[Trilinos-Users] Implicit Barriers in Trilinos / Epetra

[Corey A. Henderson]

Hello,

I am experimenting with Trilinos and doing the Epetra hands-on. I have
tried Google to learn if there is a reference indicating which methods have
implicit MPI Barriers.

It seems obvious to me that there must be some, especially since no barrier
is suggested in lesson 2 here:

    // Use local indices to access the entries of x_data.
    const int localLength = x.MyLength ();
    for (int localIndex = 0; localIndex < localLength; ++localIndex) {
      // Add the value of the local index to every entry of x.
      x[localIndex] += static_cast<double> (localIndex);
    }

    // Print the norm of x.
    theNorm = 0.0;
    (void) x.Norm2 (&theNorm);
    out << "Norm of x (modified random numbers): " << theNorm << endl;

It seems to me without a barrier before the Norm2 call (or in Norm2()
itself) we'd get unexpected results.

Are these barriers documented somewhere that I can use as a reference?

Thanks,

Corey A. Henderson
PhD Candidate / NSF Graduate Fellow
Dept. of Engineering Physics
Univ. of Wisconsin - Madison
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://software.sandia.gov/pipermail/trilinos-users/attachments/20141014/5a713d50/attachment.html>