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mpi_fib_rec1.c
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mpi_fib_rec1.c
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#include <stdio.h>
#include <stdlib.h>
#include <math.h>
/* We'll be using MPI routines, definitions, etc. */
#include <mpi.h>
#define BOUND 20
/* Fibonacci Function */
int fib(int n);
int main(int argc, char *argv[])
{
int my_rank, comm_sz, local_n;
int local_start, local_end;
double total_sum = 0, local_sum = 0;
MPI_Init(&argc, &argv);
MPI_Comm_size(MPI_COMM_WORLD, &comm_sz);
MPI_Comm_rank(MPI_COMM_WORLD, &my_rank);
printf("start process %d of %d processes\n", my_rank, comm_sz);
local_n = BOUND / comm_sz; /* same for all processes */
int fib_index;
for (int i = 0; i < local_n; i++)
{
fib_index = comm_sz*i + my_rank + 1;
local_sum += pow(fib(fib_index), -1);
}
MPI_Reduce(&local_sum, &total_sum, 1, MPI_DOUBLE, MPI_SUM, 0, MPI_COMM_WORLD);
// (const void *sendbuf, void *recvbuf, int count,
// MPI_Datatype datatype, MPI_Op op, int root,
// MPI_Comm comm)
/* Print the result */
if (my_rank == 0)
{
printf("Sum of Fibonacci Reciprocals: %f\n", total_sum);
}
/* Shut down MPI */
MPI_Finalize();
return 0;
} /* main */
/*------------------------------------------------------------------
* Function: Fibonacci
* Purpose: Returns n th fibonacci number
* Input args: x
*/
int fib(int n)
{
if (n == 1)
return 1;
if (n == 2)
return 2;
return fib(n-1) + fib(n-2);
} /* fib */