/*
*   Test Problem 
*
*   Program Name  EUIprob1.c
*
*   This program evaluates the trapezoidal rule estimate
*   for an integral of F(x). In this case, F(x) is exp(x)
*   evaluated for the interval of 0 to 1. Each case provides
*   2X increase in precision. Therefore each result should be
*   similar but, not the same.
*
*   Testing for Nps 1 ... 11 should execute programs.
*   Testing for Nps 12 and above should stop the program.
*
*   This program requires the following call(s)
*             MPI_Init
*             MPI_Comm_rank
*             MPI_Comm_size
*             MPI_Abort
*             MPI_Finalize
*/

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

#define KASES 11
#define F(x) (exp(x))
main (int argc, char **argv) 
{
double	TN[KASES], SUM, X, H,
	A = 0.0,
	B = 1.0;
int	nworkers, whoami, i, errcode,
	N[KASES] = {100, 200, 400, 800, 1600, 3200,
             6400, 12800, 25600, 51200, 102400}; 

/*
*    Initialize environment
*/
MPI_Init(&argc, &argv);
MPI_Comm_rank(MPI_COMM_WORLD, &whoami);
MPI_Comm_size(MPI_COMM_WORLD, &nworkers);
printf("Envirionment allocated %d workers out of %d\n",nworkers,KASES);

if (whoami > KASES) 
      MPI_Abort(MPI_COMM_WORLD, errcode);

whoami = whoami + 1;
H = (B-A)/(N[whoami]);
SUM = 0.0;
for (i = 1; i <= N[whoami]-1; i++)
     SUM = SUM+F(A+H*i);
TN[whoami] = H*((F(A)+F(B))/2.+SUM);

printf("PROBLEM 1 WITH A,B,whoami,N = %10.3f,%10.3f,%d,%d\n",A,B,
          whoami,N[whoami]);
printf("GIVES TN = %10.6f\n",TN[whoami]);
MPI_Finalize();
}