[lab3_1.c XLSS] don't debug yet

#include "mpi.h"
#include <stdio.h>
#include <stdlib.h>
#define ARRAYSIZE 1000
#define MASTER 0

int data1[ARRAYSIZE];
int data2[ARRAYSIZE];

int update(int*,int*,int);
int main(int argc, char const *argv[]) {
    int numtasks, taskid, chunksize, rc,i;
    MPI_Status status;

    MPI_Init(&argc,&argv);
    MPI_Comm_size(MPI_COMM_WORLD,&numtasks);
    MPI_Comm_rank(MPI_COMM_WORLD,&taskid);
    chunksize = ARRAYSIZE/numtasks;

    if(taskid==MASTER) {
        // Init vetor
        for (i = 0; i < ARRAYSIZE; ++i) {
            data1[i]=i;
            data2[i]=i;
        }
        /* Send each task its portion of the array - master keeps 1st part */
        offset = chunksize;
        for (i = 0; i < numtasks; ++i) {
            MPI_Send(&offset,1,MPI_INT,dest,NULL,MPI_COMM_WORLD);
            MPI_Send(&data1[offset],1,MPI_INT,dest,NULL,MPI_COMM_WORLD);
            MPI_Send(&data2[offset],1,MPI_INT,dest,NULL,MPI_COMM_WORLD);
            offset+=offset+chunksize;
        }
        /* Master does its part of the work */
        offset = 0;
        mysum = update(offset, chunksize, taskid);

        /* Wait to receive results from each task */
        for (i = 0; i < numtasks; ++i) {
            source = i;
            MPI_Recv(&offset, 1, MPI_INT, source, tag1, MPI_COMM_WORLD, &status);
            MPI_Recv(&data[offset], chunksize, MPI_FLOAT, source, tag2,
                MPI_COMM_WORLD, &status);
        }
         /* Get final sum and print sample results */
        MPI_Reduce(&mysum, &sum, 1, MPI_FLOAT, MPI_SUM, MASTER, MPI_COMM_WORLD);
        printf("*** Final sum= %d ***\n",sum);
    }   /* end of master section */
    if (taskid > MASTER) {
          /* Receive my portion of array from the master task */
          source = MASTER;
          MPI_Recv(&offset, 1, MPI_INT, source, tag1, MPI_COMM_WORLD, &status);
          MPI_Recv(&data[offset], chunksize, MPI_FLOAT, source, tag2,
            MPI_COMM_WORLD, &status);

          mysum = update(offset, chunksize, taskid);

          /* Send my results back to the master task */
          dest = MASTER;
          MPI_Send(&offset, 1, MPI_INT, dest, tag1, MPI_COMM_WORLD);
          MPI_Send(&data[offset], chunksize, MPI_FLOAT, MASTER, tag2, MPI_COMM_WORLD);

          MPI_Reduce(&mysum, &sum, 1, MPI_FLOAT, MPI_SUM, MASTER, MPI_COMM_WORLD);
    } /* end of non-master */

    return 0;
}
int update(int offset,int chunk, int taskid)
{
    int i;
    int mysum = 0;
    for (i = offset; i < offset+ chunk; ++i)
    {
        mysum+=data1[i]*data2[i]
    }
    printf("Task %d mysum = %d\n",myid,mysum);
    return mysum;
}