| 42 | /// https://en.wikipedia.org/wiki/Kahan_summation_algorithm#Further_enhancements |
| 43 | template <typename Range = std::initializer_list<double>> |
| 44 | double NeumaierSum(Range&& inputs) { |
| 45 | double sum = 0, c = 0; |
| 46 | for (const double v : inputs) { |
| 47 | double t = sum + v; |
| 48 | if (std::isfinite(t)) { |
| 49 | if (std::abs(sum) >= std::abs(v)) { |
| 50 | // If sum is bigger, low-order digits of v are lost... |
| 51 | c += (sum - t) + v; |
| 52 | } else { |
| 53 | // ... else low-order digits of sum are lost. |
| 54 | c += (v - t) + sum; |
| 55 | } |
| 56 | } |
| 57 | sum = t; |
| 58 | } |
| 59 | return sum + c; |
| 60 | } |
| 61 | |
| 62 | /// Based-2 logarithm that works only on powers of two. |
| 63 | template <typename T> |