coeffs.h

//Function declaration
double **createMat(int m,int n);
void readMat(double **p, int m,int n);
void print(double **p,int m,int n);
double **loadtxt(char *str,int m,int n);
double linalg_norm(double **a, int m);
double **linalg_sub(double **a, double **b, int m, int n);
double **linalg_inv(double **mat, int m);
double **matmul(double **a, double **b, int m, int n, int p);
double **transpose(double **a,  int m, int n);
double **linspace(double a, double l, int n);
void savetxt(double **a, char *str,int m,int n);
double **line_gen(double**A,double**B);
//End function declaration


//Defining the function for matrix creation
double **createMat(int m,int n)
{
 int i;
 double **a;
 
 //Allocate memory to the pointer
a = (double **)malloc(m * sizeof( *a));
    for (i=0; i<m; i++)
         a[i] = (double *)malloc(n * sizeof( *a[i]));

 return a;
}
//End function for matrix creation


//Defining the function for reading matrix 
void readMat(double **p, int m,int n)
{
 int i,j;
 for(i=0;i<m;i++)
 {
  for(j=0;j<n;j++)
  {
   scanf("%lf",&p[i][j]);
  }
 }
}
//End function for reading matrix

//Read  matrix from file
double **loadtxt(char *str,int m,int n)
{
FILE *fp;
double **a;
int i,j;


a = createMat(m,n);
fp = fopen(str, "r");

 for(i=0;i<m;i++)
 {
  for(j=0;j<n;j++)
  {
   fscanf(fp,"%lf",&a[i][j]);
  }
 }
//End function for reading matrix from file

fclose(fp);
 return a;

}


//Defining the function for printing
void print(double **p, int m,int n)
{
 int i,j;

 for(i=0;i<m;i++)
 {
  for(j=0;j<n;j++)
  printf("%lf ",p[i][j]);
 printf("\n");
 }
}
//End function for printing

//Defining the function for norm

double linalg_norm(double **a, int m)
{
int i;
double norm=0.0;

 for(i=0;i<m;i++)
 {
norm = norm + a[i][0]*a[i][0];
}
return sqrt(norm);

}
//End function for norm

//Defining the function for difference of matrices

double **linalg_sub(double **a, double **b, int m, int n)
{
int i, j;
double **c;
c = createMat(m,n);

 for(i=0;i<m;i++)
 {
  for(j=0;j<n;j++)
  {
c[i][j]= a[i][j]-b[i][j];
  }
 }
return c;

}
//End function for difference of matrices

//Defining the function for inverse of 2x2 matrix


double **linalg_inv(double **mat, int m)
{
double **c, det;
c = createMat(m,m);

det = mat[0][0]*mat[1][1]-mat[0][1]*mat[1][0];

c[0][0] = mat[1][1]/det;
c[0][1] = -mat[1][0]/det;
c[1][0] = -mat[0][1]/det;
c[1][1] = mat[0][0]/det;

return c;

}
// End  function for inverse of 2x2 matrix


//Defining the function for difference of matrices

double **matmul(double **a, double **b, int m, int n, int p)
{
int i, j, k;
double **c, temp =0;
c = createMat(m,p);

 for(i=0;i<m;i++)
 {
  for(k=0;k<p;k++)
  {
    for(j=0;j<n;j++)
    {
	temp= temp+a[i][j]*b[j][k];
    }
	c[i][k]=temp;
	temp = 0;
  }
 }
return c;

}
//End function for difference of matrices

//Defining the function for transpose of matrix

double **transpose(double **a,  int m, int n)
{
int i, j;
double **c;
//printf("I am here");
c = createMat(n,m);

 for(i=0;i<n;i++)
 {
  for(j=0;j<m;j++)
  {
c[i][j]= a[j][i];
//  printf("%lf ",c[i][j]);
  }
 }
return c;

}
//End function for transpose of matrix

//Linspace function
double **linspace(double a, double l, int m)
{
//Variable declarations
double d, **ap;
int i,j;

ap = createMat(m,1);

//Common difference
d = (l-a)/(m-1);

 for(i=0;i<1;i++)
 {
  for(j=0;j<m;j++)
  {
ap[j][i] = a+j*d;

  }
 }
//Returning the address of the first memory block
return ap;

}

//End linspace function

//Write matrix into file
void savetxt(double **a, char *str,int m,int n)
{
FILE *fp;
int i,j;


fp = fopen(str, "w");

 for(i=0;i<m;i++)
 {
  for(j=0;j<n;j++)
  {
   fprintf(fp,"%lf ",a[i][j]);
  }
   fprintf(fp,"\n");

 }
fclose(fp);

}
//End function for writing matrix into file


//Line generating function 


double** line_gen(double**A,double**B){
	int len=100;
	double**x_AB=createMat(2,len);
	double**lam=linspace(0,1,len);
	for (int i=0; i<len; i++){
		x_AB[0][i]=*A[0]+*lam[i]*(*B[0]-*A[0]);
		x_AB[1][i]=*A[1]+*lam[i]*(*B[1]-*A[1]);
	}
	return x_AB;
}