#include "stdio.h"
#include <stdlib.h>
#include <math.h>
#include <mpic++.h>
int main(int argc, char *argv[])
{
int process_Rank, size_Of_Comm;
double distro_Array[] = {1, 2, 3, 4, 5, 6 ,7, 8, 9, 10, 11, 12, 13, 14}; // data to be distributed
int N = sizeof(distro_Array)/sizeof(distro_Array[0]);
MPI_Init(&argc, &argv);
MPI_Comm_size(MPI_COMM_WORLD, &size_Of_Comm);
MPI_Comm_rank(MPI_COMM_WORLD, &process_Rank);
double scattered_Data[2];
int i;
if(process_Rank==0)
{
for(i=1;i<size_Of_Comm;i++)
{
if(2*i<=N)
{
printf("scattering data %f\n", *((distro_Array)+2*i));
MPI_Send(
distro_Array+2*(i-1), //Address of the message we are sending.
2, //Number of elements handled by that address.
MPI_DOUBLE, //MPI_TYPE of the message we are sending.
i, //Rank of receiving process
1, //Message Tag
MPI_COMM_WORLD //MPI Communicator
);
}
}
}
else
{
printf("waiting for data by %d\n", process_Rank);
if(2*process_Rank<=N)
{
MPI_Recv(
&scattered_Data, //Address of the message we are receiving.
2, //Number of elements handled by that address.
MPI_DOUBLE, //MPI_TYPE of the message we are sending.
0, //Rank of sending process
1, //Message Tag
MPI_COMM_WORLD, //MPI Communicator
MPI_STATUS_IGNORE //MPI Status Object
);
printf("Process %d has received: ",process_Rank);
double sum=0;
for(int i =0;i<2;i++)
{
printf("%f ", scattered_Data[i]);
sum += scattered_Data[i];
}
MPI_Send(
&sum, //Address of the message we are sending.
1, //Number of elements handled by that address.
MPI_DOUBLE, //MPI_TYPE of the message we are sending.
0, //Rank of receiving process
1, //Message Tag
MPI_COMM_WORLD //MPI Communicator
);
printf("\n");
}
}
MPI_Barrier(MPI_COMM_WORLD); // all the sub ranks/processes waits here
/* process 0 will aggregate the results*/
if(process_Rank==0)
{
for(i=1;i<size_Of_Comm;i++)
{
double sum=0;
MPI_Recv(
&sum, //Address of the message we are receiving.
1, //Number of elements handled by that address.
MPI_DOUBLE, //MPI_TYPE of the message we are sending.
i, //Rank of sending process
1, //Message Tag
MPI_COMM_WORLD, //MPI Communicator
MPI_STATUS_IGNORE //MPI Status Object
);
printf("Process %d has sent: %f \n", i, sum);
}
}
MPI_Finalize();
return 0;
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C++ is a widely used middle-level programming language.
When ever you want to perform a set of operations based on a condition If-Else is used.
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You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.
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For loop is used to iterate a set of statements based on a condition.
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While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.
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return_type function_name(parameters);
function_name (parameters)
return_type function_name(parameters) {
// code
}