Hi. now im doing parallel GA for my final project using C++. But now im having a problem with my program. when im running my program this kind of error happened :

One of the processes started by mpirun has exited with a nonzero exit
code. This typically indicates that the process finished in error.
If your process did not finish in error, be sure to include a "return
0 " or "exit(0)" in your C code before exiting the application.

PID 26349 failed on node n0 (10.1.1.1) due to signal 13 .

I hope there is someone can help me explain whats wrong with my program and whats the maeaning by signal 13. Thanks

Here is algorithm of my program (most of my parallel program at function Objective1) :

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int main (argc, argv) { //all in main is master part

MPI::Init(argc, argv);

master = id = 0;

if (id == master) {

ga(); //calling the function GA

MPI::Finalize();

} //end master

} // end main
.
.
.
void ga(); {
.
.
.
float Objective1();

} //function ga

void svm_train(); //function svm_train

float Objective1(); float Objective1(GAGenome& g)
{

int p, id, slave;
int master = 0;
int tag = 15;
MPI::Status status;

id = MPI::COMM_WORLD.Get_rank();
   p = MPI::COMM_WORLD.Get_size();

MPI::Request send[p], recv[p];

GA1DBinaryStringGenome & genome = (GA1DBinaryStringGenome &)g;
fstream file_index(indexf,ios::trunc|ios::in|ios::out);//create file for index output
double score=0.0;

if (id == master) {

    if(!file_index)
    {
        cerr << "Cannot open index1 file " << file_index << " for input.\n";
        exit(1);
    }

    cout<<"chromosome value "<<++bilang<<": ";
        for (int i=0; i<genome.length(); i++)
    {
            cout<<(genome.gene(i));
            file_index<<( genome.gene(i));
    }
            cout<<" ";
            file_index<<endl;
            file_index.close();

    for (slave = 1; slave < p; slave++) {
           //cout<<"sending to slave "<<slave<<" from "<<id<<endl;
       send[slave] = MPI::COMM_WORLD.Isend(&indexf, 1, MPI::CHAR, bilang, tag);
       send[slave] = MPI::COMM_WORLD.Isend(&file_index, 1, MPI::CHAR, bilang, tag);

    }//end for

    }//end master
    else {

    recv[slave] = MPI::COMM_WORLD.Irecv(&indexf, 1, MPI::CHAR, master, tag);
    recv[slave] = MPI::COMM_WORLD.Irecv(&file_index, 1, MPI::CHAR, master, tag);

    featureselection_train(); //select features (genes) from s2AMLALL_train.fs.data
    featureselection_test(); //select features (genes) from s2AMLALL_test.fs.data
    svm_train();

    send[slave] = MPI::COMM_WORLD.Isend(&cvscore, 1, MPI::DOUBLE, master, tag);

    }//end slaves

    if (id == master) {

    for (slave = 1; slave < bilang; slave++) {
    recv[slave] = MPI::COMM_WORLD.Irecv(&cvscore, 1, MPI::CHAR, slave, tag);

    }//end for

    //MPI::Request::Waitall(p, recv);

    //svm__test();
    //score=testscore;
    cout<<" cvs in fitness: "<<cvscore<<" "<<endl;

    score=cvscore;

    }//end master

    return score;
}