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  • Round date to 10 minutes interval

    - by Peter Lang
    I have a DATE column that I want to round to the next-lower 10 minute interval in a query (see example below). I managed to do it by truncating the seconds and then subtracting the last digit of minutes. WITH test_data AS ( SELECT TO_DATE('2010-01-01 10:00:00', 'YYYY-MM-DD HH24:MI:SS') d FROM dual UNION SELECT TO_DATE('2010-01-01 10:05:00', 'YYYY-MM-DD HH24:MI:SS') d FROM dual UNION SELECT TO_DATE('2010-01-01 10:09:59', 'YYYY-MM-DD HH24:MI:SS') d FROM dual UNION SELECT TO_DATE('2010-01-01 10:10:00', 'YYYY-MM-DD HH24:MI:SS') d FROM dual UNION SELECT TO_DATE('2099-01-01 10:00:33', 'YYYY-MM-DD HH24:MI:SS') d FROM dual ) -- #end of test-data SELECT d, TRUNC(d, 'MI') - MOD(TO_CHAR(d, 'MI'), 10) / (24 * 60) FROM test_data And here is the result: 01.01.2010 10:00:00    01.01.2010 10:00:00 01.01.2010 10:05:00    01.01.2010 10:00:00 01.01.2010 10:09:59    01.01.2010 10:00:00 01.01.2010 10:10:00    01.01.2010 10:10:00 01.01.2099 10:00:33    01.01.2099 10:00:00 Works as expected, but is there a better way? EDIT: I was curious about performance, so I did the following test with 500.000 rows and (not really) random dates. I am going to add the results as comments to the provided solutions. DECLARE t TIMESTAMP := SYSTIMESTAMP; BEGIN FOR i IN ( WITH test_data AS ( SELECT SYSDATE + ROWNUM / 5000 d FROM dual CONNECT BY ROWNUM <= 500000 ) SELECT TRUNC(d, 'MI') - MOD(TO_CHAR(d, 'MI'), 10) / (24 * 60) FROM test_data ) LOOP NULL; END LOOP; dbms_output.put_line( SYSTIMESTAMP - t ); END; This approach took 03.24 s.

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  • Largest triangle from a set of points

    - by Faken
    I have a set of random points from which i want to find the largest triangle by area who's verticies are each on one of those points. So far I have figured out that the largest triangle's verticies will only lie on the outside points of the cloud of points (or the convex hull) so i have programmed a function to do just that (using Graham scan in nlogn time). However that's where I'm stuck. The only way I can figure out how to find the largest triangle from these points is to use brute force at n^3 time which is still acceptable in an average case as the convex hull algorithm usually kicks out the vast majority of points. However in a worst case scenario where points are on a circle, this method would fail miserably. Dose anyone know an algorithm to do this more efficiently? Note: I know that CGAL has this algorithm there but they do not go into any details on how its done. I don't want to use libraries, i want to learn this and program it myself (and also allow me to tweak it to exactly the way i want it to operate, just like the graham scan in which other implementations pick up collinear points that i don't want).

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  • How to map a test onto a list of numbers

    - by Arthur Ulfeldt
    I have a function with a bug: user> (-> 42 int-to-bytes bytes-to-int) 42 user> (-> 128 int-to-bytes bytes-to-int) -128 user> looks like I need to handle overflow when converting back... Better write a test to make sure this never happens again. This project is using clojure.contrib.test-is so i write: (deftest int-to-bytes-to-int (let [lots-of-big-numbers (big-test-numbers)] (map #(is (= (-> % int-to-bytes bytes-to-int) %)) lots-of-big-numbers))) This should be testing converting to a seq of bytes and back again produces the origional result on a list of 10000 random numbers. Looks OK in theory? except none of the tests ever run. Testing com.cryptovide.miscTest Ran 23 tests containing 34 assertions. 0 failures, 0 errors. why don't the tests run? what can I do to make them run?

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  • How to maintain ComboBox.SelectedItem reference when DataSource is resorted?

    - by Dave
    This really seems like a bug to me, but perhaps some databinding gurus can enlighten me? (My WinForms databinding knowledge is quite limited.) I have a ComboBox bound to a sorted DataView. When the properties of the items in the DataView change such that items are resorted, the SelectedItem in my ComboBox does not keep in-sync. It seems to point to someplace completely random. Is this a bug, or am I missing something in my databinding? Here is a sample application that reproduces the problem. All you need is a Button and a ComboBox: public partial class Form1 : Form { private DataTable myData; public Form1() { this.InitializeComponent(); this.myData = new DataTable(); this.myData.Columns.Add("ID", typeof(int)); this.myData.Columns.Add("Name", typeof(string)); this.myData.Columns.Add("LastModified", typeof(DateTime)); this.myData.Rows.Add(1, "first", DateTime.Now.AddMinutes(-2)); this.myData.Rows.Add(2, "second", DateTime.Now.AddMinutes(-1)); this.myData.Rows.Add(3, "third", DateTime.Now); this.myData.DefaultView.Sort = "LastModified DESC"; this.comboBox1.DataSource = this.myData.DefaultView; this.comboBox1.ValueMember = "ID"; this.comboBox1.DisplayMember = "Name"; } private void saveStuffButton_Click(object sender, EventArgs e) { DataRowView preUpdateSelectedItem = (DataRowView)this.comboBox1.SelectedItem; // OUTPUT: SelectedIndex = 0; SelectedItem.Name = third Debug.WriteLine(string.Format("SelectedIndex = {0:N0}; SelectedItem.Name = {1}", this.comboBox1.SelectedIndex, preUpdateSelectedItem["Name"])); this.myData.Rows[0]["LastModified"] = DateTime.Now; DataRowView postUpdateSelectedItem = (DataRowView)this.comboBox1.SelectedItem; // OUTPUT: SelectedIndex = 2; SelectedItem.Name = second Debug.WriteLine(string.Format("SelectedIndex = {0:N0}; SelectedItem.Name = {1}", this.comboBox1.SelectedIndex, postUpdateSelectedItem["Name"])); // FAIL! Debug.Assert(object.ReferenceEquals(preUpdateSelectedItem, postUpdateSelectedItem)); } }

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  • Druapl & Regular PHP Integration

    - by user333128
    I'm building a new website which has one core application and many content pages. Content pages are mostly dynamic and I require a way to manage this dynamic content on a regular basis. The core application's main functionality is a 3 step process or reading user data (input page), reading data from MySQL (product page) and submitting an application to an email address (application page). Ideally I would like to build the core application in regular PHP and leverage Drupal for its content management capabilities. Can Drupal and regular PHP be integrated as I suggest easily? My feeling is that coding the core application as a Drupal module(s) will add layers of complexity that could be difficult to code from the outset and maintain later on as the system matures - so I would really like to just use regular PHP. Let me explain where dynamic content (managed by the CMS) intersects with the core application: Dynamic content such as FAQ data is used both on the 'normal' help pages and also within a mini-feed displayed within core application pages down a right hand side column. In this column, 3 random questions are pulled from the database and displayed as a feed. When users click on FAQ question they are not taken away from the core application product page but are instead shown data in a pop-up window displaying the question and answer. In addition, users can browse other questions and answers through a simple navigation menu within this popup. There are 3 such like feeds as I describe above that I require on the core application product page. So, what is the ideal solution here in terms of 'keeping things simple' for both the management of dynamic content and the ease of coding the core application? Can 'regular PHP' and Drupal co-exist 'peacefully'? If so, how is this technically possible? Because there is some content managed by Drupal contained within core application pages, can the core application still be coded in regular PHP? Any advice / suggestions? Thank you! Jim.

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  • Checking if an SSH tunnel is up and running

    - by Jarmund
    I have a perl script which, when destilled a bit, looks like this: my $randport = int(10000 + rand(1000)); # Random port as other scripts like this run at the same time my $localip = '192.168.100.' . ($port - 4000); # Don't ask... backwards compatibility system("ssh -NL $randport:$localip:23 root\@$ip -o ConnectTimeout=60 -i somekey &"); # create the tunnel in the background sleep 10; # Give the tunnel some time to come up # Create the telnet object my $telnet = new Net::Telnet( Timeout => 10, Host => 'localhost', Port => $randport, Telnetmode => 0, Errmode => \&fail, ); # SNIPPED... a bunch of parsing data from $telnet The thing is that the target $ip is on a link with very unpredictable bandwidth, so the tunnel might come up right away, it might take a while, it might not come up at all. So a sleep is necessary to give the tunnel some time to get up and running. So the question is: How can i test if the tunnel is up and running? 10 seconds is a really undesirable delay if the tunnel comes up straight away. Ideally, i would like to check if it's up and continue with creating the telnet object once it is, to a maximum of, say, 30 seconds.

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  • no more hitcollision at 1 life

    - by user1449547
    So I finally got my implementation of lives fixed, and it works. Now however when I collide with a ghost when I am at 1 life, nothing happens. I can fall to my death enough times for a game over. from what i can tell the problem is that hit collision is not longer working, because it does not detect a hit, I do not fall. the question is why? update if i kill myself fast enough it works, but if i play for like 30 seconds, it stops the hit collision detection on my ghosts. platforms and springs still work. public class World { public interface WorldListener { public void jump(); public void highJump(); public void hit(); public void coin(); public void dying(); } public static final float WORLD_WIDTH = 10; public static final float WORLD_HEIGHT = 15 * 20; public static final int WORLD_STATE_RUNNING = 0; public static final int WORLD_STATE_NEXT_LEVEL = 1; public static final int WORLD_STATE_GAME_OVER = 2; public static final Vector2 gravity = new Vector2(0, -12); public Hero hero; public final List<Platform> platforms; public final List<Spring> springs; public final List<Ghost> ghosts; public final List<Coin> coins; public Castle castle; public final WorldListener listener; public final Random rand; public float heightSoFar; public int score; public int state; public int lives=3; public World(WorldListener listener) { this.hero = new Hero(5, 1); this.platforms = new ArrayList<Platform>(); this.springs = new ArrayList<Spring>(); this.ghosts = new ArrayList<Ghost>(); this.coins = new ArrayList<Coin>(); this.listener = listener; rand = new Random(); generateLevel(); this.heightSoFar = 0; this.score = 0; this.state = WORLD_STATE_RUNNING; } private void generateLevel() { float y = Platform.PLATFORM_HEIGHT / 2; float maxJumpHeight = Hero.hero_JUMP_VELOCITY * Hero.hero_JUMP_VELOCITY / (2 * -gravity.y); while (y < WORLD_HEIGHT - WORLD_WIDTH / 2) { int type = rand.nextFloat() > 0.8f ? Platform.PLATFORM_TYPE_MOVING : Platform.PLATFORM_TYPE_STATIC; float x = rand.nextFloat() * (WORLD_WIDTH - Platform.PLATFORM_WIDTH) + Platform.PLATFORM_WIDTH / 2; Platform platform = new Platform(type, x, y); platforms.add(platform); if (rand.nextFloat() > 0.9f && type != Platform.PLATFORM_TYPE_MOVING) { Spring spring = new Spring(platform.position.x, platform.position.y + Platform.PLATFORM_HEIGHT / 2 + Spring.SPRING_HEIGHT / 2); springs.add(spring); } if (rand.nextFloat() > 0.7f) { Ghost ghost = new Ghost(platform.position.x + rand.nextFloat(), platform.position.y + Ghost.GHOST_HEIGHT + rand.nextFloat() * 3); ghosts.add(ghost); } if (rand.nextFloat() > 0.6f) { Coin coin = new Coin(platform.position.x + rand.nextFloat(), platform.position.y + Coin.COIN_HEIGHT + rand.nextFloat() * 3); coins.add(coin); } y += (maxJumpHeight - 0.5f); y -= rand.nextFloat() * (maxJumpHeight / 3); } castle = new Castle(WORLD_WIDTH / 2, y); } public void update(float deltaTime, float accelX) { updatehero(deltaTime, accelX); updatePlatforms(deltaTime); updateGhosts(deltaTime); updateCoins(deltaTime); if (hero.state != Hero.hero_STATE_HIT) checkCollisions(); checkGameOver(); checkFall(); } private void updatehero(float deltaTime, float accelX) { if (hero.state != Hero.hero_STATE_HIT && hero.position.y <= 0.5f) hero.hitPlatform(); if (hero.state != Hero.hero_STATE_HIT) hero.velocity.x = -accelX / 10 * Hero.hero_MOVE_VELOCITY; hero.update(deltaTime); heightSoFar = Math.max(hero.position.y, heightSoFar); } private void updatePlatforms(float deltaTime) { int len = platforms.size(); for (int i = 0; i < len; i++) { Platform platform = platforms.get(i); platform.update(deltaTime); if (platform.state == Platform.PLATFORM_STATE_PULVERIZING && platform.stateTime > Platform.PLATFORM_PULVERIZE_TIME) { platforms.remove(platform); len = platforms.size(); } } } private void updateGhosts(float deltaTime) { int len = ghosts.size(); for (int i = 0; i < len; i++) { Ghost ghost = ghosts.get(i); ghost.update(deltaTime); if (ghost.state == Ghost.GHOST_STATE_DYING && ghost.stateTime > Ghost.GHOST_DYING_TIME) { ghosts.remove(ghost); len = ghosts.size(); } } } private void updateCoins(float deltaTime) { int len = coins.size(); for (int i = 0; i < len; i++) { Coin coin = coins.get(i); coin.update(deltaTime); } } private void checkCollisions() { checkPlatformCollisions(); checkGhostCollisions(); checkItemCollisions(); checkCastleCollisions(); } private void checkPlatformCollisions() { if (hero.velocity.y > 0) return; int len = platforms.size(); for (int i = 0; i < len; i++) { Platform platform = platforms.get(i); if (hero.position.y > platform.position.y) { if (OverlapTester .overlapRectangles(hero.bounds, platform.bounds)) { hero.hitPlatform(); listener.jump(); if (rand.nextFloat() > 0.5f) { platform.pulverize(); } break; } } } } private void checkGhostCollisions() { int len = ghosts.size(); for (int i = 0; i < len; i++) { Ghost ghost = ghosts.get(i); if (hero.position.y < ghost.position.y) { if (OverlapTester.overlapRectangles(ghost.bounds, hero.bounds)){ hero.hitGhost(); listener.hit(); } break; } else { if(hero.position.y > ghost.position.y) { if (OverlapTester.overlapRectangles(hero.bounds, ghost.bounds)){ hero.hitGhostJump(); listener.jump(); ghost.dying(); score += Ghost.GHOST_SCORE; } break; } } } } private void checkItemCollisions() { int len = coins.size(); for (int i = 0; i < len; i++) { Coin coin = coins.get(i); if (OverlapTester.overlapRectangles(hero.bounds, coin.bounds)) { coins.remove(coin); len = coins.size(); listener.coin(); score += Coin.COIN_SCORE; } } if (hero.velocity.y > 0) return; len = springs.size(); for (int i = 0; i < len; i++) { Spring spring = springs.get(i); if (hero.position.y > spring.position.y) { if (OverlapTester.overlapRectangles(hero.bounds, spring.bounds)) { hero.hitSpring(); listener.highJump(); } } } } private void checkCastleCollisions() { if (OverlapTester.overlapRectangles(castle.bounds, hero.bounds)) { state = WORLD_STATE_NEXT_LEVEL; } } private void checkFall() { if (heightSoFar - 7.5f > hero.position.y) { --lives; hero.hitSpring(); listener.highJump(); } } private void checkGameOver() { if (lives<=0) { state = WORLD_STATE_GAME_OVER; } } }

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  • Django Interrupted system call when sending email

    - by mhost
    Hi, Sometimes, when submitting a form (pretty much any form on my site that sends me an email), I get the following error: File "/usr/lib/python2.5/smtplib.py", line 603, in starttls (resp, reply) = self.docmd("STARTTLS") File "/usr/lib/python2.5/smtplib.py", line 378, in docmd return self.getreply() File "/usr/lib/python2.5/smtplib.py", line 352, in getreply line = self.file.readline() File "/usr/lib/python2.5/socket.py", line 381, in readline data = self._sock.recv(self._rbufsize) error: (4, 'Interrupted system call') My code is sending email via gmail. I am also using django contact-form which does the same thing. The problem doesn't always happen. It seems very random. At one point today it got so bad that it displayed the error every time I submitted a form. Restarting apache fixes the problem for one submission and then it does it again. I have checked the RAM and there is plenty available (about 350MB available). Can someone lead me in the right direction? What does this error mean? What can I do to prevent this. Thanks.

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  • On Disk Substring index

    - by emeryc
    I have a file (fasta file to be specific) that I would like to index, so that I can quickly locate any substring within the file and then find the location within the original fasta file. This would be easy to do in many cases, using a Trie or substring array, unfortunately the strings I need to index are 800+ MBs which means that doing them in memory in unacceptable, so I'm looking for a reasonable way to create this index on disk, with minimal memory usage. (edit for clarification) I am only interested in the headers of proteins, so for the largest database I'm interested in, this is about 800 MBs of text. I would like to be able to find an exact substring within O(N) time based on the input string. This must be useable on 32 bit machines as it will be shipped to random people, who are not expected to have 64 bit machines. I want to be able to index against any word break within a line, to the end of the line (though lines can be several MBs long). Hopefully this clarifies what is needed and why the current solutions given are not illuminating. I should also add that this needs to be done from within java, and must be done on client computers on various operating systems, so I can't use any OS Specific solution, and it must be a programatic solution.

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  • Is it "right" to translate error messages?

    - by Iraklis
    This is somehow subjective depending on the target translation language, but bear with me for a sec. I have recently been involved in a translation project. The goal was to translate the strings of an MVC framework to the Greek language. 70% of the language strings of the framework where translated, however 30% where intentionally left out. The decision was that we will not translate error messages aimed towards the developer of the application. The reasoning behind this (in short) was: are aimed towards designers/programmers. Programmers ( and even designers :) ) should have a basic understanding of English, at least enough so they can search on it on Google if they do not know what it means. (racist?) are aimed towards the developer and in a perfect world should not be displayed to the end user of the application as they concern the inner workings of the web application itself. i.e "You must set the database name in your database config file." and perhaps most importantly, they make the life of the developer harder when he tries to get more information/help regarding the error. For example the above error yields 8 results in Google (in quotes), whereas its Greek translation yields exactly 0. I know that this depends on the popularity of the target translation language and the application itself. For example I'm guessing that there are is vast amount of documentation regarding German SAP error messages (i know, i know, SAP IS German, but you get the point), as opposed to Greek Error Messages documentation regarding random application X which has about 500 installations worldwide. So to summarize: When you develop language translation packs for your applications do you translate error messages? Do you only do for predominant languages like English/Spanish/German/French? Or do you live them intact? I'm not looking for the "right" or "correct" answer, I'm looking for a "best-practices" answer, or if this problem is defined in any "official" standard/policy that you have had experience with.

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  • [FIXED] Scan file contents into an array of a structure.

    - by ZaZu
    Hello, I have a structure in my program that contains a particular array. I want to scan a random file with numbers and put the contents into that array. This is my code : ( NOTE : This is a sample from a bigger program, so I need the structure and arrays as declared ) The contents of the file are basically : 5 4 3 2 5 3 4 2 #include<stdio.h> #define first 500 #define sec 500 struct trial{ int f; int r; float what[first][sec]; }; int trialtest(trial *test); main(){ trial test; trialtest(&test); } int trialtest(trial *test){ int z,x,i; FILE *fin; fin=fopen("randomfile.txt","r"); for(i=0;i<5;i++){ fscanf(fin,"%5.2f\t",(*test).what[z][x]); } fclose(fin); return 0; } But the problem is, whenever this I run this code, I get this error : (25) : warning 508 - Data of type 'double' supplied where a pointer is required I tried adding do{ for(i=0;i<5;i++){ q=fscanf(fin,"%5.2f\t",(*test).what[z][x]); } }while(q!=EOF); But that didnt work either, it gives the same error. Does anyone have a solution to this problem ?

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  • How to create C++ istringstream from a char array with null(0) characters?

    - by Morpheus
    I have a char array which contains null characters at random locations. I tried to create an iStringStream using this array (encodedData_arr) as below, I use this iStringStream to insert binary data(imagedata of Iplimage) to a MySQL database blob field(using MySQL Connector/C++'s setBlob(istream *is) ) it only stores the characters upto the first null character. Is there a way to create an iStringStream using a char array with null characters? unsigned char *encodedData_arr = new unsigned char[data_vector_uchar->size()]; // Assign the data of vector<unsigned char> to the encodedData_arr for (int i = 0; i < vec_size; ++i) { cout<< data_vector_uchar->at(i)<< " : "<< encodedData_arr[i]<<endl; } // Here the content of the encodedData_arr is same as the data_vector_uchar // So char array is initializing fine. istream *is = new istringstream((char*)encodedData_arr, istringstream::in || istringstream::binary); prepStmt_insertImage->setBlob(1, is); // Here only part of the data is stored in the database blob field (Upto the first null character)

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  • Stop Visual Studio from appending numbers to the end of new controls

    - by techturtle
    I am wondering if there is any way to stop Visual Studio 2010 from appending a number to the end of the ID on new controls I create. For example, when I add a new TextBox, I would prefer that it do this: <asp:TextBox ID="TextBox" runat="server"> <asp:TextBox ID="TextBox" runat="server"> <asp:TextBox ID="TextBox" runat="server"> Instead of this: <asp:TextBox ID="TextBox1" runat="server"> <asp:TextBox ID="TextBox2" runat="server"> <asp:TextBox ID="TextBox3" runat="server"> It would make it easier to rename them appropriately, so I don't have to arrow/mouse over and delete the number each time. As I was writing this, the "Questions that may already have your answer" suggested this: How do I prevent Visual Studio from renaming my controls? which admittedly was the biggest part of my annoyance, but that appears to turn off putting in an ID="" field altogether, not just for pasted controls. It would still be helpful to turn off the numbering for new, non-pasted controls and have it not rename pasted ones as well. At the moment I'm working with ASP.NET, but it would be nice if it there was a way to do it for WinForms as well. Before anyone suggests it, I do know that allowing it to append the numbers prevents name conflicts should I not rename them appropriately. However, I would much rather have it fail to compile so I know to fix the issue now (if I forget to name something properly) rather than find random "TextBox1" items lying around in the code later on.

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  • Display two array's in the same table

    - by Naeem Ahmed
    $row = $query->fetchAll(PDO::FETCH_ASSOC); $num_rows = count($row); for ($i = 0; $i < $num_rows; $i++) { $title = htmlspecialchars($row[$i]['title']); $author =htmlspecialchars($row[$i]['author']); $school =htmlspecialchars($row[$i]['school']); $solution = $row[$i]['solution']; $notes = $row[$i]['notes']; $ad = array($title, $price, $author, $school, $contact, $content, $date); $inlcude = array($solutions, $notes); $field = 0; echo "<table border='1'>"; // foreach($inlcude as $in) This failled miserably foreach ($ad as $post) { if ($field < 3) //The first three values are placed in the first row { echo "<td>$post</td>"; } if ($field >= 3) { echo "<tr><td>$post</td><td>$in</td></tr>"; } $field++; } echo '</table>'; } I have two arrays and I would like to display them in different columns in my table. $ad displays perfectly fine but I'm having trouble displaying the contents in $inlcude in the second column. I've tried putting another foreach loop to iterate through contents of the second array but that really screws up my table by placing random values in different places on the table. Besides the foreach loop, I don't know of any other way to iterate through the array. Any suggestions would be appreciated.Thanks!

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  • Why do Scala maps have poor performance relative to Java?

    - by Mike Hanafey
    I am working on a Scala app that consumes large amounts of CPU time, so performance matters. The prototype of the system was written in Python, and performance was unacceptable. The application does a lot with inserting and manipulating data in maps. Rex Kerr's Thyme was used to look at the performance of updating and retrieving data from maps. Basically "n" random Ints were stored in maps, and retrieved from the maps, with the time relative to java.util.HashMap used as a reference. The full results for a range of "n" are here. Sample (n=100,000) performance relative to java, smaller is worse: Update Read Mutable 16.06% 76.51% Immutable 31.30% 20.68% I do not understand why the scala immutable map beats the scala mutable map in update performance. Using the sizeHint on the mutable map does not help (it appears to be ignored in the tested implementation, 2.10.3). Even more surprisingly the immutable read performance is worse than the mutable read performance, more significantly so with larger maps. The update performance of the scala mutable map is surprisingly bad, relative to both scala immutable and plain Java. What is the explanation?

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  • When should EntityManagerFactory instance be created/opened ?

    - by masato-san
    Ok, I read bunch of articles/examples how to write Entity Manager Factory in singleton. One of them easiest for me to understand a bit: http://javanotepad.blogspot.com/2007/05/jpa-entitymanagerfactory-in-web.html I learned that EntityManagerFactory (EMF) should only be created once preferably in application scope. And also make sure to close the EMF once it's used (?) So I wrote EMF helper class for business methods to use: public class EmProvider { private static final String DB_PU = "KogaAlphaPU"; public static final boolean DEBUG = true; private static final EmProvider singleton = new EmProvider(); private EntityManagerFactory emf; private EmProvider() {} public static EmProvider getInstance() { return singleton; } public EntityManagerFactory getEntityManagerFactory() { if(emf == null) { emf = Persistence.createEntityManagerFactory(DB_PU); } if(DEBUG) { System.out.println("factory created on: " + new Date()); } return emf; } public void closeEmf() { if(emf.isOpen() || emf != null) { emf.close(); } emf = null; if(DEBUG) { System.out.println("EMF closed at: " + new Date()); } } }//end class And my method using EmProvider: public String foo() { EntityManager em = null; List<Object[]> out = null; try { em = EmProvider.getInstance().getEntityManagerFactory().createEntityManager(); Query query = em.createNativeQuery(JPQL_JOIN); //just some random query out = query.getResultList(); } catch(Exception e) { //handle error.... } finally { if(em != null) { em.close(); //make sure to close EntityManager } } I made sure to close EntityManager (em) within method level as suggested. But when should EntityManagerFactory be closed then? And why EMF has to be singleton so bad??? I read about concurrency issues but as I am not experienced multi-thread-grammer, I can't really be clear on this idea.

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  • What are these stray zero-byte files extracted from tarball? (OSX)

    - by Scott M
    I'm extracting a folder from a tarball, and I see these zero-byte files showing up in the result (where they are not in the source.) Setup (all on OS X): On machine one, I have a directory /My/Stuff/Goes/Here/ containing several hundred files. I build it like this tar -cZf mystuff.tgz /My/Stuff/Goes/Here/ On machine two, I scp the tgz file to my local directory, then unpack it. tar -xZf mystuff.tgz It creates ~scott/My/Stuff/Goes/, but then under Goes, I see two files: Here/ - a directory, Here.bGd - a zero byte file. The "Here.bGd" zero-byte file has a random 3-character suffix, mixed upper and lower-case characters. It has the same name as the lowest-level directory mentioned in the tar-creation command. It only appears at the lowest level directory named. Anybody know where these come from, and how I can adjust my tar creation to get rid of them? Update: I checked the table of contents on the files using tar tZvf: toc does not list the zero-byte files, so I'm leaning toward the suggestion that the uncompress machine is at fault. OS X is version 10.5.5 on the unzip machine (not sure how to check the filesystem type). Tar is GNU tar 1.15.1, and it came with the machine.

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  • C# Recursion SumOfOnlyNeg Elements

    - by Chris
    Hello, A array gets filled up with random elements (negative and positive). Now i want to calculate the sum of ONLY the postive elements. Iterative there is no problem, but in the recursion version i can only get the sum of both negative and postive. How can i "check" in the recursive version that it only sums up the Postive elements? Best Regards. Iterative version: public int IterSomPosElem(int[] tabel, int n) { n = 0; for (int i = 0; i < tabel.Length; i++) { if (tabel[i] >= 0) { n += tabel[i]; } } return n; } Recursive version atm (sums up all the elements insteed, of only the positive) public int RecuSomPosElem(int[] tabel, int n) { if(n == 1) return tabel[0]; //stopCriterium else { return (tabel[n - 1] + RecuSomPosElem(tabel, n - 1)); // how to check, so it only sums up the postive elements and "ignores" the negative elements. } }

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  • Hibernate Transient Extends problem

    - by mrvreddy
    @MappedSuperclass public abstract class BaseAbstract implements Serializable{ private static final long serialVersionUID = 1L; protected String test = //some random value; public String getTest() { return test; } public void setTest(String test){ this.test = test; } } @Entity public class Artist extends BaseAbstract { private static final long serialVersionUID = 1L; private Integer id; @override @Transient public String getTest() { return test; } ..... } My question is... when i am trying to do any operation on the artist, along with id and name, test is also getting saved which should not be the case... if i add the same transient on the baseabstract class getTest() method, i see test column NOT getting created(ideally what it should happen) but if i try to override the method with adding annotaion in the sub class it creates the test column... I dont know why this is happening since when hibernate is creating the artist object and checks for annotations, it should see the transient annotation present on the getTest() of artist method...and should not create a column in the database... Let me know if you need any clarification.... Any response on this is greatly appreciated.... Thank you

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  • Am I encrypting my passwords correctly in ASP.NET

    - by Nick
    I have a security class: public class security { private static string createSalt(int size) { //Generate a random cryptographic number RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider(); byte[] b = new byte[size]; rng.GetBytes(b); //Convert to Base64 return Convert.ToBase64String(b); } /// <summary> /// Generate a hashed password for comparison or create a new one /// </summary> /// <param name="pwd">Users password</param> /// <returns></returns> public static string createPasswordHash(string pwd) { string salt = "(removed)"; string saltAndPwd = string.Concat(pwd, salt); string hashedPwd = FormsAuthentication.HashPasswordForStoringInConfigFile( saltAndPwd, "sha1"); return hashedPwd; } } This works fine, but I am wondering if it is sufficient enough. Also, is this next block of code better? Overkill? static byte[] encrInitVector = new byte[] { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF }; static string encrKey = "(removed)"; public static string EncryptString(string s) { byte[] key; try { key = Encoding.UTF8.GetBytes(encrKey.Substring(0, 8)); DESCryptoServiceProvider des = new DESCryptoServiceProvider(); byte[] inputByteArray = Encoding.UTF8.GetBytes(s); MemoryStream ms = new MemoryStream(); CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(key, encrInitVector), CryptoStreamMode.Write); cs.Write(inputByteArray, 0, inputByteArray.Length); cs.FlushFinalBlock(); return Convert.ToBase64String(ms.ToArray()); } catch (Exception e) { throw e; }

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  • C# Finding 2 positions 1-dimArray

    - by Chris
    Hello, In a method i am calculating the longest row of elements. The 1-dim array is filled up with random values (0 or 1). The method looks up the longest row (being 0 or 1, whatever is the longest). Meaning in for example: 1110100 --> the longest row would be 3 (3 * 1) 0110000 --> the longest row would be 4 (4 * 0) My problem is i am trying to perform some type of linear search to show the position of the row in the array. The first example has the longest row of 3 elements (3 times 1). For 1110100 the position in the array would be 0 - 2 (index) For 0110000 the position in the array would be 3 - 6 (index) I have been trying with foreaches, for loops etc..but i cannot seem to get the proper indexes of both. Cannot seem to display both positions properly. For the first example the correct output wouldbe: The largest row of same elements of the array consists of 3 elements on the position 0 - 2. The longest row of elements gets of same elements get calculated as the following: public int BerekenDeelrij (int [] table) ( int count = 0; final int value = 0; int largest = 0; foreach (int value in table) ( if (value == last value) counter + +; else ( largest = Math.Max largest (largest, counter); final value = value count = 1; ) ) Math.Max return (largest, counter); ) Best Regards.

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  • ActionListener isn't Implementing

    - by Nick Gibson
    JFrameWithPanel is not abstract and does not override abstract method actionPerformed(java.awt.event.ActionEvent) in java.awt.event.ActionListener public class JFrameWithPanel extends JFrame implements ActionListener I Don't get this code. Book and Java site tells me this is the syntax for the method, but again this error shows up constantly. import javax.swing.*; import javax.swing.JOptionPane; import java.awt.*; import java.awt.event.*; import java.lang.Math.*; import java.lang.Integer.*; import java.util.*; import java.util.Random; import java.io.*; import java.text.*; import java.text.DecimalFormat.*; public class JFrameWithPanel extends JFrame implements ActionListener { JButton button = new JButton("Exit"); public JFrameWithPanel() { super("JFrame with Panel"); JComboBox packageChoice = new JComboBox(); packageChoice.addItem("A+ Certification"); packageChoice.addItem("Network+ Certification "); packageChoice.addItem("Security+ Certifictation"); packageChoice.addItem("CIT Full Test Package"); packageChoice.addActionListener(this); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JPanel pane = new JPanel(); pane.add(button); pane.add(packageChoice); setContentPane(pane); setSize(200,100); setVisible(true); } } then later public class CreateJFrameWithPanel { public static void main(String[] args) { JFrameWithPanel panel = new JFrameWithPanel(); } }

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  • Javascript Recursion

    - by rpophessagr
    I have an ajax call and would like to recall it once I finish parsing and animating the result into the page. And that's where I'm getting stuck. I was able to recall the function, but it seems to not take into account the delays in the animation. i.e. The console keeps outputting the values at a wild pace. I thought setInterval might help with the interval being the sum of the length of my delays, but I can't get that to work... function loadEm(){ var result=new Array(); $.getJSON("jsonCall.php",function(results){ $.each(results, function(i, res){ rand = (Math.floor(Math.random()*11)*1000)+2000; fullRand += rand; console.log(fullRand); $("tr:first").delay(rand).queue(function(next) { doStuff(res); next(); }); }); var int=self.setInterval("loadEm()",fullRand); }); } });

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  • My python program always brings down my internet connection after several hours running, how do I debug and fix this problem?

    - by Shane
    I'm writing a python script checking/monitoring several server/websites status(response time and similar stuff), it's a GUI program and I use separate thread to check different server/website, and the basic structure of each thread is using an infinite while loop to request that site every random time period(15 to 30 seconds), once there's changes in website/server each thread will start a new thread to do a thorough check(requesting more pages and similar stuff). The problem is, my internet connection always got blocked/jammed/messed up after several hours running of this script, the situation is, from my script side I got urlopen error timed out each time it's requesting a page, and from my FireFox browser side I cannot open any site. But the weird thing is, the moment I close my script my Internet connection got back on immediately which means now I can surf any site through my browser, so it must be the script causing all the problem. I've checked the program carefully and even use del to delete any connection once it's used, still get the same problem. I only use urllib2, urllib, mechanize to do network requests. Anybody knows why such thing happens? How do I debug this problem? Is there a tool or something to check my network status once such situation occurs? It's really bugging me for a while... By the way I'm behind a VPN, does it have something to do with this problem? Although I don't think so because my network always get back on once the script closed, and the VPN connection never drops(as it appears) during the whole process.

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  • Compact data structure for storing a large set of integral values

    - by Odrade
    I'm working on an application that needs to pass around large sets of Int32 values. The sets are expected to contain ~1,000,000-50,000,000 items, where each item is a database key in the range 0-50,000,000. I expect distribution of ids in any given set to be effectively random over this range. The operations I need on the set are dirt simple: Add a new value Iterate over all of the values. There is a serious concern about the memory usage of these sets, so I'm looking for a data structure that can store the ids more efficiently than a simple List<int>or HashSet<int>. I've looked at BitArray, but that can be wasteful depending on how sparse the ids are. I've also considered a bitwise trie, but I'm unsure how to calculate the space efficiency of that solution for the expected data. A Bloom Filter would be great, if only I could tolerate the false negatives. I would appreciate any suggestions of data structures suitable for this purpose. I'm interested in both out-of-the-box and custom solutions. EDIT: To answer your questions: No, the items don't need to be sorted By "pass around" I mean both pass between methods and serialize and send over the wire. I clearly should have mentioned this. There could be a decent number of these sets in memory at once (~100).

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