Das Beispiel habe ich von https:\/\/www.mpi-forum.org\/docs\/mpi-3.1\/mpi31-report\/node425.htm
\nJeder Thread erstellt einen MPI Datentyp welcher die Offsett Addressen der struct Member Variablen hat.
\nThread 1 sendet Daten zu Thread 0
\nThread 0 empfaenge Daten von Thread1 und seine eigenen Daten, so dass alle in einem Array dann liegen.<\/p>\n
\r\n\/\/ This example is based on https:\/\/www.mpi-forum.org\/docs\/mpi-3.1\/mpi31-report\/node425.htm\r\n\/\/ Jeder Thread erstellt einen MPI Datentyp welcher die Offsett Addressen der struct Member Variablen hat.\r\n\/\/ Thread 1 sendet Daten zu Thread 0\r\n\/\/ Thread 0 empfaenge Daten von Thread1 und seine eigenen Daten, so dass alle in einem Array dann liegen.\r\n\r\n#include <iostream>\r\n#include <array>\r\n\r\n#include <mpi.h>\r\n\r\nint my_rank;\r\nint nThreads;\r\n\r\nstruct basetype_t {\r\n double volstep = 0;\r\n double volTot = 0;\r\n};\r\n\r\n\/\/ Vererbung ist nicht erlaubt\r\nstruct type_t {\r\n char ID[50];\r\n int i = 0;\r\n float x = 0;\r\n \/\/ Ein Container wie std::vector zwischen den Datentypen scheint wohl zu funktionieren, ist in Fortran aber explizit nicht erlaubt.\r\n\/\/ std::vector<int> unused;\r\n bool l = false;\r\n double d = 0;\r\n basetype_t base;\r\n};\r\n\r\n\/\/ Check MPI Error code\r\nvoid check(int ierr) {\r\n if (ierr != MPI_SUCCESS) {\r\n char err_recvbuffer[MPI_MAX_ERROR_STRING];\r\n int resultlen;\r\n MPI_Error_string(ierr, err_recvbuffer, &resultlen);\r\n std::cerr << err_recvbuffer << "\\n";\r\n MPI_Finalize();\r\n }\r\n}\r\n\r\n\/\/ create new MPI datatype based on the addresses of the member variables of the type we want to send\r\nMPI_Datatype createMPItyp() {\r\n type_t foo;\r\n MPI_Aint base;\r\n check(MPI_Get_address(&foo, &base));\r\n\r\n \/\/ Fuer jede member Variable die gesendet werden soll, Typ und Addresse bestimmen\r\n const int nMembervarsToSend = 7;\r\n std::array<MPI_Datatype, nMembervarsToSend> types;\r\n std::array<int,nMembervarsToSend> blocklen;\r\n std::array<MPI_Aint, nMembervarsToSend> disp;\r\n\r\n types[0] = MPI_INT;\r\n blocklen[0] = 1;\r\n check(MPI_Get_address(&foo.i, &disp[0]));\r\n\r\n types[1] = MPI_FLOAT;\r\n blocklen[1] = 1;\r\n check(MPI_Get_address(&foo.x, &disp[1]));\r\n\r\n types[2] = MPI_LOGICAL;\r\n blocklen[2] = 1;\r\n check(MPI_Get_address(&foo.l, &disp[2]));\r\n\r\n types[3] = MPI_DOUBLE;\r\n blocklen[3] = 1;\r\n check(MPI_Get_address(&foo.d, &disp[3]));\r\n\r\n types[4] = MPI_CHAR;\r\n blocklen[4] = sizeof(foo.ID);\r\n check(MPI_Get_address(&foo.ID, &disp[4]));\r\n\r\n types[5] = MPI_DOUBLE;\r\n blocklen[5] = 1;\r\n check(MPI_Get_address(&foo.base.volstep, &disp[5]));\r\n\r\n types[6] = MPI_DOUBLE;\r\n blocklen[6] = 1;\r\n check(MPI_Get_address(&foo.base.volTot, &disp[6]));\r\n\r\n if(my_rank == 0) {\r\n std::cout << "Base Address " << std::hex << base << "\\n";\r\n std::cout << "Addresses ";\r\n for(auto& x : disp) {\r\n std::cout << " " << std::hex << x;\r\n }\r\n std::cout << std::dec << "\\n";\r\n }\r\n\r\n \/\/ Addresse zu Offset umrechnen\r\n for(auto& x : disp) {\r\n x -= base;\r\n }\r\n\r\n if(my_rank == 0) {\r\n std::cout << "Displacement";\r\n for(auto& x : disp) {\r\n std::cout << " " << x;\r\n }\r\n std::cout << "\\n";\r\n }\r\n\r\n MPI_Datatype newMPItype;\r\n check(MPI_Type_create_struct(nMembervarsToSend, blocklen.data(), disp.data(), types.data(), &newMPItype));\r\n check(MPI_Type_commit(&newMPItype));\r\n\r\n return newMPItype;\r\n}\r\n\r\nvoid doRank0(MPI_Datatype newMPItype) {\r\n type_t sendbuffer;\r\n strcpy(sendbuffer.ID, "Kreis100");\r\n sendbuffer.i = 10;\r\n sendbuffer.x = 1.2f;\r\n sendbuffer.d = 1.23;\r\n sendbuffer.l = true;\r\n sendbuffer.base.volstep = 1.34;\r\n sendbuffer.base.volTot = 1.56;\r\n\r\n int displacements[nThreads], counts[nThreads];\r\n\r\n std::vector<type_t> recvbuffer(2);\r\n std::cout << my_rank << " Receiving...\\n";\r\n\r\n int root_rank = 0;\r\n displacements[0] = 0;\r\n displacements[1] = 1;\r\n counts[0] = 1;\r\n counts[1] = 1;\r\n \/\/ MPI_Gatherv(recvbuffer_send,count_send, datatype_send, recvbuffer_recv, counts_recv, displacements, datatype_recv, root,comm)\r\n check(MPI_Gatherv(&sendbuffer, 1, newMPItype, recvbuffer.data(), counts, displacements, newMPItype, root_rank, MPI_COMM_WORLD));\r\n std::cout << my_rank << " Done receiving\\n";\r\n\r\n std::cout << my_rank << " content of struct:\\n";\r\n for(const type_t& buf : recvbuffer) {\r\n std::cout << "ID " << buf.ID << "\\n";\r\n std::cout << "i " << buf.i << "\\n";\r\n std::cout << "x " << buf.x << "\\n";\r\n std::cout << "d " << buf.d << "\\n";\r\n std::cout << "l " << buf.l << "\\n";\r\n std::cout << "volstep " << buf.base.volstep << "\\n";\r\n std::cout << "volTot " << buf.base.volTot << "\\n\\n";\r\n }\r\n}\r\n\r\nvoid doRank1(MPI_Datatype newMPItype) {\r\n type_t sendbuffer;\r\n int displacements[nThreads], counts[nThreads];\r\n\r\n strcpy(sendbuffer.ID, "Kreis200");\r\n sendbuffer.i = 20;\r\n sendbuffer.x = 2.2;\r\n sendbuffer.d = 2.23;\r\n sendbuffer.l = true;\r\n sendbuffer.base.volstep = 2.34;\r\n sendbuffer.base.volTot = 2.56;\r\n\r\n std::cout << my_rank << " Sending...\\n";\r\n \/\/ MPI_Gatherv(recvbuffer_send,count_send, datatype_send, recvbuffer_recv, counts_recv, displacements, datatype_recv, root,comm)\r\n int root_rank = 0;\r\n check(MPI_Gatherv(&sendbuffer, 1, newMPItype, NULL, counts, displacements, newMPItype, root_rank, MPI_COMM_WORLD));\r\n std::cout << my_rank << " Done sending\\n";\r\n}\r\n\r\nint main(int argc, char* argv[]) {\r\n MPI_Init(&argc, &argv);\r\n\r\n \/\/ Get number of processes and check only 2 processes are used\r\n MPI_Comm_size(MPI_COMM_WORLD, &nThreads);\r\n if(nThreads != 2) {\r\n std::cout << "Start with 2 threads.\\n";\r\n MPI_Abort(MPI_COMM_WORLD, EXIT_FAILURE);\r\n }\r\n\r\n MPI_Comm_rank(MPI_COMM_WORLD, &my_rank);\r\n MPI_Datatype newMPItype = createMPItyp();\r\n\r\n switch(my_rank) {\r\n case 0: doRank0(newMPItype); break;\r\n case 1: doRank1(newMPItype); break;\r\n };\r\n\r\n MPI_Finalize();\r\n\r\n return EXIT_SUCCESS;\r\n}\r\n\r\n<\/pre>\n$ mpic++ -g -ggdb -Wall test_MPI_struct.cpp <\/p>\n
$ mpiexec -n 2 .\/a.out
\n1 Sending...
\n1 Done sending
\nBase Address 7ffd83f7e180
\nAddresses 7ffd83f7e1b4 7ffd83f7e1b8 7ffd83f7e1bc 7ffd83f7e1c0 7ffd83f7e180 7ffd83f7e1c8 7ffd83f7e1d0
\nDisplacement 52 56 60 64 0 72 80
\n0 Receiving...
\n0 Done receiving
\n0 content of struct:
\nID Kreis100
\ni 10
\nx 1.2
\nd 1.23
\nl 1
\nvolstep 1.34
\nvolTot 1.56<\/p>\n
ID Kreis200
\ni 20
\nx 2.2
\nd 2.23
\nl 1
\nvolstep 2.34
\nvolTot 2.56\n<\/p><\/blockquote>\n","protected":false},"excerpt":{"rendered":"
Das Beispiel habe ich von https:\/\/www.mpi-forum.org\/docs\/mpi-3.1\/mpi31-report\/node425.htm Jeder Thread erstellt einen MPI Datentyp welcher die Offsett Addressen der struct Member Variablen hat. Thread 1 sendet Daten zu Thread 0 Thread 0 empfaenge Daten von Thread1 und seine eigenen Daten, so dass alle in einem Array dann liegen. \/\/ This example is based on https:\/\/www.mpi-forum.org\/docs\/mpi-3.1\/mpi31-report\/node425.htm \/\/ Jeder […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[17],"class_list":["post-5025","post","type-post","status-publish","format-standard","hentry","category-allgemein","tag-cpp"],"_links":{"self":[{"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=\/wp\/v2\/posts\/5025","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=5025"}],"version-history":[{"count":3,"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=\/wp\/v2\/posts\/5025\/revisions"}],"predecessor-version":[{"id":5028,"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=\/wp\/v2\/posts\/5025\/revisions\/5028"}],"wp:attachment":[{"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=5025"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=5025"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/roboblog.fatal-fury.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=5025"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}