However, since it is multithreaded, I would like (and need!) to have one dedicated vector per thread. I haven't been able to find an example of how to do this online. Is it even possible?
I have a class which I wrote and one of its object is "SerialPort" .NET class. In my MainWindow I created instance of my class called "SerialPortComm", then I send through some functions of mine, commands to the Serial Port, and I receive answers through "DataReceived" event.
But when I trying to use Dispatcher.BeginInvoke to write my data I have received (successfully), nothing shows on the RichTextBox which I'm trying to write to.
What can caused that, and How I can make it works?
SerialPortComm.cs
public partial class SerialPortComm : UserControl { public SerialPort mySerialPort = new SerialPort(); public void Open_Port(string comNumber, int baudRate) { mySerialPort.PortName = comNumber; mySerialPort.BaudRate = baudRate;
I wrote code that finds the number of prime numbers in a range entered by the user. Now I'm attempting to make it run in parallel with the number of threads I assign it to have. I'm using blocking technique, so I'm assigning, in this scenario, 4 threads - 1/4 of the numbers in the range to the first array, and the next 1/4 of the numbers in the range to the next array and so on. Then I want to execute the prime number counting code in parallel. I'm using openMP to do this. I'm having difficulty setting it all up properly. I have a little experience with pthreads but little with openMP and am struggling in how this should be done.
I am using map for assigning an identifiers for a line from file in c++. Also i am using IDs for a pattern in line {name, operator, val} which is separated by ';'. I am using read_pub() for calculating how many patterns are there in a line.
I'm quite new to openMP, mostly used pthreads and mpi before. Now I like to tinker a bit with openMP, but haven't found any good docs, reference list or similar.
What's the equivalent to pthread's mutex lock in openMP?
Code: #pragma omp parallel for for(i=0; i<n ; i++){ // Do something intelligent... // If needed handle a shared variable. }
I'm trying to write a small brute force application in C on Ubuntu 14.04.1 using Code::Blocks with gcc-4.8.2. It's nothing special and just for practice.The focus is on a parallel procedure that generates strings by use of OpenMP. Every time a string is generated, the counter variable should be incremented. At the end, regardless of whether the search string was matched or not, it outputs the correct number of all generated strings (counts).It works fine so far.Here is my source code example:
Code:
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <omp.h> /* Global variables */ const char Literals[] = "abcdefghijklmnopqrstuvwxyz"; const int NLiterals = sizeof( Literals ) - 1; // NLiterals = 26 Bytes. const char SearchString[] = "test"; // I.e. until 'test' there are 355414 counts. char MatchString[16]; }
[code]...
This should speed up the process of generating strings. But if I do so, always when the program has a match the number of counted strings is wrong. Here are some possible "wrong" outputs: Code: Match: 'test'! 40710 tries. <-- number of tries (counts) is wrong! or Code: Match: 'test'! 40375 tries. <-- number of tries (counts) is wrong! But if the program doesn't have a match (i.e. when I change SearchString to something like the following line), then the number of counts is correct: Code: const char SearchString[] = "test0"; The only thing I have to do before, is to change the follow line from:
Code:
printf( " No match! %u tries. ", Count / 8 ); to Code: printf( " No match! %u tries. ", Count );
But also it can happen that there is no output. Like an infinite or endless loop. How can I improve the source code in order that the correct number of counts is always displayed and what can be the reason for the endless loops time after time? Both issues appears only by the use of Code: #pragma omp for schedule( dynamic ).
I'm trying to implement Parallel loop with OpenMP. I just googled and got the below sample, but it seems its not executing parallely. It takes same amount time for code which is with parallel and without parallel.
Without Parallel : It takes 39 secs. ----------------- for (int I=0;I<100000;I++){ cout<<I<<" "; }
With Parallel : It takes 39 secs. --------------
#include<omp.h> #pragma omp parallel { #pragma omp for for (int I=0;I<100000;I++) { cout<<I<<endl; } }
Why parallel is not working and it takes same time. My machine is Dual Core.
I'm trying to optimize this code using openMP. The line I added made it run about twice as fast but I'm trying to figure out how to make it even faster. Could reshaping the loops potentially increase the speed?
//4 threads int listsize=15000; #pragma omp parallel for shared(f) private(i,j,hash) for(i = 0; i < listsize; i++) { printf("Thread: %d i: %zu wl_size: %zu ",omp_get_thread_num(),i,wl_size); for (j = 0; j < num; j++) { h = f[j] (getw(list, i)); c[h] = 1; } }
I am trying to parallelize some of my code with OpenMP. When I switch to using multiple threads I start getting random numbers that are out of the expected range.
Here is a small example:
Code: #include <stdio.h> #include </usr/local/include/gsl/gsl_rng.h> #include </usr/local/include/gsl/gsl_randist.h> int main() { int mySeed=0; const gsl_rng_type *T; T = gsl_rng_ranlxs2; gsl_rng *r_1 ;
[Code] .....
gsl_rng_uniform should only output number in the range [0,1) but with multiple threads it outputs larger number as well.
I have the following code below. I am getting a memory access violation when accessing cmd->query_string in the loop function. The loop() function is running in another thread. The cmd object appears to be destroyed after calling the send_command function. How do I create an object on the heap and access the query_string.
I was working on a problem that was best solved with chaining threads together using a blocking thread-safe queue. Eg threads A and B pass data to each other using a queue ... a simple producer consumer design A -> B. This has two benefits: 1) being that there is a buffer between the two threads to cache for a slow consumer and 2) allows for better throughput when loads of data are high because the two can run in parallel. Most of the time the design works well under load. but I found when pushing data through the threads intermittently, i.e. once about 0.5 seconds it ran poorly, mostly from what seemed to be latency introduced during the OS waking up of the consumer thread B.
What i have come up with to solve this issue is what i call an .... Its a wrapper around a basic thread safe queue and adds one extra function called .... The idea here is that if you have a simple case (or perhaps a slightly more complicated case) of two threads in a prod cons design and you know the producer will create or received the data, process it, and then push onto the queue, why not give the consumer thread a heads up to let it know the data is about to arrive. In this case call .... In this way you can have the consumer thread in a polling state anticipating the arrival of data and avoid the time to schedule it back to a running state.
Anyway, i have some code below and I was looking to get some feedback. I have tested it somewhat and it does improve the responsiveness quite substantially.
progd->count was devised to stop the thread when the recursion ended by posting a message to the main window. When it reaches 1, the def procedure sends the WMU_DISC_DONE message to set the event
All that *appears* to work; however, if I cancel the recursion thread, the list view continues to populate for a bit and then deletels all but 1 item though I send the message LVM_DELETEALLITEMS.
If I move the (tmp->canceled == TRUE) test inside of the do-while, the app gets loopy.
I have a small problem with my program. It is kinda a mess but I will try to explain you what I am trying to do. I have some threads. One of it, it attempts to detect a game client. So my code is sort of like that:
DWORD ProcessID; // The process ID of the game client void test() { char* text;
[Code]....
So basically, its like the variable changes, but only inside the thread... why does that happen?
I have an issue where I iterate through devices and make driver API calls. Unfortunately, these calls take too much time and they are interrupting my real-time scheduler. I have 12 cores, of which one is 100% and the others are < 1%.
I'd like to multi-thread this thing. So far, I've replaced:
for (DeviceIterator d = devices.begin(); d != devices.end(); ++d) { d->Write(words, numwords); }
My problem is that this didn't improve performance at all. The main thread still takes too long to execute. Is there something I need to do to prevent the main thread from blocking?
