anchor.diff:  
   [source]
   ----
  -./bin/elasticsearch-plugin install https://github.com/scaleborn/elasticsearch-linear-regression/releases/download/5.5.1.1/elasticsearch-linear-regression-5.5.1.1.zip
  +./bin/elasticsearch-plugin install https://github.com/scaleborn/elasticsearch-linear-regression/releases/download/5.5.1.2/elasticsearch-linear-regression-5.5.1.2.zip
   ----
   The plugin will be installed under the name "linear-regression".
   Do not forget to restart the node after installing.
  
positive.code: `rss`:: Residual sum of squares as a measure of the discrepancy between the data and the estimated model.
          The lower the `rss` number, the smaller the error of the prediction, and the better the model.
  `mse`:: Mean squared error or rather `rss` divided by the number of documents consumed for model estimation.
  `coefficients`:: Estimated coefficients
    image:http://latex.codecogs.com/gif.latex?\theta_0,%20\theta_1,%20\theta_2,%20\theta_3,.%20.%20.,%20\theta_C%20[]
      of the linear linear hypothesis function ``h(x)``.
  
negative.code:     ...
      "aggregations": {
          "house_prices": {
              "rss": 49523788338938.75,
              "mse": 63410740510.80505,
              "r2": 0.4788369924642064,
              "coefficients": [
                  47553.1873756476,
                  -100544.07258945837,
                  45981.15827544975,
                  309.6013051477474
              ]
          }
      }
  