euclid_calc.cpp

#include <iostream>
#include <vector>
#include <cmath>

using std::vector;
using std::sqrt;

float add_inp_scores(vector<float> a,
                     vector<float> b) {
  unsigned int i;
  float score = 0.0;
  for(i = 0; i < a.size(); i++) {
    score += a[i] * b[i];
  }
  return score;
}

float calc_squread_l2norm(vector<float> a) {
  unsigned int i;
  float ret = 0.f;
  for(i = 0; i < a.size(); i++) {
    ret += a[i] * a[i];
  }
  return ret;
}

void calc_euclid_score(vector<float> a, vector<float> b) {
  float score = add_inp_scores(a, b);
  float squared_a_norm = calc_squread_l2norm(a);
  float squared_b_norm = calc_squread_l2norm(b);
  std::cout << "score: " << score << std::endl;
  std::cout << "squared_a_norm" << squared_a_norm << std::endl;
  std::cout << "squared_b_norm" << squared_b_norm << std::endl;
  float d2 = squared_a_norm + squared_b_norm - 2 * score;
  std::cout << "d2: " << d2 << std::endl;
  float res = -sqrt(d2);
  std::cout << "res: " << res << std::endl;
}

int main() {
  vector<float> a(3);
  a[0] = 1.0;
  a[1] = 1.0;
  a[2] = 1.0;
  vector<float> b(3);
  b[0] = 1.00012;
  b[1] = 1.00018;
  b[2] = 1.00014;
  vector<float> c(3);
  c[0] = 1.00017;
  c[1] = 1.00012;
  c[2] = 1.00019;
  std::cout << "a, b" << std::endl;
  calc_euclid_score(a, b);
  std::cout << "b, c" << std::endl;
  calc_euclid_score(b, c);
}