add flexibility on vertical center line label

pcmdi_metrics/graphics/parallel_coordinate_plot/parallel_coordinate_plot_lib.py

@@ -39,6 +39,7 @@ def parallel_coordinate_plot(
  fill_between_lines_colors=("green", "red"),
  vertical_center=None,
  vertical_center_line=False,
+ vertical_center_line_label=None,
 ):
  """
  Parameters
@@ -74,6 +75,7 @@ def parallel_coordinate_plot(
  - `fill_between_lines_colors`: tuple or list containing two strings for colors filled between the two lines. Default=('green', 'red')
  - `vertical_center`: string ("median", "mean")/float/integer, default=None, adjust range of vertical axis to set center of vertical axis as median, mean, or given number
  - `vertical_center_line`: bool, default=False, show median as line
+ - `vertical_center_line_label`: str, default=None, label in legend for the horizontal vertical center line. If not given, it will be automatically assigned. It can be turned off by "off"
 
  Return
  ------
@@ -227,8 +229,12 @@ def parallel_coordinate_plot(
  clip_on=False,
  )
 
- if vertical_center_line: 
- ax.plot(range(N), zs_middle, "-", c="k", label="median", lw=1)
+ if vertical_center_line:
+ if vertical_center_line_label is None:
+ vertical_center_line_label = str(vertical_center)
+ elif vertical_center_line_label == "off":
+ vertical_center_line_label = None 
+ ax.plot(range(N), zs_middle, "-", c="k", label=vertical_center_line_label, lw=1)
 
  # Fill between lines
  if fill_between_lines and (comparing_models is not None):
@@ -340,7 +346,10 @@ def _data_transform(
  zs[:, 0] = ys[:, 0]
  zs[:, 1:] = (ys[:, 1:] - ymins[1:]) / dys[1:] * dys[0] + ymins[0]
 
- zs_middle = (ymids[:] - ymins[:]) / dys[:] * dys[0] + ymins[0]
+ if vertical_center is not None:
+ zs_middle = (ymids[:] - ymins[:]) / dys[:] * dys[0] + ymins[0]
+ else:
+ zs_middle = (ymaxs[:] - ymins[:]) / 2 / dys[:] * dys[0] + ymins[0]
 
  if model_names2 is not None:
  print("Models in the second group:", model_names2)