parts on each lines to be able to group them. For instance: s = re.sub(r'(?i)User [_0-9A-z]+ is ', r"User .. is ", s) s = re.sub(r'(?i)Message rejected because : (.*?) \(.+\)', r'Message rejected because : \1 (...)', s) I have about 120+ matching rules like those above. I have found no performances issues while searching successively on 100 different regex. But a huge slow down comes when applying 101 regex. Exact same behavior happens when replacing my rules set by for a in range(100): s = re.sub(r'(?i)caught here'+str(a)+':.+', r'( ... )', s) Got 20 times slower when putting range(101) instead. # range(100) % ./dashlog.py file.bz2 == Took 2.1 seconds. == # range(101) % ./dashlog.py file.bz2 == Took 47.6 seconds. == Why such thing is happening ? And is there any known workaround ? (Happens on Python 2.6.6/2.7.2 on Linux/Windows.)

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  • same flash file (.swf) downloaded multiple times on a page

    - by Gunjan
    I have a page that has a table with each row corresponding to an audio file. The last cell in each row embeds a simple flash audio player. The problem is that the flash file for the player is being downloaded for each row separately and as soon as rows go beyond 40-50 it crashes the browser. I tried using different players (1pixelout, flash-mp3-player) and the problem is still there, so its not a player specific issue. Is there any way to cache the player so that it is only downloaded once?

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  • Find Exact difference between two dates

    - by iPhone Fun
    Hi all , I want some changes in the date comparison. In my application I am comparing two dates and getting difference as number of Days, but if there is only one day difference the system shows me 0 as a difference of days. I do use following code NSDateFormatter *date_formater=[[NSDateFormatter alloc]init]; [date_formater setDateFormat:@"MMM dd,YYYY"]; NSString *now=[NSString stringWithFormat:@"%@",[date_formater stringFromDate:[NSDate date]]]; LblTodayDate.text = [NSString stringWithFormat:@"%@",[NSString stringWithFormat:@"%@",now]]; NSDate *dateofevent = [[NSUserDefaults standardUserDefaults] valueForKey:@"CeremonyDate_"]; NSDate *endDate =dateofevent; NSDate *startDate = [NSDate date]; gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar]; unsigned int unitFlags = NSDayCalendarUnit; NSDateComponents *components = [gregorian components:unitFlags fromDate:startDate toDate:endDate options:0]; int days = [components day]; I found some solutions that If we make the time as 00:00:00 for comparision then it will show me proper answer , I am right or wrong i don't know. Please help me to solve the issue

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  • Are closures in javascript recompiled

    - by Discodancer
    Let's say we have this code (forget about prototypes for a moment): function A(){ var foo = 1; this.method = function(){ return foo; } } var a = new A(); is the inner function recompiled each time the function A is run? Or is it better (and why) to do it like this: function method = function(){ return this.foo; } function A(){ this.foo = 1; this.method = method; } var a = new A(); Or are the javascript engines smart enough not to create a new 'method' function every time? Specifically Google's v8 and node.js. Also, any general recommendations on when to use which technique are welcome. In my specific example, it really suits me to use the first example, but I know thath the outer function will be instantiated many times.

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  • Create facebook object each and every time?

    - by oshirowanen
    I have a login page which will log a user into my webapp based on their facebook login details. I then create a session to remember who they are. What I want to know is, should I be creating and/or checking the facebook credential on every single page of my webapp, or should I simply use the session I create at the beginning to login? For example, once they have logged in, I would like to allow them to post a message onto their own facebook wall from my app. Should I check the login credentials before they can post by recreating the facebook object, or should I simply use the stored login details already in my session and use that to post to their facebook wall?

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  • Tracking down slow managed DLL loading

    - by Alex K
    I am faced with the following issue and at this point I feel like I'm severely lacking some sort of tool, I just don't know what that tool is, or what exactly it should be doing. Here is the setup: I have a 3rd party DLL that has to be registered in GAC. This all works fine and good on pretty much every machine our software was deployed on before. But now we got 2 machines, seemingly identical to the ones we know work (they are cloned from the same image and stuffed with the same hardware, so pretty much the only difference is software settings, over which I went over and over, and they seem fine). Now the problem, the DLL in GAC takes a very long time to load. At least I believe this is the issue, what I can say definitively is that instantiating a single class from that DLL is the slow part. Once it is loaded, thing fly as they always have. But while on known-good machines the DLL loads so fast that a timestamp in the log doesn't even change, on these 2 machines it take over 1min to load. Knowns: I have no access to the source, so I can't debug through the DLL. Our app is the only one that uses it (so shouldn't be simultaneous access issues). There is only one version of this DLL in existance, so it shouldn't be a matter of version conflict. The GAC reference is being used (if I uninstall the DLL from GAC, an exception will be thrown about the missing GAC reference). Could someone with a greater skill in debug-fu suggest what I can do to track down the root cause of this issue?

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  • How to set xmlns when serializing object in c#

    - by John
    I am serializing an object in my ASP.net MVC program to an xml string like this; StringWriter sw = new StringWriter(); XmlSerializer s = new XmlSerializer(typeof(mytype)); s.Serialize(sw, myData); Now this give me this as the first 2 lines; <?xml version="1.0" encoding="utf-16"?> <GetCustomerName xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> my question is, How can I change the xmlns and the encoding type, when serializing? Thanks

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  • Spring Web application internal visual monitoring heap space and permgen.

    - by Veniamin
    If I have created web application used Spring framework(based on maven), can I include some module/dependency/plugin into my app to monitor Heap space, Permgen, etc. It whould be greate to get some charts output likes as in VisuaVM. For example: http://localhost:8080/monitoring = Including something likes VisualVM I have found next dependency without link to repo: <dependency> <groupId>com.sun.tools.visualvm</groupId> <artifactId>core</artifactId> <version>1.3.3</version> </dependency> How to use it?

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  • Initial capacity of collection types, i.e. Dictionary, List

    - by Neil N
    Certain collection types in .Net have an optional "Initial Capacity" constructor param. i.e. Dictionary<string, string> something = new Dictionary<string,string>(20); List<string> anything = new List<string>(50); I can't seem to find what the default initial capacity is for these objects on MSDN. If I know I will only be storing 12 or so items in a dictionary, doesn't it make sense to set the initial capacity to something like 20? My reasoning is, assuming the capacity grows like it does for a StringBuiler, which doubles each time the capacity is hit, and each re-allocation is costly, why not pre-set the size to something you know will hold your data, with some extra room just in case? If the initial capacity is 100, and I know I will only need a dozen or so, it seems as though the rest of that allocated RAM is allocated for nothing. Please spare me the "premature optimization" speil for the O(n^n)th time. I know it won't make my apps any faster or save any meaningful amount of memory, this is mostly out of curiosity.

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  • Rails: Ajax-enabled form without a model object

    - by Caffeine Coma
    I'm new to Rails and having a hard time figuring out how to create a form that submits over Ajax without having a corresponding model object. My use case is a simple form that collects an email address and sends it an email; there's nothing to be persisted, so no model. In cases where I do have a model, I've had success with form_for(@model, remote: true). I can't seem to find the right helper for the case where there is no model. I tried form_tag(named_path, remote: true) and that works, but does not use Ajax. Pointers to an example with an example with a proper controller, .html.erb and routes.rb would be really appreciated.

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  • Reasonably faster way to traverse a directory tree in Python?

    - by Sridhar Ratnakumar
    Assuming that the given directory tree is of reasonable size: say an open source project like Twisted or Python, what is the fastest way to traverse and iterate over the absolute path of all files/directories inside that directory? I want to do this from within Python (subprocess is allowed). os.path.walk is slow. So I tried ls -lR and tree -fi. For a project with about 8337 files (including tmp, pyc, test, .svn files): $ time tree -fi > /dev/null real 0m0.170s user 0m0.044s sys 0m0.123s $ time ls -lR > /dev/null real 0m0.292s user 0m0.138s sys 0m0.152s $ time find . > /dev/null real 0m0.074s user 0m0.017s sys 0m0.056s $ tree appears to be faster than ls -lR (though ls -R is faster than tree, but it does not give full paths). find is the fastest. Can anyone think of a faster and/or better approach? On Windows, I may simply ship a 32-bit binary tree.exe or ls.exe if necessary. Update 1: Added find

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  • SQL Server uncorrelated subquery very slow

    - by brianberns
    I have a simple, uncorrelated subquery that performs very poorly on SQL Server. I'm not very experienced at reading execution plans, but it looks like the inner query is being executed once for every row in the outer query, even though the results are the same each time. What can I do to tell SQL Server to execute the inner query only once? The query looks like this: select * from Record record0_ where record0_.RecordTypeFK='c2a0ffa5-d23b-11db-9ea3-000e7f30d6a2' and ( record0_.EntityFK in ( select record1_.EntityFK from Record record1_ join RecordTextValue textvalues2_ on record1_.PK=textvalues2_.RecordFK and textvalues2_.FieldFK = '0d323c22-0ec2-11e0-a148-0018f3dde540' and (textvalues2_.Value like 'O%' escape '~') ) )

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  • Using enums or a set of classes when I know I have a finite set of different options?

    - by devoured elysium
    Let's say I have defined the following class: public abstract class Event { public DateTime Time { get; protected set; } protected Event(DateTime time) { Time = time; } } What would you prefer between this: public class AsleepEvent : Event { public AsleepEvent(DateTime time) : base(time) { } } public class AwakeEvent : Event { public AwakeEvent(DateTime time) : base(time) { } } and this: public enum StateEventType { NowAwake, NowAsleep } public class StateEvent : Event { protected StateEventType stateType; public MealEvent(DateTime time, StateEventType stateType) : base(time) { stateType = stateType; } } and why? I am generally more inclined to the first option, but I can't explain why. Is it totally the same or are any advantages in using one instead of the other? Maybe with the first method its easier to add more "states", altough in this case I am 100% sure I will only want two states: now awake, and now asleep (they signal the moments when one awakes and one falls asleep).

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  • Time complexity O() of isPalindrome()

    - by Aran
    I have this method, isPalindrome(), and I am trying to find the time complexity of it, and also rewrite the code more efficiently. boolean isPalindrome(String s) { boolean bP = true; for(int i=0; i<s.length(); i++) { if(s.charAt(i) != s.charAt(s.length()-i-1)) { bP = false; } } return bP; } Now I know this code checks the string's characters to see whether it is the same as the one before it and if it is then it doesn't change bP. And I think I know that the operations are s.length(), s.charAt(i) and s.charAt(s.length()-i-!)). Making the time-complexity O(N + 3), I think? This correct, if not what is it and how is that figured out. Also to make this more efficient, would it be good to store the character in temporary strings?

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  • Strange Error - "Object moved to here."

    - by Dkong
    I get the strange error "Object moved to here." on a blank white page when I try to login on a site I created. It works fine locally but not when I deploy it to the test or production server. I am not doing anything odd, just using basic authentication code in a helper function as follows... public static bool AuthenticateUser(string Username, string Password, bool PersistLogin, string RedirectionURL) { if (Membership.ValidateUser(Username, Password)) { FormsAuthentication.SetAuthCookie(Username, PersistLogin); HttpContext.Current.Response.Redirect(RedirectionURL,true); return true; } else return false; }

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  • C#: why have all static methods/variables in a non-static class?

    - by Craig Johnston
    I have come across a class which is non-static, but all the methods and variables are static. Eg: public class Class1 { private static string String1 = "one"; private static string String2 = "two"; public static void PrintStrings(string str1, string str2) { ... All the variables are static across all instances, so there is no point having separate instances of the class. Is there any reason to create a class such as this?

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  • C# Linq: Restructuring object

    - by Ben
    I'd like to take an object like this: SortedList<string, SortedList<int, SortedList<DateTime, double>>> Data and, for a given 'int' value (key of first nested sorted list), restructure it like this: SortedList<DateTime, SortedList<string, double>> or, better yet, this: SortedList<DateTime, double[]> where each 'double[]' has as many elements as there are KeyValue pairs in the SortedList. I'm guessing Linq is the way to go, but can't figure it out. Thanks for any suggestions.

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