Code:
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
float sum_xsquared_by_sigmasquared(float myarray[10000][4], int num_elements); //Create prototypes for summing values in file
float sum_y_by_sigmasquared(float myarray[10000][4], int num_elements);
float sum_x_by_sigmasquared(float myarray[10000][4], int num_elements);
float sum_xy_by_sigmasquared(float myarray[10000][4], int num_elements);
float sum_one_over_sigmasquared(float myarray[10000][4], int num_elements);
int main()
{
int i, c=10000, v=4; //Define
float x,y,sx,sy,myarray[c][v]; //Define Array for storage and co-ordinates
FILE *myfile; //Define a pointer to the file input
for(c=0; c<10000; c++) //Initialise Array
{
for(v=0; v<4; v++)
{
myarray[c][v]=0;
}
}
myfile=fopen("/home/sam/Documents/C Projects/LargeDataSet","r"); //Find and open File and store data
for(c=0; !feof(myfile); c++)
{
fscanf(myfile,"%f%f%f%f", &x,&sx,&y,&sy); //Read file and store data in array
myarray[c][0]=x;
myarray[c][1]=sx;
myarray[c][2]=y;
myarray[c][3]=sy;
}
float a, b, a_sigma_squared, b_sigma_squared, a_sigma, b_sigma; //Define values for output for Line
a=((sum_y_by_sigmasquared(myarray, c)*sum_xsquared_by_sigmasquared(myarray, c))-(sum_x_by_sigmasquared(myarray, c)*sum_xy_by_sigmasquared(myarray, c)))/((sum_one_over_sigmasquared(myarray, c)*sum_xsquared_by_sigmasquared(myarray, c))-pow(sum_x_by_sigmasquared(myarray, c),2));
b=((sum_one_over_sigmasquared(myarray, c)*sum_xy_by_sigmasquared(myarray, c))-(sum_x_by_sigmasquared(myarray, c)*sum_y_by_sigmasquared(myarray, c)))/((sum_one_over_sigmasquared(myarray, c)*sum_xsquared_by_sigmasquared(myarray, c))-pow(sum_x_by_sigmasquared(myarray, c),2));
a_sigma_squared=sum_xsquared_by_sigmasquared(myarray, c)/((sum_one_over_sigmasquared(myarray, c)*sum_xsquared_by_sigmasquared(myarray, c))-pow(sum_x_by_sigmasquared(myarray, c),2));
b_sigma_squared=sum_one_over_sigmasquared(myarray, c)/((sum_one_over_sigmasquared(myarray, c)*sum_xsquared_by_sigmasquared(myarray, c))-pow(sum_x_by_sigmasquared(myarray, c),2));
a_sigma=sqrt(a_sigma_squared);
b_sigma=sqrt(b_sigma_squared);
printf("The value of sum_xsquard/sigmasquared is: %f\n", sum_xsquared_by_sigmasquared(myarray, c));
printf("The value of sum_y/sigmasquared is: %f\n", sum_y_by_sigmasquared(myarray, c));
printf("The value of sum_x/sigmasquared is: %f\n", sum_x_by_sigmasquared(myarray, c));
printf("The value of sum_xy/sigmasquared is: %f\n", sum_xy_by_sigmasquared(myarray, c));
printf("The value of sum_one/sigmasquared is: %f\n\n", sum_one_over_sigmasquared(myarray, c));
printf("Y= Ax + B\n\n");
printf("Here follows the values for your Linear Least Squares variables:\n\n"); //Print Values
printf("The A Value is: %f\n", a);
printf("The error in A is: %f\n", a_sigma);
printf("The B Value is: %f\n", b);
printf("The error in B is: %f\n", b_sigma);
fclose(myfile);
return 0;
}
float sum_xsquared_by_sigmasquared(float myarray[10000][4], int num_elements) //Functions for summing values required for a and b calculation
{
int i, sum=0;
for (i=0; i<num_elements; i++)
{
sum = sum + pow(myarray[i][0],2)/pow(myarray[i][3],2);
}
return(sum);
}
float sum_y_by_sigmasquared(float myarray[10000][4], int num_elements)
{
int i, sum=0;
for (i=0; i<num_elements; i++)
{
sum = sum + myarray[i][2]/pow(myarray[i][3],2);
}
return(sum);
}
float sum_x_by_sigmasquared(float myarray[10000][4], int num_elements)
{
int i, sum=0;
for (i=0; i<num_elements; i++)
{
sum = sum + myarray[i][0]/pow(myarray[i][3],2);
}
return(sum);
}
float sum_xy_by_sigmasquared(float myarray[10000][4], int num_elements)
{
int i, sum=0;
for (i=0; i<num_elements; i++)
{
sum = sum + (myarray[i][0]*myarray[i][2])/pow(myarray[i][3],2);
}
return(sum);
}
float sum_one_over_sigmasquared(float myarray[10000][4], int num_elements)
{
int i, sum=0;
for (i=0; i<num_elements; i++)
{
sum = sum + 1/pow(myarray[i][3 ],2);
}
return(sum);
}
