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lab1/pi_mpi.c
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#include <stdio.h> #include <string.h> |
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#include <mpi.h> |
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#define N 100000000 int main (int argc, char** argv) { int rank; int size; long long int n; long long int i; double l_sum,total_sum, x, h; MPI_Init(NULL, NULL); MPI_Comm_size(MPI_COMM_WORLD, &size); MPI_Comm_rank(MPI_COMM_WORLD, &rank); n=N; if(rank==0) { if(argc==2) { |
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n = atol(argv[1]); |
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} printf("MPI version with process = %d ", size); printf("Number of intervals: %lld ", n); } |
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MPI_Bcast(&n, 1, MPI_LONG, 0, MPI_COMM_WORLD); |
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h = 1.0/n; l_sum = 0.0; for (i = rank; i < n; i += size) { x = (i + 0.5)*h; l_sum += 4.0/(1.0 + x*x); } l_sum *= h; MPI_Reduce(&l_sum,&total_sum,1,MPI_DOUBLE,MPI_SUM,0,MPI_COMM_WORLD); if(rank==0) { printf("Pi=%0.12g ", total_sum); } MPI_Finalize(); return 0; } |