square_means_error.js

const adjustParams = (period) => {
      const iter = 10;
      const incr = 1 / iter;
      let bestAlpha = 0.0;
      let bestError = -1;
      let alpha = bestAlpha;
      let bestGamma = 0.0;
      let gamma = bestGamma;
      let bestDelta = 0.0;
      let delta = bestDelta;

      while (alpha < 1) {
        while (gamma < 1) {
          while (delta < 1) {
            const pred = this.predict(data, alpha, delta, gamma, period);
            const error = this.computeMeanSquaredError(data, pred);
            if (error < bestError || bestError === -1) {
              bestAlpha = alpha;
              bestGamma = gamma;
              bestDelta = delta;
              bestError = error;
            }
            delta += incr;
          }
          delta = 0;
          gamma += incr;
        }
        gamma = 0;
        alpha += incr;
      }
      alpha = bestAlpha;
      gamma = bestGamma;
      delta = bestDelta;
      return {
        alpha,
        gamma,
        delta,
        bestError,
      };
    };