Key Data Structures

int p; /* Total number of processes */

MPI_Comm comm; /* Communicator for entire grid */

MPI_Comm row_comm; /* Communicator for my row */

MPI_Comm col_comm; /* Communicator for my col */

int q; /* Order of grid */

int my_row; /* My row number */

int my_col; /* My column number */

int my_rank; /* My rank in the grid comm */

} GRID_INFO_T;

#define MAX 65536

typedef struct {

int n_bar;

float entries[MAX];

} LOCAL_MATRIX_T;

#define Order(A) ((A)->n_bar)

#define Entry(A,i,j) (*(((A)->entries) + ((A)->n_bar)*(i) + (j)))