Hi David / users, Thanks for your mail and suggestion. Well, Can you please elaborate some more on this.
When I start program, without doing anything, nodes other than master keep waiting for the corresponding MPI_Bcast call and keep taking nearly 50% CPU while idle. When I MPI_Bcast the variable from master, then only other nodes come to normal state. This is really a problem but it is unavoidable. Also, is it possible for master to trigger a function/MPI call on all nodes using any of MPI functionalities? This will be very useful. Thank you very much for your feedback. -- regards, eye51 On Tue, Mar 1, 2011 at 8:05 AM, David Zhang <solarbik...@gmail.com> wrote: > Certainly you may call MPI functions many times, the problem is that you > need to have matching receives (or collectives) at your slave nodes, which > is only determined at run-time. Perhaps this could be done with two > communications, the first broadcast the type of communications to the slaves > (for example, 1 for collective broadcast, 2 for scatter, etc.), you encode > whatever you wish in an integer. Once the slaves receive the code they'll > respond correspondingly, posting the corresponding MPI receive. Clearly, a > way to allow the slaves to exit the while loop is needed if you want the > slaves to exit cleanly, the exit code can also be encoded in the integer you > sent out. > > On Tue, Mar 1, 2011 at 12:39 AM, Eye RCS 51 <eye.rcs...@gmail.com> wrote: > >> Hi, >> >> In an effort to make a Qt gui using MPI, I have the following: >> >> 1. Gui started in master node. >> >> 2. In Gui, through a pushbutton, a global variable x is assigned some >> value; let say, x=1000; >> >> 3. I want this value to be know to all nodes. So I used broadcast in the >> function assigning it on the master node and all other nodes. >> >> 4. I printed values of x, which prints all 1000 in all nodes. >> >> 5. Now control has reached to MPI_Finalize in all nodes except master. >> >> Now If I want to reassign value of x using pushbutton in master node and >> again broadcast to and print in all nodes, can it be done?? >> I mean, can I have an MPI function which through GUI is called many times >> and assigns and prints WHILE program is running. >> >> OR simply can I have a print function which is printing noderank value in >> all nodes whenever pushbutton is pressed while program is running. >> >> command i used is "mpirun -np 3 ./a.out". >> >> Any help will be appreciated. >> Thanks you very much. >> >> -- >> eye51 >> >> _______________________________________________ >> users mailing list >> us...@open-mpi.org >> http://www.open-mpi.org/mailman/listinfo.cgi/users >> > > > > -- > David Zhang > University of California, San Diego > > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users >
