Error from Matlab to C (just one line code)

Hi people. I have en error translating a function from Matlab to C/C++ :

Code:

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radius(floor(rows/2+1),floor(cols/2+1)) = 1;
 % Get rid of the 0 radius value at the 0
 % frequency point (now at top-left corner)
 % so that taking the log of the radius will
 % not cause trouble.

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What I did is:

Code:

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

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I m sure it s there the problem, because before this line I can print what I want and I can see it at run-time, but after this line I can not print nothing and the work is like blocked. Do you know the error?

Please show where you define the radius[][] array. Btw, this is the C++ forum. There's a separate forum for C questions.

Code:

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double **createmat(int rows,int cols){

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Code:

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    double **m;

    m=new double*[rows];
    for(int i=0;i<rows;i++)
        m[i]=new double[cols];

    return m;
}


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In main:

Code:

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typedef double**matriz;

matriz radius,theta;

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Both are built in a function

Given your use of new[], I take it that this is really C++, so call it C++ instead of the ambigious "C/C++" combo.

Anyway, for starters, please use std::vector or some other appropriate container instead of directly using new[], unless you have some special reasons to do so. Then, post the smallest and simplest (compilable) program that demonstrates the problem.

Hi, the problem is that before using it I used vectors of vectors and I had a problem about glibc. My teacher of University told me I have it because of vector of vectors utilization. So I used this form to do it. Also with that error we did not understand where were the error neither. Can I have an example of what you mean saying a smallest and simplest compilable program. Because to arrive where is that invocation, before there is a lot of code. Maybe I can send you the function where I have the problem.

All my project compile. But running it, it stopped in this line his work.This is the function where i have the problem:

Code:

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void pre_filter_Computations(matriz radius,matriz theta,int cols,int rows){

  double X[rows][cols],Y[rows][cols];
  double x[cols],y[rows];
  double epsilon = 0.0001;

  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]);

          }
      }
    printf("Hello\n"); // it print
    radius[rows/2][cols/2]=1;
  printf("Hello\n"); //doesn' print
      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;
          }
      }
}


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Smallest and simplest (compilable) program that demonstrates the problem means a program (ie code) that compiles, shows the problem and furthermore, it is as small as you can make it, preferably only a handful lines of code. Anything that doesn't have anything to do with the problem - get rid of it.
But honestly, if you get an error, you should try to get to the bottom of it instead of trying to recourse to C-style code. You would also do well to switch away from C constructs such as printf and C-style casts. cout is the equivalent of printf, and C++-style casts are the equivalent of C-style casts (google it).

found the error that was in the meshgrid. I mean:

Code:

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for(int m=0;m<cols;m++){
  for(int n=0;n<rows;n++){ 
    X[m][n]=x[m];     
    Y[m][n]=y[n]; 
 }
}

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Meshgrid :

Code:

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[X,Y] = meshgrid(x,y) 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.

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I had to use x vector for cols and y for rows as my teacher said me, I inverted in the innested for rows and cols, so causing a multiply of rows and cols. Now I d like to know if the meshgrid works well. Do you think is right?

Code:

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for(int m=0;m<rows;m++){
  for(int n=0;n<cols;n++){
      X[m][n]=x[m];   
      Y[m][n]=y[n];
  }
}

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Code:

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