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  • How do I get Mathematica to thread a 2-variable function over two lists, using functional programmin

    - by Leah Wrenn Berman
    Lets say I have a function f[x_, y_], and two lists l1, l2. I'd like to evaluate f[x,y] where x runs over the list l1 and y runs over the list l2, and I'd like to do it without having to make all pairs of the form {l1[[i]],l2[[j]]}. (Motivation: I'm trying to implement some basic Haskell programs in Mathematica. In particular, I'd like to be able to code the Haskell program isMatroid::[[Int]]->Bool isMatroid b =and[or[sort(union(xs\\[x])[y]'elem'b|y<-ys]|xs<-b,ys<-b, xs<-x] I think I can do the rest of it, if I can figure out the original question, but I'd like the code to be Haskell-like. Any suggestions for implementing Haskell-like code in Mathematica would be appreciated.)

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  • visual studio 2002: c# threading question

    - by dotnet-practitioner
    Hi, I have a piece of code where I send a file content over tcp/ip channel. There are times when this connection hangs causing entire application to freeze. Is there a way for my main thread to spawn a worker thread and monitor that worker thread. If worker thread succeeds, well and good. If it hangs , the main thread could log error message and continue. How can I simulate in my test code that a worker thread is hanging. please let me know what could the code look like. I am using C# Visual studio 2002.

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  • how to execute two thread simultaneously in java swing?

    - by jcrshankar
    My aim is to select all the files named with MANI.txt which is present in their respective folders and then load path of the MANI.txt files different location in table. After I load the path in the table,I used to select needed path and modifiying those. To load the MANI.txt files taking more time,because it may present more than 30 times in my workspace or etc. until load the files I want to give alarm to the user with help of ProgessBar.Once the list size has been populated I need to disable ProgressBar. Could anyone please help me out on this? import java.awt.*; import javax.swing.*; import javax.swing.table.*; import java.awt.event.*; import java.io.BufferedReader; import java.io.File; import java.io.FileNotFoundException; import java.io.FileReader; import java.io.FileWriter; import java.io.IOException; import java.io.PrintWriter; public class JTableHeaderCheckBox extends JFrame implements ActionListener { Object colNames[] = {"", "Path"}; Object[][] data = {}; DefaultTableModel dtm; JTable table; JButton but; java.util.List list; public void buildGUI() { dtm = new DefaultTableModel(data,colNames); table = new JTable(dtm); table.setAutoResizeMode(JTable.AUTO_RESIZE_OFF); int vColIndex = 0; TableColumn col = table.getColumnModel().getColumn(vColIndex); int width = 10; col.setPreferredWidth(width); int vColIndex1 = 1; TableColumn col1 = table.getColumnModel().getColumn(vColIndex1); int width1 = 500; col1.setPreferredWidth(width1); JFileChooser chooser = new JFileChooser(); //chooser.setCurrentDirectory(new java.io.File(".")); chooser.setDialogTitle("Choose workSpace Path"); chooser.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY); chooser.setAcceptAllFileFilterUsed(false); if (chooser.showOpenDialog(this) == JFileChooser.APPROVE_OPTION){ System.out.println("getCurrentDirectory(): " + chooser.getCurrentDirectory()); System.out.println("getSelectedFile() : " + chooser.getSelectedFile().getAbsolutePath()); } String path= chooser.getSelectedFile().getAbsolutePath(); File folder = new File(path); Here I need progress bar GatheringFiles ob = new GatheringFiles(); list=ob.returnlist(folder); for(int x = 0; x < list.size(); x++) { dtm.addRow(new Object[]{new Boolean(false),list.get(x).toString()}); } JPanel pan = new JPanel(); JScrollPane sp = new JScrollPane(table); TableColumn tc = table.getColumnModel().getColumn(0); tc.setCellEditor(table.getDefaultEditor(Boolean.class)); tc.setCellRenderer(table.getDefaultRenderer(Boolean.class)); tc.setHeaderRenderer(new CheckBoxHeader(new MyItemListener())); but = new JButton("REMOVE"); JFrame f = new JFrame(); pan.add(sp); but.move(650, 50); but.addActionListener(this); pan.add(but); f.add(pan); f.setSize(700, 100); f.pack(); f.setLocationRelativeTo(null); f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); f.setVisible(true); } class MyItemListener implements ItemListener { public void itemStateChanged(ItemEvent e) { Object source = e.getSource(); if (source instanceof AbstractButton == false) return; boolean checked = e.getStateChange() == ItemEvent.SELECTED; for(int x = 0, y = table.getRowCount(); x < y; x++) { table.setValueAt(new Boolean(checked),x,0); } } } public static void main (String[] args) { SwingUtilities.invokeLater(new Runnable(){ public void run(){ new JTableHeaderCheckBox().buildGUI(); } }); } public void actionPerformed(ActionEvent e) { // TODO Auto-generated method stub if(e.getSource()==but) { System.err.println("table.getRowCount()"+table.getRowCount()); for(int x = 0, y = table.getRowCount(); x < y; x++) { if("true".equals(table.getValueAt(x, 0).toString())) { System.err.println(table.getValueAt(x, 0)); System.err.println(list.get(x).toString()); delete(list.get(x).toString()); } } } } public void delete(String a) { String delete = "C:"; System.err.println(a); try { File inFile = new File(a); if (!inFile.isFile()) { System.out.println("Parameter is not an existing file"); return; } //Construct the new file that will later be renamed to the original filename. File tempFile = new File(inFile.getAbsolutePath() + ".tmp"); BufferedReader br = new BufferedReader(new FileReader(inFile)); PrintWriter pw = new PrintWriter(new FileWriter(tempFile)); String line = null; //Read from the original file and write to the new //unless content matches data to be removed. while ((line = br.readLine()) != null) { System.err.println(line); line = line.replace(delete, " "); pw.println(line); pw.flush(); } pw.close(); br.close(); //Delete the original file if (!inFile.delete()) { System.out.println("Could not delete file"); return; } //Rename the new file to the filename the original file had. if (!tempFile.renameTo(inFile)) System.out.println("Could not rename file"); } catch (FileNotFoundException ex) { ex.printStackTrace(); } catch (IOException ex) { ex.printStackTrace(); } } } class CheckBoxHeader extends JCheckBox implements TableCellRenderer, MouseListener { protected CheckBoxHeader rendererComponent; protected int column; protected boolean mousePressed = false; public CheckBoxHeader(ItemListener itemListener) { rendererComponent = this; rendererComponent.addItemListener(itemListener); } public Component getTableCellRendererComponent( JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) { if (table != null) { JTableHeader header = table.getTableHeader(); if (header != null) { rendererComponent.setForeground(header.getForeground()); rendererComponent.setBackground(header.getBackground()); rendererComponent.setFont(header.getFont()); header.addMouseListener(rendererComponent); } } setColumn(column); rendererComponent.setText("Check All"); setBorder(UIManager.getBorder("TableHeader.cellBorder")); return rendererComponent; } protected void setColumn(int column) { this.column = column; } public int getColumn() { return column; } protected void handleClickEvent(MouseEvent e) { if (mousePressed) { mousePressed=false; JTableHeader header = (JTableHeader)(e.getSource()); JTable tableView = header.getTable(); TableColumnModel columnModel = tableView.getColumnModel(); int viewColumn = columnModel.getColumnIndexAtX(e.getX()); int column = tableView.convertColumnIndexToModel(viewColumn); if (viewColumn == this.column && e.getClickCount() == 1 && column != -1) { doClick(); } } } public void mouseClicked(MouseEvent e) { handleClickEvent(e); ((JTableHeader)e.getSource()).repaint(); } public void mousePressed(MouseEvent e) { mousePressed = true; } public void mouseReleased(MouseEvent e) { } public void mouseEntered(MouseEvent e) { } public void mouseExited(MouseEvent e) { } } ****************** import java.io.File; import java.util.*; public class GatheringFiles { public static List returnlist(File folder) { List<File> list = new ArrayList<File>(); List<File> list1 = new ArrayList<File>(); getFiles(folder, list); return list; } private static void getFiles(File folder, List<File> list) { folder.setReadOnly(); File[] files = folder.listFiles(); for(int j = 0; j < files.length; j++) { if( "MANI.txt".equals(files[j].getName())) { list.add(files[j]); } if(files[j].isDirectory()) getFiles(files[j], list); } } }

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  • Can I Always debug multiple instances of a same object that is of type thread with GDB?

    - by yan bellavance
    program runs fine. When I put a breakpoint a segmentation fault is generated. Is it me or GDB? At run time this never happens and if I instantiate only one object then no problems. Im using QtCreator on ubuntu x86_64 karmic koala. UPDATE1: I have made a small program containing a simplified version of that class. You can download it at: example program simply put a breakpoint on the first line of the function called drawChart() and step into to see the segfault happen UPDATE2: This is another small program but it is practically the same as the mandlebrot example and it is still happening. You can diff it with mandlebrot to see the small difference. almost the same as mandlebrot example program

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  • WPF windows locked when calling webservice. Even when run asynchronously

    - by SumGuy
    Hi there. I'm having a big problem when calling a web service from my WPF application. The application/window locks until the process has completed. I've attempted to run this asynchronously but the problem still persists. Currently, the web service call I'm making can last 45-60 seconds. It runs a process on the server to fetch a big chunk of data. As it take a little while I wanted to have a progress bar moving indeterminately for the user to see that the application hasn't stalled or anything (you know how impatatient they get). So: private void btnSelect_Click(object sender, RoutedEventArgs e) { wDrawingList = new WindowDrawingList(systemManager); AsyncMethodHandler caller = default(AsyncMethodHandler); caller = new AsyncMethodHandler(setupDrawingList); // open new thread with callback method caller.BeginInvoke((Guid)((Button)sender).Tag, MyAsyncCallback, null); } Click a button and the app will create the form that the async stuff will be posted to and set up the async stuff calling the async method. public bool setupDrawingList(Guid ID) { if (systemManager.set(ID)) { wDrawingList.Dispatcher.Invoke(DispatcherPriority.Background, new Action(() => { wDrawingList.ShowForm(); Hide(); })); return true; } return false; } This is the async method. The showForm method contains the calls to setup the new form including the monster web service call public void MyAsyncCallback(IAsyncResult ar) { // Because you passed your original delegate in the asyncState parameter of the Begin call, you can get it back here to complete the call. MethodDelegate dlgt = (MethodDelegate)ar.AsyncState; // Complete the call. bool output = dlgt.EndInvoke(ar); try { // Retrieve the delegate. AsyncResult result = (AsyncResult)ar; AsyncMethodHandler caller = (AsyncMethodHandler)result.AsyncDelegate; // Because this method is running from secondary thread it can never access ui objects because they are created // on the primary thread. // Call EndInvoke to retrieve the results. bool returnValue = caller.EndInvoke(ar); // Still on secondary thread, must update ui on primary thread UpdateUI(returnValue == true ? "Success" : "Failed"); } catch (Exception ex) { string exMessage = null; exMessage = "Error: " + ex.Message; UpdateUI(exMessage); } } public void UpdateUI(string outputValue) { // Get back to primary thread to update ui UpdateUIHandler uiHandler = new UpdateUIHandler(UpdateUIIndicators); string results = outputValue; // Run new thread off Dispatched (primary thread) this.Dispatcher.Invoke(System.Windows.Threading.DispatcherPriority.Normal, uiHandler, results); } public void UpdateUIIndicators(string outputValue) { // update user interface controls from primary UI thread sbi3.Content = "Processing Completed."; } Any help or theories are appreciated. I'm at a loss. Thanks in advance

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  • search engine (solr/sphinx) question

    - by noname
    i want to make my threads content searchable with full text search engines like solr. but i wonder one thing. should i index just the thread.title, thread.body and post.body or should i index username, created date, nr of posts, views, country, region and city too that belongs to thread? i mean when an user search for a thread he will get hits returned containing thread title, 2 lines of body, which user has posted it, creation date, tags, and so on. should i index all this information too? but then it would be pretty much the whole database. or should i just index the 3 first columns i mentioned for full text search. and another question. when an user post a new thread, then i have to immidiately tell solr to add that row? if im not, how would it be searchable?

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  • How to signal a buffer full state between posix threads

    - by mikip
    Hi I have two threads, the main thread 'A' is responsible for message handling between a number of processes. When thread A gets a buffer full message, it should inform thread B and pass a pointer to the buffer which thread B will then process. When thread B has finished it should inform thread A that it has finished. How do I go about implementing this using posix threads using C on linux. I have looked at conditional variables, is this the way to go? . I'm not experienced in multi threaded programming and would like some advice on the best avenue to take. Thanks

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  • Multi-threaded Pooled Allocators

    - by Darren Engwirda
    I'm having some issues using pooled memory allocators for std::list objects in a multi-threaded application. The part of the code I'm concerned with runs each thread function in isolation (i.e. there is no communication or synchronization between threads) and therefore I'd like to setup separate memory pools for each thread, where each pool is not thread-safe (and hence fast). I've tried using a shared thread-safe singleton memory pool and found the performance to be poor, as expected. This is a heavily simplified version of the type of thing I'm trying to do. A lot has been included in a pseudo-code kind of way, sorry if it's confusing. /* The thread functor - one instance of MAKE_QUADTREE created for each thread */ class make_quadtree { private: /* A non-thread-safe memory pool for int linked list items, let's say that it's * something along the lines of BOOST::OBJECT_POOL */ pooled_allocator<int> item_pool; /* The problem! - a local class that would be constructed within each std::list as the * allocator but really just delegates to ITEM_POOL */ class local_alloc { public : //!! I understand that I can't access ITEM_POOL from within a nested class like //!! this, that's really my question - can I get something along these lines to //!! work?? pointer allocate (size_t n) { return ( item_pool.allocate(n) ); } }; public : make_quadtree (): item_pool() // only construct 1 instance of ITEM_POOL per // MAKE_QUADTREE object { /* The kind of data structures - vectors of linked lists * The idea is that all of the linked lists should share a local pooled allocator */ std::vector<std::list<int, local_alloc>> lists; /* The actual operations - too complicated to show, but in general: * * - The vector LISTS is grown as a quadtree is built, it's size is the number of * quadtree "boxes" * * - Each element of LISTS (each linked list) represents the ID's of items * contained within each quadtree box (say they're xy points), as the quadtree * is grown a lot of ID pop/push-ing between lists occurs, hence the memory pool * is important for performance */ } }; So really my problem is that I'd like to have one memory pool instance per thread functor instance, but within each thread functor share the pool between multiple std::list objects.

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  • What is the "task" in twitter Storm parallelism

    - by John Wang
    I'm trying to learn twitter storm by following the great article "Understanding the parallelism of a Storm topology" However I'm a bit confused by the concept of "task". Is a task an running instance of the component(spout or bolt) ? A executor having multiple tasks actually is saying the same component is executed for multiple times by the executor, am I correct ? Moreover in a general parallelism sense, Storm will spawn a dedicated thread(executor) for a spout or bolt, but what is contributed to the parallelism by an executor(thread) having multiple tasks ? I think having multiple tasks in a thread, since a thread executes sequentially, only make the thread a kind of "cached" resource, which avoids spawning new thread for next task run. Am I correct? I may clear those confusion by myself after taking more time to investigate, but you know, we both love stackoverflow ;-) Thanks in advance.

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  • Can I find out which thread is running using Eclipse?

    - by Roman
    I close my application by pressing a "Close" button. But in the Eclipse I see a red square indicating that something is still running. When I press this red square, I kill my application completely. Is it possible to find out what is still running (which method, which loop) using Eclipse? P.S. I am a newbie. So, it would be nice to have a simple solution. I also might not understand your answer if you use "technical" words which I do not know.

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  • Best ASP.NET Background Service Implementation

    - by Jason N. Gaylord
    What's the best implementation for more than one background service in an ASP.NET application? Timer Callback Timer timer = new Timer(new TimerCallback(MyWorkCallback), HttpContext, 5000, 5000); Thread or ThreadPool Thread thread = new Thread(Work); thread.IsBackground = true; thread.Start(); BackgroundWorker BackgroundWorker worker = new BackgroundWorker(); worker.DoWork += new DoWorkEventHandler(DoMyWork); worker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(DoMyWork_Completed); worker.RunWorkerAsync(); Caching like http://www.codeproject.com/KB/aspnet/ASPNETService.aspx (located in Jeff Atwood's post here) I need to run multiple background "services" at a given time. One service may run every 5 minutes where another may be once a day. It will never be more than 10 services running at a time.

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  • How to tell which thread(s) are producing all the garbage?

    - by Brad Hein
    I have an app with about 15 threads. Most do mundane tasks and sleep most of their lives. Others collect information and cache it in hashmaps. The hashmaps grow to a moderate size and level out. The number of keys and size of value remains constant, but the contents of the values changes (at 33 keys per second average). When I start my app, I notice the garbage collection interval goes from minutes to once per second, and the amount of garbage is 700k+ each time. In fact as I was writing this, it caused my phone to reboot with an error "Referencetable Overflow". Here's my question: Are there any tricks to identifying which threads are producing the garbage, or even finding out more about what garbage they are producing?

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  • cannot read but can write on serial port through Android Emulator

    - by Aad
    I am working on a program that is communicating with serial port over USB through Android emulator. emulator -qemu -serial /dev/ttyUSB0 The emulator is able to open the port and write into it. However, read is not happening. The program has a timeout for read maintained by a timer. The read happens in a separate 'read' thread. The main thread has a socketpair fd pair to signal the read-thread that the serial port is closed post timeout. In the read-thread, polling happens(poll() function call) over the 2 file-descriptors: one is serial port fd, the other is one of the socketpair. The board that I have connected to works fine with sending commands over 'cutecom' The poll never succeeds for serial port. However, poll succeeds for 'socketpair'ed fd and the thread ends on a close-signal sent from main-thread post timeout. Ouestions: Are there any special settings for read as even loop-back fails Are there differences between settings for read and write on a serial port?

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  • breaking out from socket select

    - by kamziro
    I have a loop which basically calls this every few seconds (after the timeout): while(true){ if(finished) return; switch(select(FD_SETSIZE, &readfds, 0, 0, &tv)){ case SOCKET_ERROR : report bad stuff etc; return; default : break; } // do stuff with the incoming connection } So basically for every few seconds (which is specified by tv), it reactivates the listening. This is run on thread B (not a main thread). There are times when I want to end this acceptor loop immediately from thread A (main thread), but seems like I have to wait until the time interval finishes.. Is there a way to disrupt the select function from another thread so thread B can quit instantly?

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  • How to display data into datagridview using multi thread?

    - by Mark
    Hi, I have application where I read/receive data all the time (text) and I need to display this data into datagridview, what is the best way to do that in real time, so the data will be changed all the time. I thought about multi threading, if this is a good idea can you guide me with link to explain how to implement it. Thanks

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  • Standard term for a thread I/O reorder buffer?

    - by Crashworks
    I have a case where many threads all concurrently generate data that is ultimately written to one long, serial file. I need to somehow serialize these writes so that the file gets written in the right order. ie, I have an input queue of 2048 jobs j0..jn, each of which produces a chunk of data oi. The jobs run in parallel on, say, eight threads, but the output blocks have to appear in the file in the same order as the corresponding input blocks — the output file has to be in the order o0o1o2... The solution to this is pretty self evident: I need some kind of buffer that accumulates and writes the output blocks in the correct order, similar to a CPU reorder buffer in Tomasulo's algorithm, or to the way that TCP reassembles out-of-order packets before passing them to the application layer. Before I go code it, I'd like to do a quick literature search to see if there are any papers that have solved this problem in a particularly clever or efficient way, since I have severe realtime and memory constraints. I can't seem to find any papers describing this though; a Scholar search on every permutation of [threads, concurrent, reorder buffer, reassembly, io, serialize] hasn't yielded anything useful. I feel like I must just not be searching the right terms. Is there a common academic name or keyword for this kind of pattern that I can search on?

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  • Question on a tutorial

    - by hansa
    Hello, i´m trying to get following tutorial to run and understand: http://www.ibm.com/developerworks/web/library/wa-cometjava/index.html In the example code which can be downloaded at the bottom of the page is everything in one class with two inner classes. How can i make the the thread of "MessageSender" (Listing 3) visible to "The Weatherman" (Listing 4) so i can use it in the run method without using inner classes? Thank you hansa Reformulation of Question: How to make the send-method of inner class MessageSender make accessible in ClassThatDoSomething. Example-Code: public class Example extends HttpServlet implements CometProcessor { private MessageSender messageSender = null; @Override public void init() throws ServletException { // starts thread MessageSender } public event(CometEvent) { // Object of ClassThatDoSomething gets created started } private class ClassThatDoSomething { public void start() { Runnable runnable = new Runnable() { public void run(){ messageSender.send(message); } Thread thread = new Thread(runnable); thread.start(); } } private class MessageSender implements Runnable { public void send(String message) { //... } public void run() { //...} } }

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  • How to know who kills my threads

    - by mcabral
    I got a thread that is just banishing.. i'd like to know who is killing my thread and why. It occurs to me my thread is being killed by the OS, but i'd like to confirm this and if possible to know why it's killing it. As for the thread, i can assert it has at least 40 min of execution before dying, but it suddenly dies around 5 min. public void RunWorker() { Thread worker = new Thread(delegate() { DoSomethingForALongLongTime(); }); worker.IsBackground = true; worker.SetApartmentState(System.Threading.ApartmentState.STA); worker.Start(); }

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  • GetMessage with a timeout

    - by qdii
    I have an application which second thread calls GetMessage() in a loop. At some point the first thread realizes that the user wants to quit the application and notifies the second thread that he should terminate. As the first thread is stuck on GetMessage(), the program never quits. Is there a way to wait for messages with a timeout? I’m open to other ideas too. EDIT: (additional explanations) The second thread runs that snippet of code: while ( !m_quit && GetMessage( &msg, NULL, 0, 0 ) ) { TranslateMessage( &msg ); DispatchMessage( &msg ); } The first thread sets m_quit to true.

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  • More threads and orientation changes questions.

    - by synic
    When it comes to threads and orientation changes, it seems the normal thing to do is something like this: public class Bwent extends Activity { private static Bwent instance; @Override public void onCreate(Bundle icicle) { super.onCreate(icicle); instance = this; } //... That way, if you're making a network request with a thread, and someone changes the orientation of the phone, the thread will know to use the new Activity. However, is it possible that the thread could finish during the time Android is destroying the old Activity and creating a new one? Is there a moment in the process where the thread still might be pointing to the wrong Activity, or a partially destroyed activity? It seems like there shouldn't be, but even using a Handler created in the main thread, I'm having intermittent issues with a thread trying to update an object that no longer exists. It's rare, but it does happen.

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  • How do I know that a process has more than 1 thread?

    - by Richard77
    I'have typed ps -ALF and got the following results. Actually there are more to the tow lines that I typed. UID PID PPID LWP C NLWP SZ RSS PSR STIME TTY TIME CMD root 1 0 1 0 1 5900 1644 1 Nov05 ? 00:00:05 /sbin/init root 2 0 2 0 1 0 0 0 Nov05 ? 00:00:00 [kthreadd] I'm supposed to find which process has more than 1 threads. Which column am I supposed to examine? Thanks for helping

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