concurrent-programming

问题 How React PHP handles async non-blocking I/O ? Nodejs uses its event queue which handles I/O on different threads. It uses libuv for this. As in PHP there isn't something like that, How React handles non-blocking I/O process on a single thread ? 回答1: React PHP provides the primary event loop of the application; you are still required to write your code in a non-blocking way since it is all on one thread. The possible solutions to this all revolve around using php differently than I am sure

问题 This question already has answers here : question about “Java Concurrency in Practice” example (6 answers) Closed 6 years ago . I am reading the book: "Java Concurrency in Practice" to better understand how java concurrency works. On chapter 3 section 3.1:Visibility There is and example in which the book tries to show how visibility problems occur. Here is the example code (Listing 3.1 in the book): public class NoVisibility { private static boolean ready; private static int number; private

问题 I have a situation where I am making several (say four) ajax calls (using AngularJS http get, if that matters) and I want each call to callback and increment a counter, so I can know when all (four) of the threads have completed. My concern is that since JavaScript does not have anything comparable to Java's "synchronized" or "volatile" keywords, that it would be possible for multiple concurrent threads to collide while incrementing a counter, thereby missing some increments. In other words,

问题 I am running a function for several sets of iterables, returning a list of all results as soon as all processes are finished. def fct(variable1, variable2): # do an operation that does not necessarily take the same amount of # time for different input variables and yields result1 and result2 return result1, result2 variables1 = [1,2,3,4] variables2 = [7,8,9,0] with ThreadPoolExecutor(max_workers = 8) as executor: future = executor.map(fct,variables1,variables2) print '[%s]' % ', '.join(map

问题 I am running a function for several sets of iterables, returning a list of all results as soon as all processes are finished. def fct(variable1, variable2): # do an operation that does not necessarily take the same amount of # time for different input variables and yields result1 and result2 return result1, result2 variables1 = [1,2,3,4] variables2 = [7,8,9,0] with ThreadPoolExecutor(max_workers = 8) as executor: future = executor.map(fct,variables1,variables2) print '[%s]' % ', '.join(map

问题 I want to implement an Anytime k-NN classifier but I cannot find a way to call the "classify(...)" method for a specific amount of time, suspend it, get the available results before the method was suspended, resume the method for a specific amount of time, suspend it, get the available results before the method was suspended, and so on... I use a data structure for getting approximate results. While the algorithm traverses the data structure, it will encounter the actual training data vector,

问题 I am trying to run 3 python programs simultaneously by running a single python program I am using the following script in a separate python program sample.py Sample.py: import subprocess subprocess.Popen(['AppFlatRent.py']) subprocess.Popen(['AppForSale.py']) subprocess.Popen(['LandForSale.py']) All the three programs including python.py is in the same folder. Error: OSError: [Errno 2] No such file or directory Can someone guide me how can i do it using subprocess.Popen method? 回答1: The file

问题 I need to make a ConcurrentBag as notifable. I need to know that is it safe? Code for the class is public class NotifiableConcurrentBag<T> : ConcurrentBag<T>, INotifyCollectionChanged where T : class { public NotifiableConcurrentBag() { dispatcher = Dispatcher.CurrentDispatcher; } private Dispatcher dispatcher; public event NotifyCollectionChangedEventHandler CollectionChanged; public new void Add(T item) { base.Add(item); if (CollectionChanged != null) { if (Thread.CurrentThread ==

问题 How do I steal 2 MSBs from an address to do an atomic operation? I'm trying to do a single word CAS An example public class Node { long key; long value; Node lchild; // format is flag1,flag2,address Node rchild; // format is flag1,flag2,address } public void createNode() { Node n1 = new Node(); //this should create a node with format 0,0,address1 } public void setFlag1(Node n1) { Now the new address should be in format 1,0,address1 } public void setFlag2(Node n1) { Now the new address should

问题 I can see how a "standard" Semaphore Class can be implemented in Java. However, I cant see how to implement a Binary Semaphore Class in Java. How does such implementation work? When should I call the wake and notify methods to wake and stop the threads that are on the semaphores? I understand what binary semaphores are, but I have no idea of how to code them. Edit Note: Realize that I said "BINARY" Semaphore class. The standard Semaphore class I already did and I know its correct so the