我一直在閱讀Keras文檔建立一個實現MLP反向傳播我自己的MLP網絡。我熟悉sklearn MLPClassifier,但我想學Keras
深學習。以下是第一次嘗試。該網絡有3層1輸入(功能= 64),1輸出和1隱藏。總數是(64,64,1)。輸入是125K樣本(64 DIM)和y
numpy
矩陣X
是1D numpy
二進制類(1,-1):不一致的結果sklearn
# Keras imports
from keras.models import Sequential
from sklearn.model_selection import train_test_split
from keras.layers import Dense, Dropout, Activation
from keras.initializers import RandomNormal, VarianceScaling, RandomUniform
from keras.optimizers import SGD, Adam, Nadam, RMSprop
# System imports
import sys
import os
import numpy as np
os.environ['TF_CPP_MIN_LOG_LEVEL'] = '2'
def train_model(X, y, num_streams, num_stages):
'''
STEP1: Initialize the Model
'''
tr_X, ts_X, tr_y, ts_y = train_test_split(X, y, train_size=.8)
model = initialize_model(num_streams, num_stages)
'''
STEP2: Train the Model
'''
model.compile(loss='binary_crossentropy',
optimizer=Adam(lr=1e-3),
metrics=['accuracy'])
model.fit(tr_X, tr_y,
validation_data=(ts_X, ts_y),
epochs=3,
batch_size=200)
def initialize_model(num_streams, num_stages):
model = Sequential()
hidden_units = 2 ** (num_streams + 1)
# init = VarianceScaling(scale=5.0, mode='fan_in', distribution='normal')
init_bound1 = np.sqrt(3.5/((num_stages + 1) + num_stages))
init_bound2 = np.sqrt(3.5/((num_stages + 1) + hidden_units))
init_bound3 = np.sqrt(3.5/(hidden_units + 1))
# drop_out = np.random.uniform(0, 1, 3)
# This is the input layer (that's why you have to state input_dim value)
model.add(Dense(num_stages,
input_dim=num_stages,
activation='relu',
kernel_initializer=RandomUniform(minval=-init_bound1, maxval=init_bound1)))
model.add(Dense(hidden_units,
activation='relu',
kernel_initializer=RandomUniform(minval=-init_bound2, maxval=init_bound2)))
# model.add(Dropout(drop_out[1]))
# This is the output layer
model.add(Dense(1,
activation='sigmoid',
kernel_initializer=RandomUniform(minval=-init_bound3, maxval=init_bound3)))
return model
的問題是,我得到99%的準確度與相同的數據集X
和y
當使用MLPClassifier sklearn
。但是,Keras給出的準確度差,如下所示:
Train on 100000 samples, validate on 25000 samples
Epoch 1/3
100000/100000 [==============================] - 1s - loss: -0.5358 - acc: 0.0022 - val_loss: -0.7322 - val_acc: 0.0000e+00
Epoch 2/3
100000/100000 [==============================] - 1s - loss: -0.6353 - acc: 0.0000e+00 - val_loss: -0.7385 - val_acc: 0.0000e+00
Epoch 3/3
100000/100000 [==============================] - 1s - loss: -0.7720 - acc: 9.0000e-05 - val_loss: -0.9474 - val_acc: 5.2000e-04
我不明白爲什麼?我在這裏錯過了什麼嗎?任何幫助表示讚賞。
是不是覺得,這是一個二元分類問題 –