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shap--shap/shap/plots/_force_matplotlib.py
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2026-07-13 13:22:52 +08:00

421 lines
13 KiB
Python

import matplotlib
import matplotlib.pyplot as plt
import numpy as np
from matplotlib import lines
from matplotlib.font_manager import FontProperties
from matplotlib.patches import PathPatch
from matplotlib.path import Path
def draw_bars(out_value, features, feature_type, width_separators, width_bar):
"""Draw the bars and separators."""
rectangle_list = []
separator_list = []
pre_val = out_value
for index, feature_values in enumerate(features):
if feature_type == "positive":
left_bound = float(feature_values[0])
right_bound = pre_val
pre_val = left_bound
separator_indent = np.abs(width_separators)
separator_pos = left_bound
colors = ["#FF0D57", "#FFC3D5"]
else:
left_bound = pre_val
right_bound = float(feature_values[0])
pre_val = right_bound
separator_indent = -np.abs(width_separators)
separator_pos = right_bound
colors = ["#1E88E5", "#D1E6FA"]
# Create rectangle
if index == 0:
if feature_type == "positive":
points_rectangle = [
[left_bound, 0],
[right_bound, 0],
[right_bound, width_bar],
[left_bound, width_bar],
[left_bound + separator_indent, (width_bar / 2)],
]
else:
points_rectangle = [
[right_bound, 0],
[left_bound, 0],
[left_bound, width_bar],
[right_bound, width_bar],
[right_bound + separator_indent, (width_bar / 2)],
]
else:
points_rectangle = [
[left_bound, 0],
[right_bound, 0],
[right_bound + separator_indent * 0.90, (width_bar / 2)],
[right_bound, width_bar],
[left_bound, width_bar],
[left_bound + separator_indent * 0.90, (width_bar / 2)],
]
line = plt.Polygon(points_rectangle, closed=True, fill=True, facecolor=colors[0], linewidth=0)
rectangle_list += [line]
# Create separator
points_separator = [
[separator_pos, 0],
[separator_pos + separator_indent, (width_bar / 2)],
[separator_pos, width_bar],
]
line = plt.Polygon(points_separator, closed=None, fill=None, edgecolor=colors[1], lw=3)
separator_list += [line]
return rectangle_list, separator_list
def draw_labels(
fig, ax, out_value, features, feature_type, offset_text, total_effect=0, min_perc=0.05, text_rotation=0
):
start_text = out_value
pre_val = out_value
# Define variables specific to positive and negative effect features
if feature_type == "positive":
colors = ["#FF0D57", "#FFC3D5"]
alignment = "right"
sign = 1
else:
colors = ["#1E88E5", "#D1E6FA"]
alignment = "left"
sign = -1
# Draw initial line
if feature_type == "positive":
x, y = np.array([[pre_val, pre_val], [0, -0.18]])
line = lines.Line2D(x, y, lw=1.0, alpha=0.5, color=colors[0])
line.set_clip_on(False)
ax.add_line(line)
start_text = pre_val
box_end = out_value
val = out_value
for feature in features:
# Exclude all labels that do not contribute at least 10% to the total
feature_contribution = np.abs(float(feature[0]) - pre_val) / np.abs(total_effect)
if feature_contribution < min_perc:
break
# Compute value for current feature
val = float(feature[0])
# Draw labels.
if feature[1] == "":
text = feature[2]
else:
text = feature[2] + " = " + feature[1]
if text_rotation != 0:
va_alignment = "top"
else:
va_alignment = "baseline"
text_out_val = plt.text(
start_text - sign * offset_text,
-0.15,
text,
fontsize=12,
color=colors[0],
horizontalalignment=alignment,
va=va_alignment,
rotation=text_rotation,
)
text_out_val.set_bbox(dict(facecolor="none", edgecolor="none"))
# We need to draw the plot to be able to get the size of the
# text box
fig.canvas.draw()
box_size = text_out_val.get_bbox_patch().get_extents().transformed(ax.transData.inverted())
if feature_type == "positive":
box_end_ = box_size.get_points()[0][0]
else:
box_end_ = box_size.get_points()[1][0]
# Create end line
if (sign * box_end_) > (sign * val):
x, y = np.array([[val, val], [0, -0.18]])
line = lines.Line2D(x, y, lw=1.0, alpha=0.5, color=colors[0])
line.set_clip_on(False)
ax.add_line(line)
start_text = val
box_end = val
else:
box_end = box_end_ - sign * offset_text
x, y = np.array([[val, box_end, box_end], [0, -0.08, -0.18]])
line = lines.Line2D(x, y, lw=1.0, alpha=0.5, color=colors[0])
line.set_clip_on(False)
ax.add_line(line)
start_text = box_end
# Update previous value
pre_val = float(feature[0])
# Create line for labels
extent_shading = [out_value, box_end, 0, -0.31]
path = [[out_value, 0], [pre_val, 0], [box_end, -0.08], [box_end, -0.2], [out_value, -0.2], [out_value, 0]]
path = Path(path)
patch = PathPatch(path, facecolor="none", edgecolor="none")
ax.add_patch(patch)
# Extend axis if needed
lower_lim, upper_lim = ax.get_xlim()
if box_end < lower_lim:
ax.set_xlim(box_end, upper_lim)
if box_end > upper_lim:
ax.set_xlim(lower_lim, box_end)
# Create shading
if feature_type == "positive":
colors = np.array([(255, 13, 87), (255, 255, 255)]) / 255.0
else:
colors = np.array([(30, 136, 229), (255, 255, 255)]) / 255.0
cm = matplotlib.colors.LinearSegmentedColormap.from_list("cm", colors)
_, Z2 = np.meshgrid(np.linspace(0, 10), np.linspace(-10, 10))
im = plt.imshow(
Z2,
interpolation="quadric",
cmap=cm,
vmax=0.01,
alpha=0.3,
origin="lower",
extent=extent_shading,
clip_path=patch,
clip_on=True,
aspect="auto",
)
im.set_clip_path(patch)
return fig, ax
def format_data(data):
"""Format data."""
# Format negative features
neg_features = np.array(
[
[data["features"][x]["effect"], data["features"][x]["value"], data["featureNames"][x]]
for x in data["features"].keys()
if data["features"][x]["effect"] < 0
]
)
neg_features = np.array(sorted(neg_features, key=lambda x: float(x[0]), reverse=False))
# Format positive features
pos_features = np.array(
[
[data["features"][x]["effect"], data["features"][x]["value"], data["featureNames"][x]]
for x in data["features"].keys()
if data["features"][x]["effect"] >= 0
]
)
pos_features = np.array(sorted(pos_features, key=lambda x: float(x[0]), reverse=True))
# Define link function
if data["link"] == "identity":
def convert_func(x):
return x
elif data["link"] == "logit":
def convert_func(x):
return 1 / (1 + np.exp(-x))
else:
emsg = f"ERROR: Unrecognized link function: {data['link']}"
raise ValueError(emsg)
# Convert negative feature values to plot values
neg_val = data["outValue"]
for i in neg_features:
val = float(i[0])
neg_val = neg_val + np.abs(val)
i[0] = convert_func(neg_val)
if len(neg_features) > 0:
total_neg = np.max(neg_features[:, 0].astype(float)) - np.min(neg_features[:, 0].astype(float))
else:
total_neg = 0
# Convert positive feature values to plot values
pos_val = data["outValue"]
for i in pos_features:
val = float(i[0])
pos_val = pos_val - np.abs(val)
i[0] = convert_func(pos_val)
if len(pos_features) > 0:
total_pos = np.max(pos_features[:, 0].astype(float)) - np.min(pos_features[:, 0].astype(float))
else:
total_pos = 0
# Convert output value and base value
data["outValue"] = convert_func(data["outValue"])
data["baseValue"] = convert_func(data["baseValue"])
return neg_features, total_neg, pos_features, total_pos
def draw_output_element(out_name, out_value, ax):
# Add output value
x, y = np.array([[out_value, out_value], [0, 0.24]])
line = lines.Line2D(x, y, lw=2.0, color="#F2F2F2")
line.set_clip_on(False)
ax.add_line(line)
font0 = FontProperties()
font = font0.copy()
font.set_weight("bold")
text_out_val = plt.text(
out_value, 0.25, f"{out_value:.2f}", fontproperties=font, fontsize=14, horizontalalignment="center"
)
text_out_val.set_bbox(dict(facecolor="white", edgecolor="white"))
text_out_val = plt.text(out_value, 0.33, out_name, fontsize=12, alpha=0.5, horizontalalignment="center")
text_out_val.set_bbox(dict(facecolor="white", edgecolor="white"))
def draw_base_element(base_value, ax):
x, y = np.array([[base_value, base_value], [0.13, 0.25]])
line = lines.Line2D(x, y, lw=2.0, color="#F2F2F2")
line.set_clip_on(False)
ax.add_line(line)
text_out_val = plt.text(base_value, 0.33, "base value", fontsize=12, alpha=0.5, horizontalalignment="center")
text_out_val.set_bbox(dict(facecolor="white", edgecolor="white"))
def draw_higher_lower_element(out_value, offset_text):
plt.text(out_value - offset_text, 0.405, "higher", fontsize=13, color="#FF0D57", horizontalalignment="right")
plt.text(out_value + offset_text, 0.405, "lower", fontsize=13, color="#1E88E5", horizontalalignment="left")
plt.text(out_value, 0.4, r"$\leftarrow$", fontsize=13, color="#1E88E5", horizontalalignment="center")
plt.text(out_value, 0.425, r"$\rightarrow$", fontsize=13, color="#FF0D57", horizontalalignment="center")
def update_axis_limits(ax, total_pos, pos_features, total_neg, neg_features, base_value, out_value):
ax.set_ylim(-0.5, 0.15)
padding = np.max([np.abs(total_pos) * 0.2, np.abs(total_neg) * 0.2])
if len(pos_features) > 0:
min_x = min(np.min(pos_features[:, 0].astype(float)), base_value) - padding
else:
min_x = out_value - padding
if len(neg_features) > 0:
max_x = max(np.max(neg_features[:, 0].astype(float)), base_value) + padding
else:
max_x = out_value + padding
ax.set_xlim(min_x, max_x)
plt.tick_params(top=True, bottom=False, left=False, right=False, labelleft=False, labeltop=True, labelbottom=False)
plt.locator_params(axis="x", nbins=12)
for key, spine in zip(plt.gca().spines.keys(), plt.gca().spines.values()):
if key != "top":
spine.set_visible(False)
def draw_additive_plot(data, figsize, show, text_rotation=0, min_perc=0.05):
"""Draw additive plot."""
# Turn off interactive plot
if show is False:
plt.ioff()
# Format data
neg_features, total_neg, pos_features, total_pos = format_data(data)
# Compute overall metrics
base_value = data["baseValue"]
out_value = data["outValue"]
offset_text = (np.abs(total_neg) + np.abs(total_pos)) * 0.04
# Define plots
fig, ax = plt.subplots(figsize=figsize)
# Compute axis limit
update_axis_limits(ax, total_pos, pos_features, total_neg, neg_features, base_value, out_value)
# Define width of bar
width_bar = 0.1
width_separators = (ax.get_xlim()[1] - ax.get_xlim()[0]) / 200
# Create bar for negative shap values
rectangle_list, separator_list = draw_bars(out_value, neg_features, "negative", width_separators, width_bar)
for i in rectangle_list:
ax.add_patch(i)
for i in separator_list:
ax.add_patch(i)
# Create bar for positive shap values
rectangle_list, separator_list = draw_bars(out_value, pos_features, "positive", width_separators, width_bar)
for i in rectangle_list:
ax.add_patch(i)
for i in separator_list:
ax.add_patch(i)
# Add labels
total_effect = np.abs(total_neg) + total_pos
fig, ax = draw_labels(
fig,
ax,
out_value,
neg_features,
"negative",
offset_text,
total_effect,
min_perc=min_perc,
text_rotation=text_rotation,
)
fig, ax = draw_labels(
fig,
ax,
out_value,
pos_features,
"positive",
offset_text,
total_effect,
min_perc=min_perc,
text_rotation=text_rotation,
)
# higher lower legend
draw_higher_lower_element(out_value, offset_text)
# Add label for base value
draw_base_element(base_value, ax)
# Add output label
out_names = data["outNames"][0]
draw_output_element(out_names, out_value, ax)
# Scale axis
if data["link"] == "logit":
plt.xscale("logit")
ax.xaxis.set_major_formatter(matplotlib.ticker.ScalarFormatter())
ax.ticklabel_format(style="plain")
if show:
plt.show()
else:
return plt.gcf()