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

/**
 * @author cristian.chilipirea
 *
 */

int main(int argc, char * argv[]) {
	int rank;
	int nProcesses;
	MPI_Init(&argc, &argv);

	MPI_Comm_rank(MPI_COMM_WORLD, &rank);
	MPI_Comm_size(MPI_COMM_WORLD, &nProcesses);
	printf("Hello from %i/%i\n", rank, nProcesses);

	int dest, src;

	MPI_Status Stat;
	//if(rank==0) { // This code is run by a single process
		int polynomialSize;
		int n;
		int i;
		int j;
		float x;


		FILE * polFunctionFile = fopen("a1.txt","rt");
		fscanf(polFunctionFile, "%i", &polynomialSize);
		float * a = malloc(sizeof(float)*polynomialSize);
		for(i=0;i<polynomialSize;i++) {
			fscanf(polFunctionFile, "%f", a+i);
		}
		fclose(polFunctionFile);


		for(x=0; x<3; x+=1) {
			float sum = 0;
			float xPowI = 1;
			float out_pow, in_pow;
			float out_sum = 0;
			float in_sum;
			/*for(i=0;i<polynomialSize;i++) {
				sum += xPowI * a[i];
				xPowI *= x; // more efficient than pow(x,i);
			}
			printf("%f ", sum);*/
			//printf("%f\n", x);
			//for(i=0;i<polynomialSize;i++) {
				if(rank==0){
					dest = rank+1;
					out_sum += xPowI * a[rank];
					out_pow = xPowI;
					out_pow *= x;
					MPI_Send(&out_pow, 1, MPI_FLOAT, dest, 1, MPI_COMM_WORLD);
					MPI_Send(&out_sum, 1, MPI_FLOAT, dest, 1, MPI_COMM_WORLD);



				}
				else if(rank == nProcesses-1){
					src = rank-1;
					//dest = rank+1;
					MPI_Recv(&in_pow, 1, MPI_FLOAT, src, 1, MPI_COMM_WORLD,&Stat);
					MPI_Recv(&in_sum, 1, MPI_FLOAT, src, 1, MPI_COMM_WORLD,&Stat);

					//printf("%f\n", in_pow);
					out_sum = in_sum + in_pow * a[rank];
					//out_pow = in_pow * x;
					printf("%f \n", out_sum);

				}
				else{
					src = rank - 1;
					dest = rank+1;
					MPI_Recv(&in_pow, 1, MPI_FLOAT, src, 1, MPI_COMM_WORLD,&Stat);

					sum += in_pow * a[rank];
					out_pow = in_pow* x;
					MPI_Send(&out_pow, 1, MPI_FLOAT, dest, 1, MPI_COMM_WORLD);

				}
			//}
		}

	//}

	/*for(x = 0;x<3;x++){
		float sum = 0;
		float xPowI = 1;


	}*/

	MPI_Finalize();
	return 0;
}