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#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#define M 10 /* maximum row */
#define N 10 /* maximum column */
int gauss(int m,int n,double a[][N],double x[]);
void print_matrix1(int m, double matrix[]);
void print_matrix2(int m, int n, double matrix[][N]);
int main()
{
double x[] = {1.5, 1.6, 1.7, 1.8, 1.9, 2.0};
double y[] = {0.0668, 0.0538, 0.0456, 0.0349, 0.0297, 0.022};
double z[N];
double v0 =0;
double v1 =0;
double v2 =0;
double v3 =0;
double v4 =0;
double t0 =0;
double t1 =0;
double t2 =0;
// double yhat;
FILE *file3;
int n=6;
int l;
for ( l=0; l<n; l++)
{
v0++;
v1 = v1 + x[l];
v2 = v2 + pow(x[l],2);
v3 = v3 + pow(x[l],3);
v4 = v4 + pow(x[l],4);
t0 = t0 + y[l];
t1 = t1 + x[l]*y[l];
t2 = t2 + (x[l]*x[l])*y[l];
}
double a[M][N] = {{v0, v1, v2, t0}, {v1, v2, v3, t1}, {v2, v3, v4, t2}};
int n_row = 3, n_column = 4, return_val;
printf("matrix A_C:\n");
print_matrix2( n_row, n_column, a );
return_val = gauss( n_row, n_column, a, x );
printf("matrix X:\n");
print_matrix1( n_row, x );
printf("Quad Regresion = %fx^2+%fx+%f\n",x[2],x[1],x[0]);
///////START\\\\\\\\\
//Solve for Mean of Y
double r1, r, meany, yhat, xhat;
double s =0;
double s0 =0;
int i;
meany=t0/n;
//Solve So
for(int i=0; i<n; i++)
{
s0+=pow((y[i]-meany),2);
}
//Solve S
for(i=0; i<n; i++)
{
yhat=x[2]+ x[1]*x[i] + x[0] *pow(x[i],2);
s+=pow( y[i] -yhat , 2);
}
//Solve for Corelation Coeffice
r1=(s0-s)/s0;
r=sqrt(r1);
printf("\nThe Corelation Coefft is: r= %f\n", r);
file3=fopen("Data2.txt", "w");
for(i=0; i<71; i++)
{
xhat= .01*i + 1.4;
yhat= x[2] + x[1]*xhat + x[0] *pow(xhat,2);
fprintf(file3, "(%.3f , %f)\n", xhat, yhat);
}
fclose(file3);
return 0;
}
/////END\\\\\\
int gauss(int m, int n, double a[][N], double x[])
{
int i, j, k;
/*** forward elimination ***/
for( j = 0; j < n-1; j++ )
{
for( k = j+1; k < n; k++ )
{
a[j][k] = a[j][k] / a[j][j];
}
a[j][j] = 1.0;
for( i = j+1; i < m; i++ )
{
for( k = j+1; k < n; k++ )
{
a[i][k] -= a[i][j] * a[j][k];
}
a[i][j] = 0.0;
}
}
print_matrix2( m, n, a );
/*** back substitution ***/
x[m-1] = a[m-1][m];
for( i = m-2; i >= 0; i-- )
{
x[i] = a[i][m];
for( j = m-1; j > i; j-- )
{
x[i] -= a[i][j] * x[j];
a[i][j] = 0;
}
a[i][m] = x[i];
}
print_matrix2( m, n, a );
return 0;
}
void print_matrix1(int m, double matrix[])
{
int i;
for( i = 0; i < m; i++ )
{
printf("%12.4f", matrix[i]);
printf("\n");
}
printf("\n");
getchar();
}
void print_matrix2(int m, int n, double matrix[][N])
{
int i, j;
for( i = 0; i < m; i++ )
{
for( j = 0; j < n; j++ )
{
printf("%12.4f", matrix[i][j]);
}
printf("\n");
}
printf("\n");
getchar();
for (int j=0;j<n;j++)
return 0;
}
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