source: CIVL/examples/compare/adder/adder_par.cvl@ e2877ba

/*****************************************
 * SOURCE: adder_par.c by vsl@udel
 *         The source program is included in FEVS
 *         vsl.cis.udel.edu/fevs
 * FILE: adder_par.cvl
 * DESCRIPTION: This a manually translated 
 *   CIVL program which is based on "adder_par.c"
 *   This program sums all elements of an array
 *   up.
 *
 * AUTHOR: Ziqing Luo
 * COMMANS: civl verify adder_par.cvl 
 *          -inputNPROCSB=5 -inputNB=10
 *          or
 *          make civl
 *****************************************/

#include<civlc.cvh>
#include<stdio.h>
#include<mpi.h>
#include<civl-mpi.cvh>
#include<assert.h>

$input int NPROCS;
$input int NPROCSB;
$input int N; 
$input int NB;
$input double a[N];
$output double SUM;
$assume(0 < N && N < NB);
$assume(0 < NPROCS && NPROCS <= NPROCSB);
$assume(NPROCS <= N);

$mpi_gcomm __MPI_COMM_WORLD;

void _mpi_process(int place){
  double sum;
  double localSum = 0.0;
  int PID;
  int nprocs; 
  MPI_Comm MPI_COMM_WORLD;
  $mpi_sys_status _mpi_status = __UNINIT;

  $assert(_mpi_status == __UNINIT);
  double computeGlobalSum() {
    double result = localSum;
    double buffer;
    int i;
    MPI_Status status;

    for (i=1; i<nprocs; i++) {
      MPI_Recv(&buffer, 1, MPI_DOUBLE, i, 0, MPI_COMM_WORLD, &status);
      result += buffer;
    }
    return result;
  }
    
  int _main() {
    
    int first;
    int afterLast; 
    int i;

    MPI_COMM_WORLD = $mpi_comm_create($here, __MPI_COMM_WORLD, place);
    $mpi_init();
    MPI_Comm_size(MPI_COMM_WORLD, &nprocs);
    MPI_Comm_rank(MPI_COMM_WORLD, &PID);
    first = N * PID / nprocs;
    afterLast = N * (PID + 1) / nprocs;

    for (i=first; i<afterLast; i++) localSum += a[i];
    if (PID == 0) {
      sum = computeGlobalSum(); 
      SUM = sum;
      printf("%lf\n", sum);
    } else {
      MPI_Send(&localSum, 1, MPI_DOUBLE, 0, 0, MPI_COMM_WORLD);
    }
    $mpi_finalize();
    $mpi_comm_destroy(MPI_COMM_WORLD);
    return 0;
  }

  _main();
}

void main(){
  for(int i = 0; i<NPROCS; i++);
  for(int i = 0; i<N; i++);

  $proc procs[NPROCS];

  __MPI_COMM_WORLD = $mpi_gcomm_create($root, NPROCS);
  for(int i = 0; i<NPROCS; i++)
    procs[i] = $spawn _mpi_process(i);
  for(int i = 0; i<NPROCS; i++)
    $wait(procs[i]);
  $mpi_gcomm_destroy(__MPI_COMM_WORLD);
}