1*c4762a1bSJed Brown 2*c4762a1bSJed Brown static char help[] = "Demonstrates calling Trilinos and then PETSc in the same program.\n\n"; 3*c4762a1bSJed Brown 4*c4762a1bSJed Brown /*T 5*c4762a1bSJed Brown Concepts: introduction to PETSc^Trilinos 6*c4762a1bSJed Brown Processors: n 7*c4762a1bSJed Brown 8*c4762a1bSJed Brown Example obtained from: http://trilinos.org/docs/dev/packages/tpetra/doc/html/Tpetra_Lesson01.html 9*c4762a1bSJed Brown T*/ 10*c4762a1bSJed Brown 11*c4762a1bSJed Brown 12*c4762a1bSJed Brown 13*c4762a1bSJed Brown #include <petscsys.h> 14*c4762a1bSJed Brown #include <Tpetra_DefaultPlatform.hpp> 15*c4762a1bSJed Brown #include <Tpetra_Version.hpp> 16*c4762a1bSJed Brown #include <Teuchos_GlobalMPISession.hpp> // used if Trilinos is the one that starts up MPI 17*c4762a1bSJed Brown 18*c4762a1bSJed Brown // Do something with the given communicator. In this case, we just 19*c4762a1bSJed Brown // print Tpetra's version to stdout on Process 0 in the given 20*c4762a1bSJed Brown // communicator. 21*c4762a1bSJed Brown void 22*c4762a1bSJed Brown exampleRoutine (const Teuchos::RCP<const Teuchos::Comm<int> >& comm) 23*c4762a1bSJed Brown { 24*c4762a1bSJed Brown if (comm->getRank () == 0) { 25*c4762a1bSJed Brown // On (MPI) Process 0, print out the Tpetra software version. 26*c4762a1bSJed Brown std::cout << Tpetra::version () << std::endl << std::endl; 27*c4762a1bSJed Brown } 28*c4762a1bSJed Brown } 29*c4762a1bSJed Brown 30*c4762a1bSJed Brown int main(int argc,char **argv) 31*c4762a1bSJed Brown { 32*c4762a1bSJed Brown PetscErrorCode ierr; 33*c4762a1bSJed Brown // These "using" declarations make the code more concise, in that 34*c4762a1bSJed Brown // you don't have to write the namespace along with the class or 35*c4762a1bSJed Brown // object name. This is especially helpful with commonly used 36*c4762a1bSJed Brown // things like std::endl. 37*c4762a1bSJed Brown using std::cout; 38*c4762a1bSJed Brown using std::endl; 39*c4762a1bSJed Brown // Start up MPI, if using MPI. Trilinos doesn't have to be built 40*c4762a1bSJed Brown // with MPI; it's called a "serial" build if you build without MPI. 41*c4762a1bSJed Brown // GlobalMPISession hides this implementation detail. 42*c4762a1bSJed Brown // 43*c4762a1bSJed Brown // Note the third argument. If you pass GlobalMPISession the 44*c4762a1bSJed Brown // address of an std::ostream, it will print a one-line status 45*c4762a1bSJed Brown // message with the rank on each MPI process. This may be 46*c4762a1bSJed Brown // undesirable if running with a large number of MPI processes. 47*c4762a1bSJed Brown // You can avoid printing anything here by passing in either 48*c4762a1bSJed Brown // NULL or the address of a Teuchos::oblackholestream. 49*c4762a1bSJed Brown Teuchos::GlobalMPISession mpiSession (&argc, &argv, NULL); 50*c4762a1bSJed Brown // Get a pointer to the communicator object representing 51*c4762a1bSJed Brown // MPI_COMM_WORLD. getDefaultPlatform.getComm() doesn't create a 52*c4762a1bSJed Brown // new object every time you call it; it just returns the same 53*c4762a1bSJed Brown // communicator each time. Thus, you can call it anywhere and get 54*c4762a1bSJed Brown // the same communicator. (This is handy if you don't want to pass 55*c4762a1bSJed Brown // a communicator around everywhere, though it's always better to 56*c4762a1bSJed Brown // parameterize your algorithms on the communicator.) 57*c4762a1bSJed Brown // 58*c4762a1bSJed Brown // "Tpetra::DefaultPlatform" knows whether or not we built with MPI 59*c4762a1bSJed Brown // support. If we didn't build with MPI, we'll get a "communicator" 60*c4762a1bSJed Brown // with size 1, whose only process has rank 0. 61*c4762a1bSJed Brown Teuchos::RCP<const Teuchos::Comm<int> > comm = Tpetra::DefaultPlatform::getDefaultPlatform ().getComm (); 62*c4762a1bSJed Brown 63*c4762a1bSJed Brown ierr = PetscInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr; 64*c4762a1bSJed Brown 65*c4762a1bSJed Brown // Get my process' rank, and the total number of processes. 66*c4762a1bSJed Brown // Equivalent to MPI_Comm_rank resp. MPI_Comm_size. 67*c4762a1bSJed Brown const int myRank = comm->getRank (); 68*c4762a1bSJed Brown const int size = comm->getSize (); 69*c4762a1bSJed Brown if (myRank == 0) { 70*c4762a1bSJed Brown cout << "Total number of processes: " << size << endl; 71*c4762a1bSJed Brown } 72*c4762a1bSJed Brown // Do something with the new communicator. 73*c4762a1bSJed Brown exampleRoutine (comm); 74*c4762a1bSJed Brown // This tells the Trilinos test framework that the test passed. 75*c4762a1bSJed Brown if (myRank == 0) { 76*c4762a1bSJed Brown cout << "End Result: TEST PASSED" << endl; 77*c4762a1bSJed Brown } 78*c4762a1bSJed Brown // GlobalMPISession calls MPI_Finalize() in its destructor, if 79*c4762a1bSJed Brown // appropriate. You don't have to do anything here! Just return 80*c4762a1bSJed Brown // from main(). Isn't that helpful? 81*c4762a1bSJed Brown ierr = PetscFinalize(); 82*c4762a1bSJed Brown return ierr; 83*c4762a1bSJed Brown } 84*c4762a1bSJed Brown 85*c4762a1bSJed Brown 86*c4762a1bSJed Brown 87*c4762a1bSJed Brown 88*c4762a1bSJed Brown /*TEST 89*c4762a1bSJed Brown 90*c4762a1bSJed Brown build: 91*c4762a1bSJed Brown requires: trilinos 92*c4762a1bSJed Brown 93*c4762a1bSJed Brown test: 94*c4762a1bSJed Brown nsize: 3 95*c4762a1bSJed Brown filter: grep -v "Tpetra in Trilinos" 96*c4762a1bSJed Brown 97*c4762a1bSJed Brown TEST*/ 98