// version using Java graphical display server over TCP/IP

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<math.h>
#include<mpi.h>


/* two values converge if their difference is less than EPSILON: */
//   #define EPSILON 1e-5

#define EPSILON 1e-5
#define PI 3.1415927

/* N is size of NxN matrix, M is size of MxM quadrant, P is P*P workers */
#define N 288  
#define M (2+N/2)
#define P 2
// M is the dimension of each worker quadrant, which contains ghost vectors

/**** for dynamically allocated, large contiguous arrays ****/
typedef double NROW[N+2];  
NROW *Data;   /* main data matrix - exists only on root process */
// first and last rows are for the initial, fixed values.

typedef double QROW[M];  // M is already N/2 + 2
QROW *Q;   /* one quadrant  - needed by every process */
QROW *R;   /* swap buffer */

/* macro to compute start address of quadrant in mesh */
/* These quadrants will overlap  (2x2 mesh assumed)  */
#define QUADRANT(DD,y,x) (DD[y*(N/2)]+(x*(N/2)))

int mycoord[2];  /* stores mesh coordinates */
int locate[P][P];  /* used by master to locate workers in mesh */
#define YCORD mycoord[0]
#define XCORD mycoord[1]
#define NORTH 0
#define SOUTH 1
#define EAST 2
#define WEST 3
#define SND 0
#define RCV 1


MPI_Comm WORKERS, MESH;
MPI_Datatype QUAD;   // quadrant submatrix
MPI_Datatype COLUMN;  // one column in quadrant

void master();
void worker();
void registerworkers();  /* used by master */
void registercoord(int,int);  /* used by worker */


// number of iterations before a convergence vote and display update:
int CVN = 40;


///////////////////
void visualsetup();   // for graphics
void visualize(NROW *);   // for graphics
void visualcleanup();
char* srvip;  // ip address of Java graphics server
//////////////////