MPI sorter with buffers, missing SnowPlow technique

2026-10-07 01:14:50 +00:00 · 2023-12-01 01:57:05 +00:00
parent 7a05f4d1c0
commit c2865d50cf
20 changed files with 1431 additions and 0 deletions
@@ -0,0 +1,72 @@
+#include <mpi.h>
+#include <iostream>
+
+/*
+MPI_Send(
+        void* data,              //data buffer
+        int count,               //count of elements
+        MPI_Datatype datatype,   //type of element
+        int destination,         //rank of receiver
+        int tag,                 //tag of message
+        MPI_Comm communicator    //communicator
+        )
+MPI_Recv(
+        void* data,              //data buffer
+        int count,               //count of elements
+        MPI_Datatype datatype,   //type of element
+        int source,              //rank of receiver
+        int tag,                 //tag of message
+        MPI_Comm communicator,   //communicator
+        MPI_Status* status       //about received message
+        )
+*/
+int main(int argc, char* argv[])
+{
+    const long long PINGPONG_MAX = 3;
+
+    MPI_Init(NULL, NULL);   //Initialize the MPI environment
+
+    int world_size;
+    MPI_Comm_size(MPI_COMM_WORLD, &world_size);    //Get the number of processes
+
+    int world_rank;
+    MPI_Comm_rank(MPI_COMM_WORLD, &world_rank);    //Get the number of process
+
+    if (world_size % 2 != 0)
+    {
+        std::cerr << "World size must be pair, actually is " << world_rank+1 << " (odd)" << std::endl;
+        MPI_Abort(MPI_COMM_WORLD, 1);
+    }
+
+    long long pingpong_count = 0;
+    int partner_rank;
+    if (world_rank % 2 == 0)
+        partner_rank = (world_rank + 1);
+    else
+        partner_rank = (world_rank - 1);
+    std::cout << "Process (rank " << world_rank+1 << "/" << world_size << "): my partner is " << partner_rank+1 << std::endl;
+
+    MPI_Barrier(MPI_COMM_WORLD);
+    if (world_rank == 0)
+        std::cout << "Passed Barrier" << std::endl;
+
+    while (pingpong_count < PINGPONG_MAX)
+    {
+        if (world_rank%2 == pingpong_count%2)
+        {
+            pingpong_count++;
+            // MPI_Send(data, count, datatype, dest, tag, communicator)
+            MPI_Send(&pingpong_count, 1, MPI_LONG_LONG, partner_rank, 0, MPI_COMM_WORLD);
+            std::cout << "Process (rank " << world_rank+1 << "/" << world_size << ") sent '" << pingpong_count << "' to " << partner_rank+1 << std::endl;
+        }
+        else
+        {
+            // MPI_Recv(data, count, datatype, source, tag, communicator, status)
+            MPI_Recv(&pingpong_count, 1, MPI_LONG_LONG, partner_rank, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
+            std::cout << "Process (rank " << world_rank+1 << "/" << world_size << ") received '" << pingpong_count << "' from " << partner_rank+1 << std::endl;
+        }
+    }
+
+    MPI_Finalize(); //Clean up the MPI environment
+    return 0;
+}