Instruction illégale 4 sur Mac utilisant C++

Question

Je cours ce code sur mon mac (10.8.2) par le terminal et pour certain n il se termine par "Instruction illégale 4" quelqu'un sait pourquoi, ou comment l'arrêter?

Je suis confus que le code fonctionne bien sauf pour n = 43, 45, 47 et 57.

également après n = 60, il semble se produire pour tout n. Cela pourrait être un problème de mémoire car cela fonctionne bien pour les valeurs inférieures de n.

Remarque: tout ce qui a trait à l'entier c est uniquement destiné à réduire la première boucle while. De préférence, je veux que la boucle while lise b < 251 pour me donner 250 itérations, mais je cours plutôt quelque chose comme b < 51 pour c = 1,2,3,4,5 pour obtenir 5 fichiers différents avec 50 résultats plutôt que 1 avec 250.

le code est le suivant:

#include <stdio.h> 
#include <string.h> 
#include <math.h> 
#include <iostream> 
#include <iomanip> 
#include <fstream> 
#include <time.h> 
#include <stdlib.h> 
#include <sstream> 
using namespace std; 

int main() 
{ 

    int a,b,c,f,i,j,k,m,n,s; 
    double p,Time,Averagetime,Energy,energy,Distance,Length,DotProdForce,Forcemagnitude, 
     ForceMagnitude[101],Force[101][4],E[10001],En[501],x[101][4],y[101][4]; 

    clock_t t1,t2; 
    t1=clock(); 

    b=1; 
    c=1; 
    Time=0.0; 

    while(b<251){ 

    clock_t t3,t4; 
    t3=clock(); 

    /* set the number of points */ 
    n=45; 

    /* check that there are no more than 100 points */ 
    if(n>100){ 
     cout << n << " is too many points for me :-(\n"; 
     exit(0); 
    } 

    /* reset the random number generator */ 
    srand((unsigned)time(0)); 

    for (i=1;i<=n;i++){ 
     x[i][1]=((rand()*1.0)/(1.0*RAND_MAX)-0.5)*2.0; 
     x[i][2]=((rand()*1.0)/(1.0*RAND_MAX)-0.5)*2.0; 
     x[i][3]=((rand()*1.0)/(1.0*RAND_MAX)-0.5)*2.0; 

     Length=sqrt(pow(x[i][1],2)+pow(x[i][2],2)+pow(x[i][3],2)); 

     for (k=1;k<=3;k++){ 
     x[i][k]=x[i][k]/Length; 
     } 
    } 

    /* calculate the energy */ 
    Energy=0.0; 

    for(i=1;i<=n;i++){ 
     for(j=i+1;j<=n;j++){ 
     Distance=sqrt(pow(x[i][1]-x[j][1],2)+pow(x[i][2]-x[j][2],2) 
        +pow(x[i][3]-x[j][3],2)); 

     Energy=Energy+1.0/Distance; 
     } 
    } 

    /* Save Original Points */ 
    for(i=1;i<=n;i++){ 
     y[i][1]=x[i][1]; 
     y[i][2]=x[i][2]; 
     y[i][3]=x[i][3]; 
    } 

    /* Loop for random points m times*/ 
    m=10; 

    if (m>100){ 
     cout << "The m="<< m << " loop is inefficient...lessen m \n"; 
     exit(0); 
    } 

    a=1; 

    while(a<m){ 

     /* assign random points */ 
     for (i=1;i<=n;i++){ 
     x[i][1]=((rand()*1.0)/(1.0*RAND_MAX)-0.5)*2.0; 
     x[i][2]=((rand()*1.0)/(1.0*RAND_MAX)-0.5)*2.0; 
     x[i][3]=((rand()*1.0)/(1.0*RAND_MAX)-0.5)*2.0; 

     Length=sqrt(pow(x[i][1],2)+pow(x[i][2],2)+pow(x[i][3],2)); 

     for (k=1;k<=3;k++){ 
      x[i][k]=x[i][k]/Length; 
     } 
     } 

     /* calculate the energy */ 
     energy=0.0; 

     for(i=1;i<=n;i++){ 
     for(j=i+1;j<=n;j++){ 
      Distance=sqrt(pow(x[i][1]-x[j][1],2)+pow(x[i][2]-x[j][2],2) 
         +pow(x[i][3]-x[j][3],2)); 

      energy=energy+1.0/Distance; 
     } 
     } 

     if(energy<Energy) 
     for(i=1;i<=n;i++){ 
      for(j=1;j<=3;j++){ 
      Energy=energy; 
      y[i][j]=x[i][j]; 
      } 
     } 
     else 
     for(i=1;i<=n;i++){ 
      for(j=1;j<=3;j++){ 
      energy=Energy; 
      x[i][j]=y[i][j]; 
      } 
     } 

     a=a+1; 
    } 

    /* Create string stream 1 */ 
    ostringstream String1; 
    String1 << "Bestrandonpoints_" << n; //add number 

    /* Output these points */ 
    ofstream File1 (String1.str().c_str()); 
    File1 << "Energy=" << Energy << "\n"; 
    for(i=1;i<=n;i++){ 
     File1 << x[i][1] << " " << x[i][2] << " " << x[i][3] << "\n"; 
    } 
    File1.close(); 

    /* For energy file later */ 
    E[0]=Energy; 

    /* Start doing gradient flow approach */ 
    a=1; 
    s=0; 
    f=0; 
    Forcemagnitude=1.0; 

    if(n>80) 
     p=0.005; 
    else if(n>60) 
     p=0.01; 
    else if(n>40) 
     p=0.02; 
    else 
     p=0.05; 

    while(Forcemagnitude>0.00005){ 

     /* Reset initial force and energy change */ 

     for(i=1;i<=n;i++){ 
     Force[i][1]=0.0; 
     Force[i][2]=0.0; 
     Force[i][3]=0.0; 
     } 
     /* Calculate force on each particle */ 

     for(i=1;i<=n;i++){ 
     for(j=1;j<i;j++){ 

      Distance=sqrt(pow(x[i][1]-x[j][1],2)+pow(x[i][2]-x[j][2],2) 
         +pow(x[i][3]-x[j][3],2)); 
      Force[i][1]=Force[i][1]+((x[i][1]-x[j][1])/(pow((Distance),3))); 
      Force[i][2]=Force[i][2]+((x[i][2]-x[j][2])/(pow((Distance),3))); 
      Force[i][3]=Force[i][3]+((x[i][3]-x[j][3])/(pow((Distance),3))); 
     } 

     for (j=i+1;j<=n;j++){ 

      Distance=sqrt(pow(x[i][1]-x[j][1],2)+pow(x[i][2]-x[j][2],2) 
         +pow(x[i][3]-x[j][3],2)); 
      Force[i][1]=Force[i][1]+((x[i][1]-x[j][1])/(pow((Distance),3))); 
      Force[i][2]=Force[i][2]+((x[i][2]-x[j][2])/(pow((Distance),3))); 
      Force[i][3]=Force[i][3]+((x[i][3]-x[j][3])/(pow((Distance),3))); 
     } 
     } 

     /* Add the force to my points */ 
     for(i=1;i<=n;i++){ 

     DotProdForce=Force[i][1]*x[i][1]+Force[i][2]*x[i][2]+Force[i][3]*x[i][3]; 

     y[i][1]=x[i][1]; 
     y[i][2]=x[i][2]; 
     y[i][3]=x[i][3]; 

     Force[i][1]=Force[i][1]-DotProdForce*y[i][1]; 
     Force[i][2]=Force[i][2]-DotProdForce*y[i][2]; 
     Force[i][3]=Force[i][3]-DotProdForce*y[i][3]; 

     x[i][1] = y[i][1]+p*(Force[i][1]); 
     x[i][2] = y[i][2]+p*(Force[i][2]); 
     x[i][3] = y[i][3]+p*(Force[i][3]); 

     /* Bring it back onto sphere */ 

     Length=sqrt(pow(x[i][1],2)+pow(x[i][2],2)+pow(x[i][3],2)); 

     for (j=1;j<=3;j++){ 
      x[i][j]=x[i][j]/Length; 
     } 
     } 

     /* Calculate the new energy */ 

     energy=0.0; 

     for(i=1;i<=n;i++){ 
     for(j=i+1;j<=n;j++){ 

      Distance=sqrt(pow(x[i][1]-x[j][1],2)+pow(x[i][2]-x[j][2],2) 
         +pow(x[i][3]-x[j][3],2)); 
      energy=energy+1.0/Distance; 
     } 
     } 

     E[a]=energy; 

     /* Choose best energy and therefore best points */ 
     if (energy<Energy) 
     Energy=energy,s=s+1; 
     else 
     energy=Energy,f=f+1,p=(9.5*p)/10; 

     for(i=1;i<=n;i++){ 
     ForceMagnitude[i]=pow((pow(Force[i][1],2)+pow(Force[i][2],2) 
           +pow(Force[i][3],2)),0.5); 
     } 

     for(i=1;i<=n-1;i++){ 
     if(ForceMagnitude[i]<ForceMagnitude[i+1]) 
      ForceMagnitude[i]=ForceMagnitude[i+1]; 
     else 
      ForceMagnitude[i+1]=ForceMagnitude[i]; 
     } 

     Forcemagnitude=ForceMagnitude[n]; 

     a=a+1; 
    } 

    En[b]=Energy; 

    b=b+1; 

    t4=clock(); 
    float diff ((float)t4-(float)t3); 
    float seconds = diff/CLOCKS_PER_SEC; 

    Time = Time + seconds; 

    } 

    Averagetime = Time/(b-1); 

    cout << fixed << setprecision (4) << "Average Time: " << Averagetime << "(s) \n"; 
    cout << fixed << setprecision(10) << "Energy=" << Energy << "\n"; 

    t2=clock(); 
    float diff ((float)t2-(float)t1); 
    float seconds = diff/CLOCKS_PER_SEC; 

    /* Create string stream 2 */ 
    ostringstream String2; 
    String2 << "GFPoints_" << n; //add number 

    /* Output these points */ 
    ofstream File2 (String2.str().c_str()); 
    for(i=1;i<=n;i++){ 
    File2 << x[i][1] << " " << x[i][2] << " " << x[i][3] << "\n"; 
    } 
    File2.close(); 

    /* Create string stream 3 */ 
    ostringstream String3; 
    String3 << "GFEnergies_" << n; //add number 

    /* Output these points */ 
    ofstream File3 (String3.str().c_str()); 
    for(i=1;i<a;i++){ 
    File3 << fixed << setprecision (10) << E[i] << "\n"; 
    } 
    File3.close(); 

    /* Output to help with gnuin.txt */ 
    ofstream File4 ("mypoints"); 
    for(i=1;i<=n;i++){ 
    File4 << x[i][1] << " " << x[i][2] << " " << x[i][3] << "\n"; 
    } 
    File4.close(); 

    /* Create string stream 4 */ 
    ostringstream String4; 
    String4 << "GFInfo_" << n; //add number 

    /* Output these points */ 
    ofstream File5 (String4.str().c_str()); 
    File5 << "Iterations=" << a-1 << "\n"; 
    File5 << "Successes=" << s << " Failures=" << f << "\n"; 
    File5 << fixed << setprecision(20) << "Energy=" << Energy << "\n"; 
    File5 << fixed << setprecision(5) << "Total run time: " << seconds << "(s) \n"; 
    File5 << fixed << setprecision(5) << "Average run time: " << Averagetime << "(s) \n"; 
    File5.close(); 

    /* Create string stream 5 */ 
    ostringstream String5; 
    String5 << "GF%Energies_" << n << "_" << c; //add number 

    /* Output these points */ 
    ofstream File6 (String5.str().c_str()); 
    for(i=1;i<b;i++){ 
    File6 << fixed << setprecision(20) << En[i] << "\n"; 
    } 
    File6.close(); 

    cout << fixed << setprecision(5) << "Run time: " << seconds << "(s)" << "\n"; 
    return 0; 

} 

Merci pour toute lumière que vous étalez sur le sujet, A.

Answer 1

Les problèmes évidents sont ces lignes:

E[a]=energy; 
En[b]=Energy; 

Vous incrémenter a et b à chaque itération de la boucle, mais ne les vérifie pas contre les limites du tableau fixe; donc si les boucles itèrent trop souvent, vous écrirez en dehors des tableaux.

Peut-être que vous souhaitez remplacer ceux-ci par des tableaux dynamiques (std::vector<double>), ou peut-être que vous voulez abandonner si a ou b devient trop grand.

Answer 2

Essayez de compiler avec:

-mmacosx-version-min=10.6