数据集

太阳黑子数据集，Monthly Sunspots

下载

import numpy as np
import pandas as pd

url = "http://www.sidc.be/silso/INFO/snmtotcsv.php"
data = pd.read_csv (url,sep =";")
loc = "Monthly Sunspots.csv"
data . to_csv (loc , index = False )

data_csv = pd. read_csv (loc , header = None )
yt= data_csv . iloc [0:3210 ,3]
print(yt.head())
'''
0     96.7
1    104.3
2    116.7
3     92.8
4    141.7
Name: 3, dtype: float64
'''
print(yt.tail())
'''
3205    56.4
3206    54.1
3207    37.9
3208    51.5
3209    20.5
Name: 3, dtype: float64
'''
x_pacf=pacf(yt ,nlags=50, method='ols')
plt.plot(x_pacf)

该时间序列的 偏自相关函数【百度百科】

预处理

引入时滞

用紧邻的5个历史数据预测下一时刻

yt_1 =yt. shift (1)
yt_2 =yt. shift (2)
yt_3 =yt. shift (3)
yt_4 =yt. shift (4)
yt_5 =yt. shift (5)
data =pd. concat ([yt ,yt_1 , yt_2 ,yt_3 ,yt_4 ,yt_5 ], axis =1)
data . columns = ['yt', 'yt_1', 'yt_2', 'yt_3', 'yt_4', 'yt_5']
data = data . dropna ()  # 除去NULL，因为序列的起始点是没有历史的
print(data.tail( 6 ))
'''
        yt  yt_1  yt_2  yt_3  yt_4  yt_5
3204  57.0  58.0  62.2  63.6  78.6  64.4
3205  56.4  57.0  58.0  62.2  63.6  78.6
3206  54.1  56.4  57.0  58.0  62.2  63.6
3207  37.9  54.1  56.4  57.0  58.0  62.2
3208  51.5  37.9  54.1  56.4  57.0  58.0
3209  20.5  51.5  37.9  54.1  56.4  57.0
'''
print(data.head(6))
'''
       yt   yt_1   yt_2   yt_3   yt_4   yt_5
5   139.2  141.7   92.8  116.7  104.3   96.7
6   158.0  139.2  141.7   92.8  116.7  104.3
7   110.5  158.0  139.2  141.7   92.8  116.7
8   126.5  110.5  158.0  139.2  141.7   92.8
9   125.8  126.5  110.5  158.0  139.2  141.7
10  264.3  125.8  126.5  110.5  158.0  139.2
'''
y = data ['yt']
x = data ['yt_1', 'yt_2', 'yt_3', 'yt_4', 'yt_5']

归一化

scaler_x = preprocessing . MinMaxScaler (feature_range =(-1, 1))
x = np. array (x). reshape (( len(x) ,5 ))
x = scaler_x . fit_transform (x)
scaler_y = preprocessing . MinMaxScaler (
feature_range =( -1, 1))
y = np. array (y). reshape (( len(y), 1))
y = scaler_y . fit_transform (y)
train_end = 3042
x_train =x[0: train_end ,]
x_test =x[ train_end +1:3205 ,]
y_train =y[0: train_end ]
y_test =y[ train_end +1:3205]
x_train = x_train . reshape ( x_train . shape + (1 ,))
x_test = x_test . reshape ( x_test . shape + (1 ,))
print(x_train . shape)  # (3042, 5, 1)

LSTM

from keras . layers . recurrent import LSTM

seed =2019
np.random.seed( seed )

model = Sequential()
model .add(LSTM (units =4, activation = 'tanh', recurrent_activation ='hard_sigmoid',input_shape = (5 , 1)))
model .add(Dense (units =1, activation = 'linear'))
model . compile ( loss ='mean_squared_error',optimizer = 'rmsprop')
model .fit( x_train , y_train , batch_size =1, epochs =10 , shuffle = True ) ## shuffle matters！！ 
print(model . summary ())
'''
_________________________________________________________________
Layer (type)                 Output Shape              Param #   
=================================================================
lstm_16 (LSTM)               (None, 4)                 96        
_________________________________________________________________
dense_64 (Dense)             (None, 1)                 5         
=================================================================
Total params: 101
Trainable params: 101
Non-trainable params: 0
_________________________________________________________________
None
'''

score_train = model.evaluate (x_train , y_train , batch_size =1)
score_test = model.evaluate (x_test , y_test , batch_size =1)
print ("in train MSE = ", round( score_train,4))
print ("in test MSE = ", round( score_test ,4))

pred = model.predict(x_test)
# pred1 = scaler_y.inverse_transform(np.array(pred1).reshape((len(pred1), 1)))

plt.plot(y_test)
plt.plot(pred)
plt.legend(['target','prediction'])

训练时 shuffle

可以对比看看，不打乱数据集的训练效果会差一点。

打乱数据集：

不打乱数据集：

GRU

from keras . layers . recurrent import GRU

seed =2019
np. random . seed ( seed )
model = Sequential ()
model .add(GRU(units=4,
                return_sequences =False ,
                activation ='tanh', 
                recurrent_activation ='hard_sigmoid',
                input_shape =(5 , 1)))
model .add(Dense(units =1, activation ='linear'))
model . compile (loss ='mean_squared_error',optimizer ='rmsprop')
print(model . summary ())
'''
_________________________________________________________________
Layer (type)                 Output Shape              Param #   
=================================================================
gru_8 (GRU)                  (None, 4)                 72        
_________________________________________________________________
dense_23 (Dense)             (None, 1)                 5         
=================================================================
Total params: 77
Trainable params: 77
Non-trainable params: 0
_________________________________________________________________
None
'''
model .fit( x_train , y_train , batch_size =1,epochs =10)

score_train = model . evaluate ( x_train ,y_train , batch_size =1)
score_test = model . evaluate (x_test , y_test , batch_size =1)
print ("in train MSE = ", round( score_train,5))
print ("in test MSE = ", round( score_test ,5))

pred1 = model . predict ( x_test )
# pred1 = scaler_y .inverse_transform (np. array(pred1).reshape((len(pred1), 1)))

plt.plot(y_test)
plt.plot(pred1)
plt.legend(['target','prediction'])