code: function distanceFrom(Centroids) {
                  var distances = [];
  
                  for(var i = 1; i <= this.Observations.rows(); i++) {
                      var distance = [];
  
                      for(var j = 1; j <= Centroids.rows(); j++) {
                          distance.push(this.Observations.row(i).distanceFrom(Centroids.row(j)));
                      }
  
                      distances.push(distance);
                  }
  
                  return $M(distances);
              }
docs: get the euclidian distance between the feature data X and a given centroid matrix C.