docs: public void updateRangesFirst(Instance instance, int numAtt, double[][] ranges) {
      for (int j = 0; j < numAtt; j++) {
        if (!instance.isMissing(j)) {
          ranges[j][R_MIN] = instance.value(j);
          ranges[j][R_MAX] = instance.value(j);
          ranges[j][R_WIDTH] = 0.0;
        }
        else { // if value was missing
          ranges[j][R_MIN] = Double.POSITIVE_INFINITY;
          ranges[j][R_MAX] = -Double.POSITIVE_INFINITY;
          ranges[j][R_WIDTH] = Double.POSITIVE_INFINITY;
        }
      }
    }