segmentation fault

[vineeshvs]

#include<stdio.h>
#include<stdlib.h>
#include<math.h>
#define pi 3.14159265

int **transpose(int **x,int m,int n);
int **matrix_mul(int **m1,int **m2,int r1,int c1,int r2,int c2 );
int **dc4(int **x,int nrows,int ncolumns);

main()
{

  printf("hi");

  int nrows=80000,ncolumns=1,i,j,**x,**dc4_x,**ix,M=nrows,N=ncolumns;


  //memory allocation for x
  x = malloc(nrows * sizeof(int *));
  if(x == NULL)
    {
      printf("out of memory\n");
      return 0;
    }
  for(i = 0; i < nrows; i++)
    {
      x[i] = malloc(ncolumns * sizeof(int));
      if(x[i] == NULL)
	{
	  printf("out of memory\n");
	  return 0;
	}	  
    }
 





  printf("hi");



  //define some x(will take audio input later)
  for(i=0;i<80000;i++)
    for(j=0;j<1;j++)
    x[i][j]=rand()%3;

  for(i=0;i<8;i++)
    printf("%d \t",x[i][j]);


  //find dc4
  dc4_x=dc4(x,80000,1);

 
  //display dc4
  for(i=0;i<M;i++)
    for(j=0;j<1;j++)
      printf("%d",dc4_x[i][j]);
    


}









//FUNCTION_dc4
int **dc4(int **x,int nrows,int ncolumns)
{
  int M,N,i,j,**y,**T,**ix,**cn;
  M=nrows;
  N=ncolumns;        //directly giving the size of x (M,N). will include program to find the size of matrix later.




  //memory allocation for y,store dc4
  y = malloc(nrows * sizeof(int *));
  if(y == NULL)
    {
      printf("out of memory\n");
      return 0;
    }
  for(i = 0; i < nrows; i++)
    {
      y[i] = malloc(ncolumns * sizeof(int));
      if(y[i] == NULL)
	{
	  printf("out of memory\n");
	  return 0;
	}	  
    }








  //memory allocation for cn
  
  cn = malloc(nrows * sizeof(int *));
  if(cn == NULL)
    {
      printf("out of memory\n");
      return 0;
    }
  for(i = 0; i < nrows; i++)
    {
      cn[i] = malloc(ncolumns * sizeof(int));
      if(cn[i] == NULL)
	{
	  printf("out of memory\n");
	  return 0;
	}	  
    }





  //define cn 
  cn[0][1]=1;
  for(i=0;i<N;i++)
    for(j=2;j<M;j++)
      {
	cn[i][j]=cn[i][j-1]+2;
      }




  //find cn'(i.e. cn_transpose)
  int **cn_transpose;
  cn_transpose=transpose(cn,M,N);





  

  //find ix=cn'*cn
  ix=matrix_mul(cn_transpose,cn,M,N,N,M);


  

  //memory allocation for T
  T = malloc(M * sizeof(int *));
  if(T == NULL)
    {
      printf("out of memory\n");
      return 0;
    }

  
  for(i = 0; i < M; i++)
    {
      T[i] = malloc(M * sizeof(int));
      if(T[i] == NULL)
	{
	  printf("out of memory\n");
	  return 0;
	}
    }









  //define T
  for(i=0;i<M;i++)
    for(j=0;j<M;j++)
      T[i][j]=(1/sqrt(M/2))*cos((pi*ix[i][j])/(4*M));







  //find dc4
  y=matrix_mul(T,x,M,M,M,1);

  //return dc4
  return y;
}





	







  //FUNCTION_transpose
  int **transpose(int **x,int m,int n)
  {
    int nrows=n,ncolumns=m,i,j;

    //memory allocation for y,to store transpose
    int **y;
    y = malloc(nrows * sizeof(int *));
    if(y == NULL)
      {
	printf("out of memory\n");
	return 0;
      }
    for(i = 0; i < nrows; i++)
      {
	y[i] = malloc(ncolumns * sizeof(int));
	if(y[i] == NULL)
	  {
	    printf("out of memory\n");
	    return 0;
	  }	  
      }




 
    for(i=0;i<m;i++)
      for(j=0;j<n;j++)
	{
	  y[i][j]=x[j][i];
	}
    return y;
  }






  

  //FUNCTION_matrix_mul
  int **matrix_mul(int **m1,int **m2,int r1,int c1,int r2,int c2 )
  {
    int i,j,k;



    //memory allocation to store product
    int **p;
    p = malloc(r1 * sizeof(int *));
    if(p == NULL)
      {
	printf("out of memory\n");
	return 0;
      }
    for(i = 0; i < r1; i++)
      {
	p[i] = malloc(c2 * sizeof(int));
	if(p[i] == NULL)
	  {
	    printf("out of memory\n");
	    return 0;
	  }	  
      }



    //product

    for(i=0;i<r1;i++)
      {
	for(j=0;j<c2;j++)
	  {
	    p[i][j]=0;
	    for(k=0;k<r2;k++)
	      {
		p[i][j]=p[i][j]+(m1[i][k]*m2[k][j]);
	      }
	  }
      }


    return p;
  }

segmentation fault comes. cant detect any errors . help please

[Banfa]

You have some many blank lines it makes your code much longer than required and so less readable.

You have redundant duplicate variables, for example M in dc4 is just a copy of nrows, however neither variable is ever changed so one of them is redundant.

However I believe your error is actually on line 244 of your posted code, work through the logic of your own program.

[vineeshvs]

sorry for being rude and make you work for my code.Thank you, problem was there in 244th itself.
my corrected working code is also posted below.

#include<stdio.h>
#include<stdlib.h>
#include<math.h>
#define pi 3.14159265
double **transpose(double **x,int m,int n);
double **matrix_mul(double **m1,double **m2,int r1,int c1,int r2,int c2);
double **dc4(double **x,int M,int N);
main()
{
  int i,j,M=8,N=1;
  double **x,**dc4_x;
  //memory allocation for x
  x = (double**)malloc(M * sizeof(double *));
  if(x == NULL)
    {
      printf("out of memory\n");
      return 0;
    }
  for(i = 0; i < M; i++)
    {
      x[i] = (double*)malloc(N * sizeof(double));
      if(x[i] == NULL)
  	{
  	  printf("out of memory\n");
  	  return 0;
  	}
    }
  //define some x(will take audio input later)
  printf("x= \n");
  for(i=0;i<M;i++)
    {
      printf("\n");
      for(j=0;j<N;j++)
	{
	  x[i][j]=rand()%3;
	  printf("%f\t",x[i][j]);
	}
    }
  printf("\n");
  //call dc4
  dc4_x=dc4(x,M,N);
  //print dc4
  printf("dc4=\n");
  for(i=0;i<M;i++)
    {
      printf("\n");
      for(j=0;j<M;j++)
	{
	  printf("%f\t",dc4_x[i][j]);
	}
    }
  printf("\n");
}
//FUNCTION_transpose
double **transpose(double **x,int M,int N)
{
  int nrows=N,ncolumns=M,i,j;
  double **y;
  //memory allocation for y,to store transpose
  y = (double**)malloc(nrows * sizeof(double *));
  if(y == NULL)
    {
      printf("out of memory\n");
      return 0;
    }
  for(i = 0; i < nrows; i++)
    {
      y[i] = (double*)malloc(ncolumns * sizeof(double));
      if(y[i] == NULL)
	{
	  printf("out of memory\n");
	  return 0;
	}	  
    }
  //taking transpose
  for(i=0;i<N;i++)
    for(j=0;j<M;j++)
      {
	y[i][j]=x[j][i];
      }
  return y;
}
//FUNCTION_matrix_mul
double **matrix_mul(double **m1,double **m2,int r1,int c1,int r2,int c2)
{
  int i,j,k;
  double**p;
  //memory allocation to store product
  p = (double**)malloc(r1 * sizeof(double *));
  if(p == NULL)
    {
      printf("out of memory\n");
      return 0;
    }
  for(i = 0; i < r1; i++)
    {
      p[i] = (double*)malloc(c2 * sizeof(double));
      if(p[i] == NULL)
	{
	  printf("out of memory\n");
	  return 0;
	}	  
    }
  //find product of matrices
  for(i=0;i<r1;i++)
    {
      for(j=0;j<c2;j++)
	{
	  p[i][j]=0;
	  for(k=0;k<r2;k++)
	    {
	      p[i][j]=p[i][j]+(m1[i][k]*m2[k][j]);
	    }
	}
    }
  return p;
} 
//FUNCTION_dc4
double **dc4(double **x,int M,int N)
{
  int i,j;
  double **T,**cn,**ix,**y;
  //memory allocation for cn
  cn = (double**)malloc(N * sizeof(double *));
  if(cn == NULL)
    {
      printf("out of memory\n");
      return 0;
    }
  for(i = 0; i < N; i++)
    {
      cn[i] = (double*)malloc(M * sizeof(double));
      if(cn[i] == NULL)
  	{
  	  printf("out of memory\n");
  	  return 0;
  	}
    }
  //define cn
  printf("cn=\n");
  cn[0][0]=1;
  for(i=0;i<N;i++)
    {
      printf("\n");
      for(j=1;j<M;j++)
	{
	  cn[i][j]=cn[i][j-1]+2;
	  printf("%f\t",cn[i][j]);
	}
    }
  printf("\n");
  //find cn'(i.e. cn_transpose)
  double **cn_transpose;
  cn_transpose=transpose(cn,N,M);
  //print cn_transpose
  printf("cn_transpose=\n");
  for(i=0;i<M;i++)
    {
      printf("\n");
      for(j=0;j<N;j++)
	{
	  printf("%f\t",cn_transpose[i][j]);
	}
    }
  printf("\n");
  //find ix=cn'*cn
  ix=matrix_mul(cn_transpose,cn,M,N,N,M);
  //print ix
  printf("ix=\n");
  for(i=0;i<M;i++)
    {
      printf("\n");
      for(j=0;j<M;j++)
	{
	  printf("%f\t",ix[i][j]);
	}
    }
  printf("\n");
  //memory allocation for T
  T = (double**)malloc(M * sizeof(double *));
  if(T == NULL)
    {
      printf("out of memory\n");
      return 0;
    }
  for(i = 0; i < M; i++)
    {
      T[i] = malloc(M * sizeof(double));
      if(T[i] == NULL)
  	{
  	  printf("out of memory\n");
  	  return 0;
  	}
    }
  //define & print T
  printf("T=\n");
  for(i=0;i<M;i++)
    {
      printf("\n");
      for(j=0;j<M;j++)
	{
	  T[i][j]=(1/sqrt(M/2))*cos((pi*ix[i][j])/(4*M));
	  printf("%f\t",T[i][j]);	  
	}
    }
  printf("\n");   
  //find dc4
  y=matrix_mul(T,x,M,M,M,1);
  return y;     
}