Search Results

Search found 5192 results on 208 pages for 'random forests'.

Page 71/208 | < Previous Page | 67 68 69 70 71 72 73 74 75 76 77 78  | Next Page >

• How to use boost normal distribution classes?

  - by David Alfonso

  Hi all, I'm trying to use boost::normal_distribution in order to generate a normal distribution with mean 0 and sigma 1. The following code uses boost normal classes. Am I using them correctly? #include <boost/random.hpp> #include <boost/random/normal_distribution.hpp> int main() { boost::mt19937 rng; // I don't seed it on purpouse (it's not relevant) boost::normal_distribution<> nd(0.0, 1.0); boost::variate_generator<boost::mt19937&, boost::normal_distribution<> > var_nor(rng, nd); int i = 0; for (; i < 10; ++i) { double d = var_nor(); std::cout << d << std::endl; } } The result on my machine is: 0.213436 -0.49558 1.57538 -1.0592 1.83927 1.88577 0.604675 -0.365983 -0.578264 -0.634376 As you can see all values are not between -1 and 1. Thank you all in advance!

  Read the article

• SharePoint randomly replacing file names in web parts?

  - by nvuono

  Ok SharePoint is driving me crazy and I need to see if anyone has encountered a similar problem or knows of a solution: I have a content editor webpart with some HTML including links to PDF files that I've modified slightly to append an employee number querystring ie: <a href="http://moss.company.com/group/home/EPermits /Blank%20Form%20Templates/_blank_breach_permit.pdf?empNum=">New Breach Permit</a> And SharePoint seems to randomly replace the filename with aab04168 or some other similar characters: <a href="http://moss.company.com/group/home/EPermits /Blank%20Form%20Templates/aab04168?empNum=">New Breach Permit</a> After this happened a few times with no explanation I tried changing the content editor webpart to look directly at a documentLinks.html file located in the Shared Documents folder of the SharePoint site and guess what... SharePoint edited that document and replaced my filenames with random characters in there too! Figuring that filenames beginning with an underscore could be triggering some internal SharePoint procedures I've renamed all the files to remove the starting underscore--unfortunately the problem isn't immediately reproducible and I'm waiting right now to see if I run into any more trouble. edit: the underscore in the filename didn't help... my documentLinks.html wound up getting modified and all the hrefs were replaced with random characters again. Now I'm setting the hrefs in javascript with the filename text concatenated together from multiple strings. linkEle.href = ".../EPermits/Blank%20Form%20Templates/blank" + "_Chemical_Usage.pdf?empNum=" + empNumber;

  Read the article

• how to implement a really efficient bitvector sorting in python

  - by xiao

  Hello guys! Actually this is an interesting topic from programming pearls, sorting 10 digits telephone numbers in a limited memory with an efficient algorithm. You can find the whole story here What I am interested in is just how fast the implementation could be in python. I have done a naive implementation with the module bitvector. The code is as following: from BitVector import BitVector import timeit import random import time import sys def sort(input_li): return sorted(input_li) def vec_sort(input_li): bv = BitVector( size = len(input_li) ) for i in input_li: bv[i] = 1 res_li = [] for i in range(len(bv)): if bv[i]: res_li.append(i) return res_li if __name__ == "__main__": test_data = range(int(sys.argv[1])) print 'test_data size is:', sys.argv[1] random.shuffle(test_data) start = time.time() sort(test_data) elapsed = (time.time() - start) print "sort function takes " + str(elapsed) start = time.time() vec_sort(test_data) elapsed = (time.time() - start) print "sort function takes " + str(elapsed) start = time.time() vec_sort(test_data) elapsed = (time.time() - start) print "vec_sort function takes " + str(elapsed) I have tested from array size 100 to 10,000,000 in my macbook(2GHz Intel Core 2 Duo 2GB SDRAM), the result is as following: test_data size is: 1000 sort function takes 0.000274896621704 vec_sort function takes 0.00383687019348 test_data size is: 10000 sort function takes 0.00380706787109 vec_sort function takes 0.0371489524841 test_data size is: 100000 sort function takes 0.0520560741425 vec_sort function takes 0.374383926392 test_data size is: 1000000 sort function takes 0.867373943329 vec_sort function takes 3.80475401878 test_data size is: 10000000 sort function takes 12.9204008579 vec_sort function takes 38.8053860664 What disappoints me is that even when the test_data size is 100,000,000, the sort function is still faster than vec_sort. Is there any way to accelerate the vec_sort function?

  Read the article

• how to Compute the average probe length for success and failure - Linear probe (Hash Tables)

  - by fang_dejavu

  hi everyone, I'm doing an assignment for my Data Structures class. we were asked to to study linear probing with load factors of .1, .2 , .3, ...., and .9. The formula for testing is: The average probe length using linear probing is roughly Success-- ( 1 + 1/(1-L)**2)/2 or Failure-- (1+1(1-L))/2. we are required to find the theoretical using the formula above which I did(just plug the load factor in the formula), then we have to calculate the empirical (which I not quite sure how to do). here is the rest of the requirements **For each load factor, 10,000 randomly generated positive ints between 1 and 50000 (inclusive) will be inserted into a table of the "right" size, where "right" is strictly based upon the load factor you are testing. Repeats are allowed. Be sure that your formula for randomly generated ints is correct. There is a class called Random in java.util. USE it! After a table of the right (based upon L) size is loaded with 10,000 ints, do 100 searches of newly generated random ints from the range of 1 to 50000. Compute the average probe length for each of the two formulas and indicate the denominators used in each calculationSo, for example, each test for a .5 load would have a table of size approximately 20,000 (adjusted to be prime) and similarly each test for a .9 load would have a table of approximate size 10,000/.9 (again adjusted to be prime). The program should run displaying the various load factors tested, the average probe for each search (the two denominators used to compute the averages will add to 100), and the theoretical answers using the formula above. .** how do I calculate the empirical success?

  Read the article

• comparing salt and hashed passwords during login doesn't seem work right....

  - by Pandiya Chendur

  I stored salt and hash values of password during user registration... But during their login i then salt and hash the password given by the user, what happens is a new salt and a new hash is generated.... string password = collection["Password"]; reg.PasswordSalt = CreateSalt(6); reg.PasswordHash = CreatePasswordHash(password, reg.PasswordSalt); These statements are in both registration and login.... salt and hash during registration was eVSJE84W and 18DE22FED8C378DB7716B0E4B6C0BA54167315A2 During login it was 4YDIeARH and 12E3C1F4F4CFE04EA973D7C65A09A78E2D80AAC7..... Any suggestion.... public static string CreateSalt(int size) { //Generate a cryptographic random number. RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider(); byte[] buff = new byte[size]; rng.GetBytes(buff); // Return a Base64 string representation of the random number. return Convert.ToBase64String(buff); } public static string CreatePasswordHash(string pwd, string salt) { string saltAndPwd = String.Concat(pwd, salt); string hashedPwd = FormsAuthentication.HashPasswordForStoringInConfigFile( saltAndPwd, "sha1"); return hashedPwd; }

  Read the article

• movieClip in Array displays null, and aren't showing up on stage.addChild(Array[i])

  - by jtdino

  i am new to Actionscript3, i need to know why i keep getting Parameter child must be non-null. And my code won't display 5 enemyBlock objects onto the stage but only just one. any tips and help will be much appreciated. thanks in advance. returns: TypeError: Error #2007: Parameter child must be non-null. at flash.display::DisplayObjectContainer/addChild() at flash.display::Stage/addChild() at BlockDrop_fla::MainTimeline/EnemyBlockPos() at BlockDrop_fla::MainTimeline/frame2() // declare varibles var isEnemyMoving:Boolean = false; var enemyArray:Array; var enemyBlock:MovieClip = new EnemyBlock(); // assign EnemyBlock class to enemyBlock var enemyBlockMC:MovieClip; var count:int = 5; var mapWidth:Number = 800; var mapHeight:Number = 600; function EnemyBlockPos() :void { // assign new MovieClip not null enemyBlockMC = new MovieClip; enemyArray = new Array(); for(var i=1; i<= count; i++){ // add class to MC enemyBlockMC.addChild(enemyBlock); // randomize position enemyBlock.x = Math.round(Math.random()*mapWidth); enemyBlock.y = Math.round(Math.random()*mapHeight); // set motion enemyBlock.movement = 5; // add MC to array enemyArray.push(enemyBlockMC); } for (var w = 1; w <= enemyArray.length; w++) { addChild(enemyArray[w]); } } // endOf EnemyBlockPos

  Read the article

• Function in JS returns undefined

  - by megapool020

  Hello there, I have the following problem. The alert allways returns undefined, but I know it has a value. What am I doing wrong. I'm out of solutions... I'm using JQUERY jquery-1.4.2.min.js Tnx in advance $(document).ready(function(){ $('#generateButton').click(createIBAN); }); function createIBAN(){ //---- First check if a bank has been selected, //---- if not, then show error if($('#selectBank').val()==''){ alert('Selecte a bank!'); }else{ var bankAccount = generateBankAccount(); alert(bankAccount); } return false; } function generateBankAccount(){ //---- Create "elfproef" bankaccount var bankAccount = ''; //---- Set the amount of digits in a bankaccount digitAmount = 9; //---- Make random digitstring for (var i = 0; i < digitAmount; i++) { bankAccount += Math.floor(Math.random() * digitAmount); } //---- validate the string, if not "elf-proef" if (elfProef(bankAccount)==false) { //---- regenerate the string generateBankAccount(); }else{ return bankAccount; } } function elfProef(bankAccount) { //---- set sum to 0 and start the for-loop for counting var sum = 0; for (var i = 0; i < digitAmount; i++) { //---- for every digit multiply it times 9 - number //---- of the digit and count it to the sum var sum += bankAccount.charAt(i) * (digitAmount - i); } //---- Check if sum can be devided by 11 without having ##,## if(sum % 11==0){ //---- return true means string is "elf-proef" return true; }else { //---- String is not "elf-proef", try again return false; } }

  Read the article

• GZipStream in an WebHttpResponse producing no data

  - by Pierre 303

  I want to compress my HTTP Responses for client that supports it. Here is the code used to send a standard response: IHttpClientContext context = (IHttpClientContext)sender; IHttpRequest request = e.Request; string responseBody = "This is some random text"; IHttpResponse response = request.CreateResponse(context); using (StreamWriter writer = new StreamWriter(response.Body)) { writer.WriteLine(responseBody); writer.Flush(); response.Send(); } The code above works fine. Now I added gzip support below. When I test it with a browser that supports gzip or a custom method, it returns an empty string. I'm sure I'm missing something simple, but I just can't find it... IHttpClientContext context = (IHttpClientContext)sender; IHttpRequest request = e.Request; string acceptEncoding = request.Headers["Accept-Encoding"]; string responseBody = "This is some random text"; IHttpResponse response = request.CreateResponse(context); if (acceptEncoding != null && acceptEncoding.Contains("gzip")) { byte[] bytes = ASCIIEncoding.ASCII.GetBytes(responseBody); response.AddHeader("Content-Encoding", "gzip"); using (GZipStream writer = new GZipStream(response.Body, CompressionMode.Compress)) { writer.Write(bytes, 0, bytes.Length); writer.Flush(); response.Send(); } } else { using (StreamWriter writer = new StreamWriter(response.Body)) { writer.WriteLine(responseBody); writer.Flush(); response.Send(); } }

  Read the article

• SQL: Order randomly when inserting objects to a table

  - by Ekaterina

  I have an UDF that selects top 6 objects from a table (with a union - code below) and inserts it into another table. (btw SQL 2005) So I paste the UDF below and what the code does is: selects objects for a specific city and add a level to those (from table Europe) union that selection with a selection from the same table for objects that are from the same country and add a level to those From the union, selection is made to get top 6 objects, order by level, so the objects from the same city will be first, and if there aren't any available, then objects from the same country will be returned from the selection. And my problem is, that I want to make a random selection to get random objects from table Europe, but because I insert the result of my selection into a table, I can't use order by newid() or rand() function because they are time-dependent, so I get the following errors: Invalid use of side-effecting or time-dependent operator in 'newid' within a function. Invalid use of side-effecting or time-dependent operator in 'rand' within a function. UDF: ALTER FUNCTION [dbo].[Objects] (@id uniqueidentifier) RETURNS @objects TABLE ( ObjectId uniqueidentifier NOT NULL, InternalId uniqueidentifier NOT NULL ) AS BEGIN declare @city varchar(50) declare @country int select @city = city, @country = country from Europe where internalId = @id insert @objects select @id, internalId from ( select distinct top 6 [level], internalId from ( select top 6 1 as [level], internalId from Europe N4 where N4.city = @city and N4.internalId != @id union select top 6 2 as [level], internalId from Europe N5 where N5.countryId = @country and N5.internalId != @id ) as selection_1 order by [level] ) as selection_2 return END If you have fresh ideas, please share them with me. (Just please, don't suggest to order by newid() or to add a column rand() with seed DateTime (by ms or sthg), because that won't work.)

  Read the article

• pthread_exit and/or pthread_join causing Abort and SegFaults.

  - by MJewkes

  The following code is a simple thread game, that switches between threads causing the timer to decrease. It works fine for 3 threads, causes and Abort(core dumped) for 4 threads, and causes a seg fault for 5 or more threads. Anyone have any idea why this might be happening? #include <stdio.h> #include <stdlib.h> #include <pthread.h> #include <errno.h> #include <assert.h> int volatile num_of_threads; int volatile time_per_round; int volatile time_left; int volatile turn_id; int volatile thread_running; int volatile can_check; void * player (void * id_in){ int id= (int)id_in; while(1){ if(can_check){ if (time_left<=0){ break; } can_check=0; if(thread_running){ if(turn_id==id-1){ turn_id=random()%num_of_threads; time_left--; } } can_check=1; } } pthread_exit(NULL); } int main(int argc, char *args[]){ int i; int buffer; pthread_t * threads =(pthread_t *)malloc(num_of_threads*sizeof(pthread_t)); thread_running=0; num_of_threads=atoi(args[1]); can_check=0; time_per_round = atoi(args[2]); time_left=time_per_round; srandom(time(NULL)); //Create Threads for (i=0;i<num_of_threads;i++){ do{ buffer=pthread_create(&threads[i],NULL,player,(void *)(i+1)); }while(buffer == EAGAIN); } can_check=1; time_left=time_per_round; turn_id=random()%num_of_threads; thread_running=1; for (i=0;i<num_of_threads;i++){ assert(!pthread_join(threads[i], NULL)); } return 0; }

  Read the article

• What are some methods to prevent double posting in a form? (PHP)

  - by jpjp

  I want to prevent users from accidentally posting a comment twice. I use the PRG (post redirect get) method, so that I insert the data on another page then redirect the user back to the page which shows the comment. This allows users to refresh as many times as they want. However this doesn't work when the user goes back and clicks submit again or when they click submit 100 times really fast. I don't want 100 of the same comments. I looked at related questions on SO and found that a token is best. But I am having trouble using it. //makerandomtoken(20) returns a random 20 length char. <form method="post" ... > <input type="text" id="comments" name="comments" class="commentbox" /><br/> <input type="hidden" name="_token" value="<?php echo $token=makerandomtoken(20); ?>" /> <input type="submit" value="submit" name="submit" /> </form> if (isset($_POST['submit']) && !empty($comments)) { $comments= mysqli_real_escape_string($dbc,trim($_POST['comments'])); //how do I make the if-statment to check if the token has been already set once? if ( ____________){ //don't insert comment because already clicked submit } else{ //insert the comment into the database } } So I have the token as a hidden value, but how do I use that to prevent multiple clicking of submit. METHODS: someone suggested using sessions. I would set the random token to $_SESSION['_token'] and check if that session token is equal to the $_POST['_token'], but how do I do that? When I tried, it still doesn't check

  Read the article

• SSL over TDS, SQL Server 2005 Express

  - by reuvenab

  I capture packets sent/received by Win Xp machine when connecting to SQL Server 2005 Express using TLS encryption. Server and Client exchange Hello messages Server and Client send ChangeCipherSpec message Then Server and Client server send strange message that is not described in TLS protocol What is the message and if SSL over TDS is standard compliant at all? Server side capture: 16 **SSL Handshake** 03 01 00 4a 02 ServerHello 00 00 46 03 01 4b dd 68 59 GMT 33 13 37 98 10 5d 57 9d ff 71 70 dc d6 6f 9e 2c Random[00..13] cb 96 c0 2e b3 2f 9b 74 67 05 cc 96 Random[14..27] 20 72 26 00 00 0f db 7f d9 b0 51 c2 4f cd 81 4c Session ID 3f e3 d2 d1 da 55 c0 fe 9b 56 b7 6f 70 86 fe bb Session ID 54 Session ID 00 04 Cipher Suite 00 Compression 14 03 01 00 01 01 **ChangeCipherSpec** 16 03 01 ???? Finished ??? 00 20 d0 da cc c4 36 11 43 ff 22 25 8a e1 38 2b ???? ??? 71 ce f3 59 9e 35 b0 be b2 4b 1d c5 21 21 ce 41 ???? ??? 8e 24

  Read the article

• using a While loop to control the value of a keyframe in a timeline in Javafx

  - by dragoknight

  i want to create an animation where the ball will move in one of the 4 sectors of a circle randomly.this will happen 5 times.so,i create a while loop(i<5) and call the random function.i then create an if loop and attach some x and y values according to the random fn value.i then create an timeline object inside the while loop and in the key frame value,i use these x and y values.but when i run the program,what happens is that all the values are being created(x and y values seen through println) but only the last x and y value(for i=5)is being rendered in the screen.the animations for the previous values(1<=i<=4)are not being rendered.Please advise where have i gone wrong? public function run(args:String[]) { var i=0; while(i<5) { var z=gety(); println(z); // var relativeTime:Duration=0s; if(z==1) {xbind=120; ybind=80; } else if(z==2) {xbind=120; ybind=120; } else if(z==3) { xbind=80; ybind=120; } else if(z==4) { xbind=80; ybind=80; } var t:Timeline=Timeline{ //time: bind pos with inverse; repeatCount: Timeline.INDEFINITE autoReverse: true keyFrames: [ KeyFrame{ time: 0s values: [ x => 100.0,y => 100.0]}, KeyFrame{time: 2s values:[x => xbind tween Interpolator.LINEAR, y => ybind tween Interpolator.LINEAR,] }, ] }//end timeline i++; t.play(); Thread.sleep(2000); }//end while }

  Read the article

• Rails database relationships

  - by Danny McClelland

  Hi Everyone, I have three models that I want to interact with each other. Kase, Person and and Company. I have (I think) setup the relationships correctly: class Kase < ActiveRecord::Base #HAS ONE COMPANY has_one :company #HAS MANY PERSONS has_many :persons class Person < ActiveRecord::Base belongs_to :company class Company < ActiveRecord::Base has_many :persons def to_s; companyname; end I have put the select field on the create new Kase view, and the create new Person view as follows: <li>Company<span><%= f.select :company_id, Company.all %> </span></li> All of the above successfully shows a drop down menu dynamically populated with the company names within Companies. What I am trying to do is display the contact of the Company record within the kase and person show.html.erb. For example, If I have a company called "Acme, Inc." and create a new Kase called "Random Case" and choose within the create new case page "Acme, Inc." from the companies drop down menu. I would then want to display "Acme, Inc" along with "Acme, Inc. Mobile" etc. on the "Random Case" show.html.erb. I hope this makes sense to somebody! Thanks, Danny

  Read the article

• Ruby shortest/most efficient way to write rnd hex

  - by Whirlwin

  Hi. What I have is a method used to generate random hex values. E.g 666 or FF7 However, I don't think it is efficient at all.. What I want is to make it more efficient which perhaps will make my code shorter as well, but I don't know how. That is why I need tips or hints Here is my code so far: def random_values random_values = Array.new letters = ['A','B','C','D','E','F'] for i in 1..15 if i <= 9 random_values << i else random_values << letters[i-10] end end return random_values.shuffle[0].to_s + random_values.shuffle[0].to_s + random_values.shuffle[0].to_s end As you probably see, I do not generate random numbers. I just shuffle the array containing the values I want, meaning all the numbers in the array are unique, which is not needed, but was the easiest solution for me when I wrote the code. I am most concerned about the return line.. If only it was possible to write like: return 3.times { random_values.shuffle[0] } or return random_values.shuffle[0].to_s *3 Thanks in advance!

  Read the article

• How to parallelize this groovy code?

  - by lucas

  I'm trying to write a reusable component in Groovy to easily shoot off emails from some of our Java applications. I would like to pass it a List, where Email is just a POJO(POGO?) with some email info. I'd like it to be multithreaded, at least running all the email logic in a second thread, or make one thread per email. I am really foggy on multithreading in Java so that probably doesn't help! I've attempted a few different ways, but here is what I have right now: void sendEmails(List<Email> emails) { def threads = [] def sendEm = emails.each{ email -> def th = new Thread({ Random rand = new Random() def wait = (long)(rand.nextDouble() * 1000) println "in closure" this.sleep wait sendEmail(email) }) println "putting thread in list" threads << th } threads.each { it.run() } threads.each { it.join() } } I was hoping the sleep would randomly slow some threads down so the console output wouldn't be sequential. Instead, I see this: putting thread in list putting thread in list putting thread in list putting thread in list putting thread in list putting thread in list putting thread in list putting thread in list putting thread in list putting thread in list in closure sending email1 in closure sending email2 in closure sending email3 in closure sending email4 in closure sending email5 in closure sending email6 in closure sending email7 in closure sending email8 in closure sending email9 in closure sending email10 sendEmail basically does what you'd expect, including the println statement, and the client that calls this follows, void doSomething() { Mailman emailer = MailmanFactory.getExchangeEmailer() def to = ["one","two"] def from = "noreply" def li = [] def email (1..10).each { email = new Email(to,null,from,"email"+it,"hello") li << email } emailer.sendEmails li }

  Read the article

• ImageViews sometimes not displaying in FrameLayout activity

  - by Ken

  The top level layout in my activity is a framelayout. I have completed, debugged and tested this app and it works exactly like it should in all respects on my g1 and on various emulators. But on 3.7-inch displays running 2.1+, some imageviews packed in a linearlayout are periodically not visible. I know that they are there because you can touch and drag them with effect in the app. So I assume somehow they have gotten under the SurfaceView that is the main component of the app. This is apparently so even though the SurfaceView is declared in the xml prior to the LinearLayout. However, the ImageViews IN the LinearLayout are added programmatically towards the end of onCreate(). Framelayout stacks everything that is added to it, one on top of the other--the only way you will see more than one child of a frame layout is if they are smaller than the screen and are placed apart from eachother. Oddly, sometimes the imageviews ARE visible--it is random. Anyway, I've been trying to combat this with framelayout.bringChildToFront(View v) on the linearlayout without success. I wonder if anyone has any insight into how the behavior could be random like that, and how I should code these imageviews to keep this from happening, and why the problem appears only to occur on 3.7 vs 3.2 inch screens (as it happens, the two 3.2-inch screens were both htc, so vendor might be factor too). [edit] Actually, I've determined that this is a 2.2 issue, not a screen size (or even vendor) issue. Can't ensure that ImageViews added to a framelayout with a SurfaceView in it will appear on top of the surfaceview. I ran some tests in the respective onDraw() methods and the imageviews are 'visible' (0), and nothing does anything to the alpha of the drawables, which are there as well at ondraw(). [/edit] Any insight would be welcomed. Ken T.

  Read the article

• For loop index out of range ArgumentOutOfRangeException when multithreading

  - by Lirik

  I'm getting some strange behavior... when I iterate over the dummyText List in the ThreadTest method I get an index out of range exception (ArgumentOutOfRangeException), but if I remove the threads and I just print out the text, then everything works fine. This is my main method: public static Object sync = new Object(); static void Main(string[] args) { ThreadTest(); Console.WriteLine("Press any key to continue."); Console.ReadKey(); } This method throws the exception: private static void ThreadTest() { Console.WriteLine("Running ThreadTest"); Console.WriteLine("Running ThreadTest"); List<String> dummyText = new List<string>() { "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten"}; for (int i = 0; i < dummyText.Count; i++) { Thread t = new Thread(() => PrintThreadName(dummyText[i])); // <-- Index out of range?!? t.Name = ("Thread " + (i)); t.IsBackground = true; t.Start(); } } private static void PrintThreadName(String text) { Random rand = new Random(DateTime.Now.Millisecond); while (true) { lock (sync) { Console.WriteLine(Thread.CurrentThread.Name + " running " + text); Thread.Sleep(1000+rand.Next(0,2000)); } } } This does not throw the exception: private static void ThreadTest() { Console.WriteLine("Running ThreadTest"); List<String> dummyText = new List<string>() { "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten"}; for (int i = 0; i < dummyText.Count; i++) { Console.WriteLine(dummyText[i]); // <-- No exception here } } Does anybody know why this is happening?

  Read the article

• Out of memory when creating a lot of objects C#

  - by Bas

  I'm processing 1 million records in my application, which I retrieve from a MySQL database. To do so I'm using Linq to get the records and use .Skip() and .Take() to process 250 records at a time. For each retrieved record I need to create 0 to 4 Items, which I then add to the database. So the average amount of total Items that has to be created is around 2 million. while (objects.Count != 0) { using (dataContext = new LinqToSqlContext(new DataContext())) { foreach (Object objectRecord in objects) { // Create a list of 0 - 4 Random Items and add each Item to the Object for (int i = 0; i < Random.Next(0, 4); i++) { Item item = new Item(); item.Id = Guid.NewGuid(); item.Object = objectRecord.Id; item.Created = DateTime.Now; item.Changed = DateTime.Now; dataContext.InsertOnSubmit(item); } } dataContext.SubmitChanges(); } amountToSkip += 250; objects = objectCollection.Skip(amountToSkip).Take(250).ToList(); } Now the problem arises when creating the Items. When running the application (and not even using dataContext) the memory increases consistently. It's like the items are never getting disposed. Does anyone notice what I'm doing wrong? Thanks in advance!

  Read the article

• Being pressured to GOTO the dark-side

  - by Dan McG

  We have a situation at work where developers working on a legacy (core) system are being pressured into using GOTO statements when adding new features into existing code that is already infected with spagetti code. Now, I understand there may be arguments for using 'just one little GOTO' instead of spending the time on refactoring to a more maintainable solution. The issue is, this isolated 'just one little GOTO' isn't so isolated. At least once every week or so there is a new 'one little GOTO' to add. This codebase is already a horror to work with due to code dating back to or before 1984 being riddled with GOTOs that would make many Pastafarians believe it was inspired by the Flying Spagetti Monster itself. Unfortunately the language this is written in doesn't have any ready made refactoring tools, so it makes it harder to push the 'Refactor to increase productivity later' because short-term wins are the only wins paid attention to here... Has anyone else experienced this issue whereby everybody agrees that we cannot be adding new GOTOs to jump 2000 lines to a random section, but continually have Anaylsts insist on doing it just this one time and having management approve it? tldr; How can one go about addressing the issue of developers being pressured (forced) to continually add GOTO statements (by add, I mean add to jump to random sections many lines away) because it 'gets that feature in quicker'? I'm beginning to fear we may loses valuable developers to the raptors over this...

  Read the article

• Seeding many to many tables with Entity Framework

  - by Doozer1979

  I have a meeting entity and a users entity which have a many to many relationship. I'm using Autopoco to create seed data for the Users and meetings How do i seed the UserMeetings linking table that is created by EntityFramework with seed data? The linking table has two fields in it; User_Id, and Meeting_ID. I'm looping through the list of users that autopoco creates and attaching a random number of meetings Here's what i've got so far. foreach (var user in userList) { var rand = new Random(); var amountOfMeetingsToAdd = rand.Next(1, 300); for (var i = 0; i <= amountOfMeetingsToAdd; i++) { var randomMeeting = rand.Next(1, MeetingRecords); //Error occurs on This line user.Meetings.Add(_meetings[randomMeeting]); } } I got an 'Object reference not set to an instance of an object.' even though the meeting record that i'm trying to attach does exist. For info all this is happening prior to me saving the context to the DB.

  Read the article

• Basic security, PHP mySQl

  - by yuudachi

  So I am making a basic log-in page. I have a good idea of what to do, but I'm still unsure of some things. I have a database full of students and a password column of course. I know I'm going to use md5 encryption in that column. The student enters their e-mail and student ID, and they get e-mailed a password if correct. But, where do I create the password? Do I have to manually add the password (which is just a randomly generated string) in mySQL to all the students? And I am suppose to send the password to the student; how will I know what to send the student if the password is encrypted? I was thinking about generating the password when the student first enters their e-mail and student ID. They get an e-mail of the random string, and at the same time, I add the same random string to the database, encrypted. Is that how it's suppose to work though? And it feels unsafe doing that all on the same page. Sorry for the long-winded, newbish question. I find this all facisnating at the same time as well (AES and RSA encryption :O)

  Read the article

• Groovy & Grails Concurrency ( quartz, executor )

  - by Pietro

  What I'm trying to do is to run multiple threads at some starting time. Those threads must stay alive for 90minutes after start. During the 90minutes they execute something after a random sleep time (ex: 5minutes to 15minutes). Here is a pseudo code on how I would implement it. The problem is that doing it in this way the threads run in an unexpected way. How can I implement correctly something like this? Class MyJob { static triggers = { cron name: 'first', cronExpression: "0 30 21 * * FRI" cron name: 'second', cronExpression: "0 30 19 * * FRI" cron name: 'third', cronExpression: "0 30 17 * * FRI" def myService def execute() { switch( between trigger name ) case 'first': model = Model.findByAttribute(...) ... myService.run( model, start_time ) break; ... } } class MyService { def run( model, start_time ) { def end_time = end_time.plusMinutes(90) model.fields.each( field -> Thread.start { executeSomeTasks( field, start_time, end_time ) } ) } def executeSomeTasks( field, start_time, end_time ) { while( start_time < end_time ) { ...do something ... sleep( Random.nextInt( 1000 ) ); } } }

  Read the article

• How does the receiver of a cipher text know the IV used for encryption?

  - by PatrickL

  If a random IV is used in encrypting plain text, how does the receiver of the cipher text know what the IV is in order to decrypt it? This is a follow-up question to a response to the previous stackoverflow question on IVs here. The IV allows for plaintext to be encrypted such that the encrypted text is harder to decrypt for an attacker. Each bit of IV you use will double the possibilities of encrypted text from a given plain text. The point is that the attacker doesn't know what the IV is and therefore must compute every possible IV for a given plain text to find the matching cipher text. In this way, the IV acts like a password salt. Most commonly, an IV is used with a chaining cipher (either a stream or block cipher). ... So, if you have a random IV used to encrypt the plain text, how do you decrypt it? Simple. Pass the IV (in plain text) along with your encrypted text. Wait. You just said the IV is randomly generated. Then why pass it as plain text along with the encrypted text?

  Read the article

• Ruby shortest way to write rnd hex

  - by Whirlwin

  Hi. What I have is a method used to generate random hex values. E.g 666 or FF7 However, I don't think it looks simple/elegant at all.. What I want is to make it more simple which perhaps will make my code shorter as well, but I don't know how. That is why I need tips or hints Here is my code so far: def random_values random_values = Array.new letters = ['A','B','C','D','E','F'] for i in 1..15 if i <= 9 random_values << i else random_values << letters[i-10] end end return random_values.shuffle[0].to_s + random_values.shuffle[0].to_s + random_values.shuffle[0].to_s end As you probably see, I do not generate random numbers. I just shuffle the array containing the values I want, meaning all the numbers in the array are unique, which is not needed, but was the easiest solution for me when I wrote the code. I am most concerned about the return line.. If only it was possible to write like: return 3.times { random_values.shuffle[0] } or return random_values.shuffle[0].to_s *3 Thanks in advance!

  Read the article

< Previous Page | 67 68 69 70 71 72 73 74 75 76 77 78  | Next Page >