Send chunks of 3D array using MPI subarray - c

Question

I'm a newby in MPI and I'm trying to learn how to use MPI_Type_create_subarray in order to apply it in my projects.
I've spent lots of time searching for a tutorial which could fits my needing, but without success.
So I've tried to generalize the concept in How to use MPI_Type_create_subarray
to 3D arrays, but something is still missing.
In particular my code return a Segmentation Fault error or shows wrong data when I try to see results.
I can't understand where I made a mistake
This is my code:
#include <stdio.h>
#include <stdlib.h>
#include <mpi.h>
void printarr(int ***data, int nx, int ny, int nz, char *str);
int ***allocarray(int nx, int ny, int nz);
int main(int argc, char **argv) {
/* array sizes */
const int bigsize =10;
const int subsize_x =2; const int subsize_y =2; const int subsize_z =2;
/* communications parameters */
const int sender =0;
const int receiver=1;
const int ourtag =2;
int rank, size;
MPI_Init(&argc, &argv);
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
MPI_Comm_size(MPI_COMM_WORLD, &size);
if (size < receiver+1) {
if (rank == 0)
fprintf(stderr,"%s: Needs at least %d processors.\n", argv[0], receiver+1);
MPI_Finalize();
return 1;
}
MPI_Datatype mysubarray;
int starts[3] = {0,0,0};
int subsizes[3] = {subsize_x,subsize_y,subsize_z};
int bigsizes[3] = {bigsize, bigsize, 3};
MPI_Type_create_subarray(3, bigsizes, subsizes, starts, MPI_ORDER_C, MPI_INT, &mysubarray);
MPI_Type_commit(&mysubarray);
if (rank == sender) {
int ***bigarray = allocarray(bigsize,bigsize,3);
for (int k=0; k<3; k++)
for (int j=0; j<bigsize; j++)
for(int i=0; i< bigsize; i++) {
bigarray[k][j][i] = k*(bigsize*bigsize)+j*bigsize+i;
}
printarr(bigarray, bigsize, bigsize, 3, " Sender: Big array ");
MPI_Send(&(bigarray[0][0][0]), 1, mysubarray, receiver, ourtag, MPI_COMM_WORLD);
MPI_Type_free(&mysubarray);
free(bigarray);
} else if (rank == receiver) {
int ***subarray = allocarray(subsize_x,subsize_y,subsize_z);
MPI_Recv(&(subarray[0][0][0]), subsizes[0]*subsizes[1]*subsizes[2], MPI_INT, sender, ourtag, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
printarr(subarray, subsize_x, subsize_y, subsize_z, " Receiver: Subarray -- after receive");
free(subarray);
}
MPI_Finalize();
return 0;
}
void printarr(int ***data, int nx, int ny, int nz, char *str) {
printf("-- %s --\n", str);
for(int k=0; k<nz; k++) {
printf("\n\n-----%d------\n",k);
for (int j=0; j<ny;j++) {
for (int i=0; i<nx; i++) {
printf("%3d ", data[k][j][i]);
}
printf("\n");
}
}
}
int ***allocarray(int nx, int ny, int nz) {
int*** arr = (int***)malloc(sizeof(int**)*nz);
for(int k = 0; k < nz; k++) {
arr[k]= (int**)malloc(sizeof(int*)*ny);
for(int j = 0; j< ny; j++){
arr[k][j] = (int*)malloc(sizeof(int)*nx);
for(int i = 0; i < nx; i++){
arr[k][j][i] = 0;
}
}
}
return arr;
}