static void regression_analysis(int n,bool bXYdy,real *x,real **val)
{
real S,chi2,a,b,da,db,r=0;
printf("Fitting data to a function f(x) = ax + b\n");
printf("Minimizing residual chi2 = Sum_i w_i [f(x_i) - y_i]2\n");
printf("Error estimates will be given if w_i (sigma) values are given\n");
printf("(use option -xydy).\n\n");
if (bXYdy)
lsq_y_ax_b_error(n,x,val[0],val[1],&a,&b,&da,&db,&r,&S);
else
lsq_y_ax_b(n,x,val[0],&a,&b,&r,&S);
chi2 = sqr((n-2)*S);
printf("Chi2 = %g\n",chi2);
printf("S (Sqrt(Chi2/(n-2)) = %g\n",S);
printf("Correlation coefficient = %.1f%%\n",100*r);
printf("\n");
if (bXYdy) {
printf("a = %g +/- %g\n",a,da);
printf("b = %g +/- %g\n",b,db);
}
else {
printf("a = %g\n",a);
printf("b = %g\n",b);
}
}
static void regression_analysis(int n, gmx_bool bXYdy,
real *x, int nset, real **val)
{
real S, chi2, a, b, da, db, r = 0;
int ok;
if (bXYdy || (nset == 1))
{
printf("Fitting data to a function f(x) = ax + b\n");
printf("Minimizing residual chi2 = Sum_i w_i [f(x_i) - y_i]2\n");
printf("Error estimates will be given if w_i (sigma) values are given\n");
printf("(use option -xydy).\n\n");
if (bXYdy)
{
if ((ok = lsq_y_ax_b_error(n, x, val[0], val[1], &a, &b, &da, &db, &r, &S)) != estatsOK)
{
gmx_fatal(FARGS, "Error fitting the data: %s",
gmx_stats_message(ok));
}
}
else
{
if ((ok = lsq_y_ax_b(n, x, val[0], &a, &b, &r, &S)) != estatsOK)
{
gmx_fatal(FARGS, "Error fitting the data: %s",
gmx_stats_message(ok));
}
}
chi2 = sqr((n-2)*S);
printf("Chi2 = %g\n", chi2);
printf("S (Sqrt(Chi2/(n-2)) = %g\n", S);
printf("Correlation coefficient = %.1f%%\n", 100*r);
printf("\n");
if (bXYdy)
{
printf("a = %g +/- %g\n", a, da);
printf("b = %g +/- %g\n", b, db);
}
else
{
printf("a = %g\n", a);
printf("b = %g\n", b);
}
}
else
{
double chi2, *a, **xx, *y;
int i, j;
snew(y, n);
snew(xx, nset-1);
for (j = 0; (j < nset-1); j++)
{
snew(xx[j], n);
}
for (i = 0; (i < n); i++)
{
y[i] = val[0][i];
for (j = 1; (j < nset); j++)
{
xx[j-1][i] = val[j][i];
}
}
snew(a, nset-1);
chi2 = multi_regression(NULL, n, y, nset-1, xx, a);
printf("Fitting %d data points in %d sets\n", n, nset-1);
printf("chi2 = %g\n", chi2);
printf("A =");
for (i = 0; (i < nset-1); i++)
{
printf(" %g", a[i]);
sfree(xx[i]);
}
printf("\n");
sfree(xx);
sfree(y);
sfree(a);
}
}
