// of statistical moments.
void estimate_musigma(vector<pair<double, double> > &curve, double &mu_result, double &sigma_result)
{
- double sum_area = 0.0;
- double ex = 0.0;
- double ex2 = 0.0;
-
- for (unsigned i = 1; i < curve.size(); ++i) {
- double x1 = curve[i].first;
- double x0 = curve[i-1].first;
- double y1 = curve[i].second;
- double y0 = curve[i-1].second;
- double xm = 0.5 * (x0 + x1);
- double ym = 0.5 * (y0 + y1);
- sum_area += (x1-x0) * ym;
- ex += (x1-x0) * xm * ym;
- ex2 += (x1-x0) * xm * xm * ym;
+ double h = (curve.back().first - curve.front().first) / (curve.size() - 1);
+
+ double area = curve.front().second;
+ double ex = curve.front().first * curve.front().second;
+ double ex2 = curve.front().first * curve.front().first * curve.front().second;
+
+ for (unsigned i = 1; i < curve.size() - 1; i += 2) {
+ double x = curve[i].first;
+ double y = curve[i].second;
+ area += 4.0 * y;
+ ex += 4.0 * x * y;
+ ex2 += 4.0 * x * x * y;
}
+ for (unsigned i = 2; i < curve.size() - 1; i += 2) {
+ double x = curve[i].first;
+ double y = curve[i].second;
+ area += 2.0 * y;
+ ex += 2.0 * x * y;
+ ex2 += 2.0 * x * x * y;
+ }
+
+ area += curve.back().second;
+ ex += curve.back().first * curve.back().second;
+ ex2 += curve.back().first * curve.back().first * curve.back().second;
- ex /= sum_area;
- ex2 /= sum_area;
+ area = (h/3.0) * area;
+ ex = (h/3.0) * ex / area;
+ ex2 = (h/3.0) * ex2 / area;
mu_result = ex;
sigma_result = sqrt(ex2 - ex * ex);
sigma_result = sigma;
}
-int main(int argc, char **argv)
+void compute_new_rating(double mu1, double sigma1, double mu2, double sigma2, int score1, int score2, double &mu, double &sigma)
{
- double mu1 = atof(argv[1]);
- double sigma1 = atof(argv[2]);
- double mu2 = atof(argv[3]);
- double sigma2 = atof(argv[4]);
- int score1 = atoi(argv[5]);
- int score2 = atoi(argv[6]);
vector<pair<double, double> > curve;
if (score1 == 10) {
}
}
- double mu_est, sigma_est, mu, sigma;
+ double mu_est, sigma_est;
normalize(curve);
estimate_musigma(curve, mu_est, sigma_est);
least_squares(curve, mu_est, sigma_est, mu, sigma);
+}
+
+int main(int argc, char **argv)
+{
+ double mu1 = atof(argv[1]);
+ double sigma1 = atof(argv[2]);
+ double mu2 = atof(argv[3]);
+ double sigma2 = atof(argv[4]);
+ int score1 = atoi(argv[5]);
+ int score2 = atoi(argv[6]);
+ double mu, sigma;
+ compute_new_rating(mu1, sigma1, mu2, sigma2, score1, score2, mu, sigma);
printf("%f %f\n", mu, sigma);
}
+