1 static char help[] = "Demonstrates calling Trilinos and then PETSc in the same program.\n\n";
2
3 /*
4 Example obtained from: http://trilinos.org/docs/dev/packages/tpetra/doc/html/Tpetra_Lesson01.html
5 */
6
7 #include <petscsys.h>
8 #include <Tpetra_DefaultPlatform.hpp>
9 #include <Tpetra_Version.hpp>
10 #include <Teuchos_GlobalMPISession.hpp> // used if Trilinos is the one that starts up MPI
11
12 // Do something with the given communicator. In this case, we just
13 // print Tpetra's version to stdout on Process 0 in the given
14 // communicator.
exampleRoutine(const Teuchos::RCP<const Teuchos::Comm<int>> & comm)15 void exampleRoutine(const Teuchos::RCP<const Teuchos::Comm<int>> &comm)
16 {
17 if (comm->getRank() == 0) {
18 // On (MPI) Process 0, print out the Tpetra software version.
19 std::cout << Tpetra::version() << std::endl << std::endl;
20 }
21 }
22
main(int argc,char ** argv)23 int main(int argc, char **argv)
24 {
25 // These "using" declarations make the code more concise, in that
26 // you don't have to write the namespace along with the class or
27 // object name. This is especially helpful with commonly used
28 // things like std::endl.
29 using std::cout;
30 using std::endl;
31 // Start up MPI, if using MPI. Trilinos doesn't have to be built
32 // with MPI; it's called a "serial" build if you build without MPI.
33 // GlobalMPISession hides this implementation detail.
34 //
35 // Note the third argument. If you pass GlobalMPISession the
36 // address of an std::ostream, it will print a one-line status
37 // message with the rank on each MPI process. This may be
38 // undesirable if running with a large number of MPI ranks.
39 // You can avoid printing anything here by passing in either
40 // NULL or the address of a Teuchos::oblackholestream.
41 Teuchos::GlobalMPISession mpiSession(&argc, &argv, NULL);
42 // Get a pointer to the communicator object representing
43 // MPI_COMM_WORLD. getDefaultPlatform.getComm() doesn't create a
44 // new object every time you call it; it just returns the same
45 // communicator each time. Thus, you can call it anywhere and get
46 // the same communicator. (This is handy if you don't want to pass
47 // a communicator around everywhere, though it's always better to
48 // parameterize your algorithms on the communicator.)
49 //
50 // "Tpetra::DefaultPlatform" knows whether or not we built with MPI
51 // support. If we didn't build with MPI, we'll get a "communicator"
52 // with size 1, whose only process has rank 0.
53 Teuchos::RCP<const Teuchos::Comm<int>> comm = Tpetra::DefaultPlatform::getDefaultPlatform().getComm();
54
55 PetscFunctionBeginUser;
56 PetscCall(PetscInitialize(&argc, &argv, nullptr, help));
57
58 // Get my process' rank, and the total number of processes.
59 // Equivalent to MPI_Comm_rank resp. MPI_Comm_size.
60 const int myRank = comm->getRank();
61 const int size = comm->getSize();
62 if (myRank == 0) cout << "Total number of processes: " << size << endl;
63 // Do something with the new communicator.
64 exampleRoutine(comm);
65 // This tells the Trilinos test framework that the test passed.
66 if (myRank == 0) cout << "End Result: TEST PASSED" << endl;
67 // GlobalMPISession calls MPI_Finalize() in its destructor, if
68 // appropriate. You don't have to do anything here! Just return
69 // from main(). Isn't that helpful?
70 PetscCall(PetscFinalize());
71 return 0;
72 }
73
74 /*TEST
75
76 build:
77 requires: trilinos
78
79 test:
80 nsize: 3
81 filter: grep -v "Tpetra in Trilinos"
82
83 TEST*/
84