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Subject: Re: [OMPI users] Calling a variable from another processor
From: Christoph Niethammer (niethammer_at_[hidden])
Date: 2014-01-09 06:29:00


I suggest you have a look onto the MPI one-sided functionality (Section 11 of the MPI Spec 3.0).
Create a window to allow the other processes to access the arrays A directly via MPI_Get/MPI_Put.
Be aware of synchronization which you have to implement via MPI_Win_fence or manual locking.


Christoph Niethammer
High Performance Computing Center Stuttgart (HLRS)
Nobelstrasse 19
70569 Stuttgart
Tel: ++49(0)711-685-87203
email: niethammer_at_[hidden]
----- Ursprüngliche Mail -----
Von: "Pradeep Jha" <pradeep_at_[hidden]>
An: "Open MPI Users" <users_at_[hidden]>
Gesendet: Donnerstag, 9. Januar 2014 12:10:51
Betreff: [OMPI users] Calling a variable from another processor
I am writing a parallel program in Fortran77. I have the following problem: 1) I have N number of processors.
2) Each processor contains an array A of size S.
3) Using some function, on every processor (say rank X), I calculate the value of two integers Y and Z, where Z<S. (the values of Y and Z are different on every processor)
4) I want to get the value of A(Z) on processor Y to processor X. 
I thought of first sending the numerical value X to processor Y from processor X and then sending A(Z) from processor Y to processor X. But it is not possible as processor Y does not know the numerical value X and so it won't know from which processor to receive the numerical value X from. 
I tried but I haven't been able to come up with any code which can implement this action. So I am not posting any codes. 
Any suggestions? 
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