我是TensorFlow框架的新手,正在尝试使用TensorFlow来预测基于Titanic数据集的幸存者:https://www.kaggle.com/c/titanic/data。
import tensorflow as tf
import numpy as np
import pandas as pd
from sklearn.model_selection import train_test_split
#%%
titanictrain = pd.read_csv('train.csv')
titanictest = pd.read_csv('test.csv')
df = pd.concat([titanictrain,titanictest],join='outer',keys='PassengerId',sort=False,ignore_index=True).drop(['Name'],1)
#%%
def preprocess(df):
df['Fare'].fillna(value=df.groupby('Pclass')['Fare'].transform('median'),inplace=True)
df['Fare'] = df['Fare'].map(lambda x: np.log(x) if x>0 else 0)
df['Embarked'].fillna(value=df['Embarked'].mode()[0],inplace=True)
df['CabinAlphabet'] = df['Cabin'].str[0]
categories_to_one_hot = ['Pclass','Sex','Embarked','CabinAlphabet']
df = pd.get_dummies(df,columns=categories_to_one_hot,drop_first=True)
return df
df = preprocess(df)
df = df.drop(['PassengerId','Ticket','Cabin','Survived'],1)
titanic_trainandval = df.iloc[:len(titanictrain)]
titanic_test = df.iloc[len(titanictrain):] #test after preprocessing
titanic_test.head()
# split train into training and validation set
labels = titanictrain['Survived']
y = labels.values
test = titanic_test.copy() # real test sets
print(len(test), 'test examples')
这里我正在尝试对数据进行预处理:
1.删除名称列并在训练集和测试集上进行独热编码
2.为了简单起见,删除 ['PassengerId','Ticket','Cabin','Survived']。
- 按原始顺序拆分训练集和测试集
"""# model training"""
from tensorflow.keras.layers import Input, Dense, Activation,Dropout
from tensorflow.keras.models import Model
X = titanic_trainandval.copy()
input_layer = Input(shape=(X.shape[1],))
dense_layer_1 = Dense(10, activation='relu')(input_layer)
dense_layer_2 = Dense(5, activation='relu')(dense_layer_1)
output = Dense(1, activation='softmax',name = 'predictions')(dense_layer_2)
model = Model(inputs=input_layer, outputs=output)
base_learning_rate = 0.0001
model.compile(loss=tf.keras.losses.BinaryCrossentropy(from_logits=True), optimizer=tf.keras.optimizers.Adam(lr=base_learning_rate), metrics=['acc'])
history = model.fit(X, y, batch_size=5, epochs=20, verbose=2, validation_split=0.1,shuffle = False)
submission = pd.DataFrame()
submission['PassengerId'] = titanictest['PassengerId']
然后我将训练集X放入模型中得到结果。然而,历史记录显示以下结果:
无论我如何改变学习率和批量大小,结果都不会改变,损失始终为“nan”,基于测试集的预测也始终为“nan”。
有人能解释一下问题出在哪里并提供一些可能的解决方案吗?