Thread: Error detected : glibc

Hi people I have this error entering a function:
(really the error lines are more than this I put)

Code:

*** glibc detected *** /home/elvio/workspace/aws/Debug/aws: double free or corruption (!prev): 0x0000000001eff100 ***
======= Backtrace: =========
/lib/x86_64-linux-gnu/libc.so.6(+0x7eb96)[0x7f950c739b96]
/home/elvio/workspace/aws/Debug/aws[0x40afde]
/home/elvio/workspace/aws/Debug/aws[0x40a940]
/home/elvio/workspace/aws/Debug/aws[0x409f3b]
/home/elvio/workspace/aws/Debug/aws(_ZNSt6vectorIdSaIdEED1Ev+0x42)[0x4097a0]
/home/elvio/workspace/aws/Debug/aws[0x40b4c5]

The function is : (I print Welcome to see in console I enter in the function)

Code:

void pre_filter_Computations(vector< vector<double> > radius,vector< vector<double> > theta,int cols,int rows){

  vector<double>x(cols);
  vector<double>y(rows);
  vector< vector<double> >X(cols, vector<double>(rows));
  vector< vector<double> >Y(cols, vector<double>(rows));
  double epsilon = 0.0001;

  printf("welcome\n");

  for(int i=0;i<cols;i++){
      x[i]=((double)(i-cols)/2)/((double)cols/2);
  }

  for(int z=0;z<rows;z++){
       y[z]=-(((double)(z-rows)/2)/((double)rows/2));
   }

for(int m=0;m<cols;m++){
  for(int n=0;n<rows;n++){

       X[m][n]=x[m];
       Y[m][n]=y[n];
  }
}

      for(int a=0;a<rows;a++){
            for(int b=0;b<cols;b++){

                 X[a][b] = pow(X[a][b],2);
                 Y[a][b] = pow(Y[a][b],2);
                 X[a][b] = X[a][b] + Y[a][b];
                  radius[a][b] = sqrt(X[a][b]);

          }
      }

      radius[rows/2][cols/2]=1;

      for(int a=0;a<rows;a++){
           for(int b=0;b<cols;b++){
               radius [a][b]= radius[a][b] + epsilon;
               theta[a][b] = atan2(Y[a][b],X[a][b])*180/PI;
           }
      }

}

Hi you have reason. I have to pass the pointer to the vector of vector. I just studied C and not studied C++,but worling with images I need to use it. I m trying to assign a pointer to radius and theta.
In main:

Code:

vector< vector<double> >radius(rows, vector<double>(cols); // no problem

double *radius_ptr = &radius.front(); //cannot convert vector<double>* to double*

About the function I suppose the problem is when I have to create the meshgrid, I mean when there is the 2 for innested and I create X[m][n] and Y[m][n]. the first innested for.

Whit meshgrid I mean to transforms the domain specified by vectors x and y into arrays X and Y, which can be used to evaluate functions of two variables and three-dimensional mesh/surface plots. The rows of the output array X are copies of the vector x; columns of the output array Y are copies of the vector y.

because I have to do this datas (radius,theta) conserve their values exiting the function. Googling I read I have to pass the pointers because era not dynamic. I m sorry but I just studied C and not C++ and in my project I must use a little of C++

Maybe I don t talk very well Eglish. Sorry. I just have to modify in the function the vectors. So I need that when I go back to the main that my vectors have new data, because I changed it in this function. So I need to pass a pointer I suppose.

So do I have just to pass the & operator to the function and create the vector in the main to obtain pass by reference? Don t I need to create a pointer too?

I adjust it. Thanks Elysia. But I have the glibc error to solve.