image_parts_in_order.c
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	#include <stdio.h>
	#include <mpi.h>

	#define image_size 1024

	int main(int argc, char *argv[]) {
	int myrank, mysize;
	int * imgPart;
	int * buf;
	int i;
	int partSize;

	MPI_Request request;
	MPI_Status status;
	MPI_Init(&argc, &argv);
	MPI_Comm_rank(MPI_COMM_WORLD, &myrank);
	MPI_Comm_size(MPI_COMM_WORLD, &mysize);

	imgPart = malloc(image_size/mysize * sizeof(int));

	/* Generate image parts */
	for (i=0; i < (image_size/mysize) ; i++){
	imgPart[i] = myrank * 1;
	}
	partSize = image_size/mysize;
	/* Each process sends */
	MPI_Isend(imgPart, partSize, MPI_INT, 0, 0, MPI_COMM_WORLD, &request);

	// Process 0 receives all parts into buf
	if (myrank == 0){
	buf = malloc(image_size* sizeof(int));
	for (i=0; i<mysize; i++){
	MPI_Recv(buf + i*(image_size/mysize), (image_size/mysize), MPI_INT, i, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
	}
	}

	MPI_Wait(&request, MPI_STATUS_IGNORE);

	free(imgPart);
	if (myrank==0) free(buf);

	MPI_Finalize();
	}