问题描述
基于之前训练过的前馈网络,我尝试使用 SHAP 来获取特征重要性。我按照文档中描述的所有步骤操作,但仍然收到以下错误
ValueError: Dimension 1 in both shapes must be equal,but are 2 and 1. Shapes are [?,2] and [?,1]
import pandas as pd
from numpy.random import randint
from keras.utils import to_categorical
from keras.models import Sequential
from keras.layers import Dense,Batchnormalization,Dropout,Activation
from keras.optimizers import Adam
import shap
# Train_x data creation
train_x = pd.DataFrame({
'v1': randint(2,20,1489),'v2': randint(50,200,'v3': randint(30,90,'v4': randint(100,150,1489)
})
# Train_y data creation
train_y = randint(0,2,1489)
# One-hot encoding as I use categorical cross-entropy
train_y = to_categorical(train_y,num_classes=2)
# Start construction of a DNN Sequential model.
model = Sequential()
# First input layer with a dropout and batch normalization layer following
model.add(Dense(256,input_dim=train_x.shape[1]))
model.add(Batchnormalization())
model.add(Activation('relu'))
model.add(Dropout(rate=0.2))
# Output layer
model.add(Dense(2))
model.add(Activation('softmax'))
# Use the Adam optimizer
optimizer = Adam(lr=0.001)
# Compile the model
model.compile(loss='categorical_crossentropy',optimizer=optimizer,metrics=['accuracy'])
model.summary()
# Fit model
hist = model.fit(train_x,train_y,epochs=100,batch_size=128,shuffle=False,verbose=2)
# SHAP calculation
explainer = shap.DeepExplainer(model,train_x)
shap_values = explainer.shap_values(train_x[:500].values)
我的输入形状为 (None,4)
,最后有一个 softmax 激活函数,有 2 个神经元,因为我将其用于二元分类。以下代码片段中的 train_x
数据是形状为 (1489,4)
的 Pandas 数据框。
我尝试更改 train_x
形状,但出现类似错误。任何帮助将不胜感激。
解决方法
请参阅以下使用 TF 进行二元分类的工作示例:
from numpy.random import randint
from tensorflow.keras.utils import to_categorical
from tensorflow.keras.models import Sequential
from tensorflow.keras.layers import Dense,BatchNormalization,Dropout,Activation
from tensorflow.keras.optimizers import Adam
import shap
import tensorflow
print(shap.__version__,"\n",tensorflow.__version__)
# Train_x data creation
train_x = pd.DataFrame({
'v1': randint(2,20,1489),'v2': randint(50,200,'v3': randint(30,90,'v4': randint(100,150,1489)
})
# Train_y data creation
train_y = randint(0,2,1489)
# One-hot encoding as I use categorical cross-entropy
train_y = to_categorical(train_y,num_classes=2)
# Start construction of a DNN Sequential model.
model = Sequential()
# First input layer with a dropout and batch normalization layer following
model.add(Dense(256,input_dim=train_x.shape[1]))
model.add(BatchNormalization())
model.add(Activation('relu'))
model.add(Dropout(rate=0.2))
# Output layer
model.add(Dense(2))
model.add(Activation('softmax'))
# Use the Adam optimizer
optimizer = Adam(lr=0.001)
# Compile the model
model.compile(loss='categorical_crossentropy',optimizer=optimizer,metrics=['accuracy'])
# model.summary()
# Fit model
hist = model.fit(train_x,train_y,epochs=100,batch_size=128,shuffle=False,verbose=0)
# SHAP calculation
shap.explainers._deep.deep_tf.op_handlers["AddV2"] = shap.explainers._deep.deep_tf.passthrough
explainer = shap.DeepExplainer(model,train_x)
shap_values = explainer.shap_values(train_x[:500].values)
shap.summary_plot(shap_values[1])
0.38.2
2.2.0
注意几点:
- 软件包版本(我相信 tf 应该低于 2.4)
- 添加
"AddV2"
(参见讨论 here)