基于PaddlePaddle2.0.0rc使用LSTM进行北京空气污染序列预测

本项目基于PaddlePaddle2.0.0rc，用2010-2014年北京空气污染数据，通过LSTM和DNN对比预测未来一天某时刻PM2.5。经数据预处理、标准化和滑窗处理，构建模型训练。结果显示，LSTM在时序预测上效果更优，验证集MAE损失更低，未出现过拟合，更适合此类任务。

项目介绍：基于PaddlePaddle2.0.0rc使用LSTM进行北京空气污染序列预测

使用长短期记忆网络LSTM来预测未来的北京的空气污染情况，数据集使用的是北京2010.1.1至2014.12.31之间的空气污染数据，数据采用结构化表格的形式，包括year,month,day,hour等时间信息，以及对应的pm2.5,DEWP,TEMP,PRES,cbwd,Iws,Is,Ir等指标，任务是通过给定的数据来预测未来一天某个时刻空气指标PM2.5的数值，本项目是采用七天的滑窗数据预测后一天第24小时的pm2.5数值。首先是搭建了DNN网络作为对比，再尝试了LSTM网络。对比两者的预测结果maeloss曲线，得出结论：对应本项目这样的时序预测任务，使用LSTM具有更好的效果

创建时间：2020年10月12日15:34:47

注意事项

安装PaddlePaddle2.0 develop

# !python  -m pip install paddlepaddle-gpu==2.0.0rc0.post101 -f https://paddlepaddle.org.cn/whl/stable.html

导入必要的包

import paddleimport paddle.fluid as fluidimport paddle.fluid.layers as layersimport pandas as pdimport numpy as npimport matplotlib.pyplot as plt%matplotlib inline

/opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/pandas/core/tools/datetimes.py:3: DeprecationWarning: Using or importing the ABCs from 'collections' instead of from 'collections.abc' is deprecated, and in 3.8 it will stop working  from collections import MutableMapping/opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/matplotlib/rcsetup.py:20: DeprecationWarning: Using or importing the ABCs from 'collections' instead of from 'collections.abc' is deprecated, and in 3.8 it will stop working  from collections import Iterable, Mapping/opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/matplotlib/colors.py:53: DeprecationWarning: Using or importing the ABCs from 'collections' instead of from 'collections.abc' is deprecated, and in 3.8 it will stop working  from collections import Sized

特征工程

读取数据集并查看

data = pd.read_csv('data/data55547/PRSA_data_2010.1.1-2014.12.31.csv')#查看数据大小，类型及是否存在缺失值data.info()

RangeIndex: 43824 entries, 0 to 43823Data columns (total 13 columns):No       43824 non-null int64year     43824 non-null int64month    43824 non-null int64day      43824 non-null int64hour     43824 non-null int64pm2.5    41757 non-null float64DEWP     43824 non-null int64TEMP     43824 non-null float64PRES     43824 non-null float64cbwd     43824 non-null objectIws      43824 non-null float64Is       43824 non-null int64Ir       43824 non-null int64dtypes: float64(4), int64(8), object(1)memory usage: 4.3+ MB

从上面的信息中可知pm2.5项目存在缺失值（non-null数量为41757少于其他项目43824 ），查看缺失数据

data[data['pm2.5'].isna()]

          No  year  month  day  hour  pm2.5  DEWP  TEMP    PRES cbwd     Iws  \0          1  2010      1    1     0    NaN   -21 -11.0  1021.0   NW    1.79   1          2  2010      1    1     1    NaN   -21 -12.0  1020.0   NW    4.92   2          3  2010      1    1     2    NaN   -21 -11.0  1019.0   NW    6.71   3          4  2010      1    1     3    NaN   -21 -14.0  1019.0   NW    9.84   4          5  2010      1    1     4    NaN   -20 -12.0  1018.0   NW   12.97   5          6  2010      1    1     5    NaN   -19 -10.0  1017.0   NW   16.10   6          7  2010      1    1     6    NaN   -19  -9.0  1017.0   NW   19.23   7          8  2010      1    1     7    NaN   -19  -9.0  1017.0   NW   21.02   8          9  2010      1    1     8    NaN   -19  -9.0  1017.0   NW   24.15   9         10  2010      1    1     9    NaN   -20  -8.0  1017.0   NW   27.28   10        11  2010      1    1    10    NaN   -19  -7.0  1017.0   NW   31.30   11        12  2010      1    1    11    NaN   -18  -5.0  1017.0   NW   34.43   12        13  2010      1    1    12    NaN   -19  -5.0  1015.0   NW   37.56   13        14  2010      1    1    13    NaN   -18  -3.0  1015.0   NW   40.69   14        15  2010      1    1    14    NaN   -18  -2.0  1014.0   NW   43.82   15        16  2010      1    1    15    NaN   -18  -1.0  1014.0   cv    0.89   16        17  2010      1    1    16    NaN   -19  -2.0  1015.0   NW    1.79   17        18  2010      1    1    17    NaN   -18  -3.0  1015.0   NW    2.68   18        19  2010      1    1    18    NaN   -18  -5.0  1016.0   NE    1.79   19        20  2010      1    1    19    NaN   -17  -4.0  1017.0   NW    1.79   20        21  2010      1    1    20    NaN   -17  -5.0  1017.0   cv    0.89   21        22  2010      1    1    21    NaN   -17  -5.0  1018.0   NW    1.79   22        23  2010      1    1    22    NaN   -17  -5.0  1018.0   NW    2.68   23        24  2010      1    1    23    NaN   -17  -5.0  1020.0   cv    0.89   545      546  2010      1   23    17    NaN   -18   2.0  1024.0   NW   91.22   546      547  2010      1   23    18    NaN   -18   1.0  1024.0   NW   96.14   547      548  2010      1   23    19    NaN   -17   0.0  1024.0   NW  100.16   548      549  2010      1   23    20    NaN   -18   0.0  1024.0   SE    1.79   549      550  2010      1   23    21    NaN   -15  -3.0  1024.0   cv    0.89   550      551  2010      1   23    22    NaN   -16   0.0  1023.0   NW    1.79   ...      ...   ...    ...  ...   ...    ...   ...   ...     ...  ...     ...   42847  42848  2014     11   21     7    NaN    -3   0.0  1020.0   NW   11.17   42848  42849  2014     11   21     8    NaN    -3   0.0  1020.0   cv    0.89   43190  43191  2014     12    5    14    NaN   -22   4.0  1025.0   NW   41.12   43191  43192  2014     12    5    15    NaN   -22   3.0  1025.0   NE    1.79   43264  43265  2014     12    8    16    NaN   -13   3.0  1033.0   cv    1.79   43266  43267  2014     12    8    18    NaN   -11  -2.0  1034.0   SE    0.89   43267  43268  2014     12    8    19    NaN   -11  -2.0  1035.0   SE    1.78   43268  43269  2014     12    8    20    NaN   -11  -4.0  1036.0   SE    2.67   43269  43270  2014     12    8    21    NaN   -11  -5.0  1036.0   SE    3.56   43270  43271  2014     12    8    22    NaN   -11  -5.0  1036.0   NE    0.89   43273  43274  2014     12    9     1    NaN   -11  -4.0  1037.0   cv    0.89   43274  43275  2014     12    9     2    NaN   -10  -5.0  1036.0   SE    0.89   43275  43276  2014     12    9     3    NaN   -10  -6.0  1037.0   cv    0.89   43276  43277  2014     12    9     4    NaN   -10  -7.0  1036.0   cv    1.78   43277  43278  2014     12    9     5    NaN   -11  -6.0  1036.0   cv    2.67   43278  43279  2014     12    9     6    NaN   -11  -7.0  1036.0   cv    3.56   43279  43280  2014     12    9     7    NaN   -11  -8.0  1036.0   cv    4.45   43280  43281  2014     12    9     8    NaN    -9  -6.0  1036.0   SE    0.89   43281  43282  2014     12    9     9    NaN    -8  -5.0  1037.0   NE    1.79   43282  43283  2014     12    9    10    NaN    -8  -4.0  1037.0   cv    0.89   43283  43284  2014     12    9    11    NaN    -8  -3.0  1036.0   NE    1.79   43544  43545  2014     12   20     8    NaN   -18  -4.0  1031.0   NW  225.30   43545  43546  2014     12   20     9    NaN   -17  -4.0  1031.0   NW  228.43   43546  43547  2014     12   20    10    NaN   -18  -2.0  1031.0   NW  233.35   43547  43548  2014     12   20    11    NaN   -17  -1.0  1031.0   NW  239.16   43548  43549  2014     12   20    12    NaN   -18   0.0  1030.0   NW  244.97   43549  43550  2014     12   20    13    NaN   -19   1.0  1029.0   NW  249.89   43550  43551  2014     12   20    14    NaN   -20   1.0  1029.0   NW  257.04   43551  43552  2014     12   20    15    NaN   -20   2.0  1028.0   NW  262.85   43552  43553  2014     12   20    16    NaN   -21   1.0  1028.0   NW  270.00          Is  Ir  0       0   0  1       0   0  2       0   0  3       0   0  4       0   0  5       0   0  6       0   0  7       0   0  8       0   0  9       0   0  10      0   0  11      0   0  12      0   0  13      0   0  14      0   0  15      0   0  16      0   0  17      0   0  18      0   0  19      0   0  20      0   0  21      0   0  22      0   0  23      0   0  545     0   0  546     0   0  547     0   0  548     0   0  549     0   0  550     0   0  ...    ..  ..  42847   0   0  42848   0   0  43190   0   0  43191   0   0  43264   0   0  43266   0   0  43267   0   0  43268   0   0  43269   0   0  43270   0   0  43273   0   0  43274   0   0  43275   0   0  43276   0   0  43277   0   0  43278   0   0  43279   0   0  43280   0   0  43281   0   0  43282   0   0  43283   0   0  43544   0   0  43545   0   0  43546   0   0  43547   0   0  43548   0   0  43549   0   0  43550   0   0  43551   0   0  43552   0   0  [2067 rows x 13 columns]

对缺失数据进行填充

我们采用'ffill'的填充方法,由于0-24之间为nan且0-24前面无数据，无法实现填充，因此去除这段数据

查看数据，获得完整无缺失值的数据

data = data.iloc[24:].copy()#由于0-24之间为nan,我们采用'ffill'的填充方法,由于0-24前面无数据，无法实现填充data.fillna(method='ffill', inplace=True)data.info()

RangeIndex: 43800 entries, 24 to 43823Data columns (total 13 columns):No       43800 non-null int64year     43800 non-null int64month    43800 non-null int64day      43800 non-null int64hour     43800 non-null int64pm2.5    43800 non-null float64DEWP     43800 non-null int64TEMP     43800 non-null float64PRES     43800 non-null float64cbwd     43800 non-null objectIws      43800 non-null float64Is       43800 non-null int64Ir       43800 non-null int64dtypes: float64(4), int64(8), object(1)memory usage: 4.3+ MB

去除索引值，将索引值替换为时间，查看数据

data.drop('No', axis=1, inplace=True)

import datetimedata['time'] = data.apply(lambda x: datetime.datetime(year=x['year'],                                       month=x['month'],                                       day=x['day'],                                        hour=x['hour']),                           axis=1)

data.set_index('time', inplace=True)data.drop(columns=['year', 'month', 'day', 'hour'], inplace=True)data.head()

                     pm2.5  DEWP  TEMP    PRES cbwd   Iws  Is  Irtime                                                             2010-01-02 00:00:00  129.0   -16  -4.0  1020.0   SE  1.79   0   02010-01-02 01:00:00  148.0   -15  -4.0  1020.0   SE  2.68   0   02010-01-02 02:00:00  159.0   -11  -5.0  1021.0   SE  3.57   0   02010-01-02 03:00:00  181.0    -7  -5.0  1022.0   SE  5.36   1   02010-01-02 04:00:00  138.0    -7  -5.0  1022.0   SE  6.25   2   0

为了方便理解数据含义，替换表头

data.columns = ['pm2.5', 'dew', 'temp', 'press', 'cbwd', 'iws', 'snow', 'rain']

查看cbwd项目下的数据，其数据只有四种不同的值，对整体的预测任务影响不大，去除该项目

data.cbwd.unique()

array(['SE', 'cv', 'NW', 'NE'], dtype=object)

del data['cbwd']

data.info()

DatetimeIndex: 43800 entries, 2010-01-02 00:00:00 to 2014-12-31 23:00:00Data columns (total 7 columns):pm2.5    43800 non-null float64dew      43800 non-null int64temp     43800 non-null float64press    43800 non-null float64iws      43800 non-null float64snow     43800 non-null int64rain     43800 non-null int64dtypes: float64(4), int64(3)memory usage: 2.7 MB

绘图查看数据

data['pm2.5'][-1000:].plot()

/opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/matplotlib/cbook/__init__.py:2349: DeprecationWarning: Using or importing the ABCs from 'collections' instead of from 'collections.abc' is deprecated, and in 3.8 it will stop working  if isinstance(obj, collections.Iterator):/opt/conda/envs/python35-paddle120-env/lib/python3.7/site-packages/matplotlib/cbook/__init__.py:2366: DeprecationWarning: Using or importing the ABCs from 'collections' instead of from 'collections.abc' is deprecated, and in 3.8 it will stop working  return list(data) if isinstance(data, collections.MappingView) else data

data['temp'][-1000:].plot()

#查看数据data.head(3)

                     pm2.5  dew  temp   press   iws  snow  raintime                                                           2010-01-02 00:00:00  129.0  -16  -4.0  1020.0  1.79     0     02010-01-02 01:00:00  148.0  -15  -4.0  1020.0  2.68     0     02010-01-02 02:00:00  159.0  -11  -5.0  1021.0  3.57     0     0

数据标准化，要注意数据标准化应该在训练数据集上，以训练数据的均值和方差作为整个数据的均值和方差

思考：为什么label不需要标准化呢？ 从标准化的目的的角度来看，标准化是为了使得不同特征的数据规范到一个统一的范围，有利于神经网络的反向传播（假如不进行规范化，神经网络可能会刻意捕捉不同批次数据的变化，而忽视了预测任务本身），label也可以做标准化，但是预测时还得反向推导出需要的结果。

建立时间滑窗，我们使用前5天（每天24小时）来预测后一天（24小时中某个时间点的数据，这里预测第24时）

sequence_length = 5*24delay = 24# Generated training sequences for use in the model.def create_sequences(values, time_steps=sequence_length+delay):    output = []    for i in range(len(values) - time_steps):        output.append(values[i : (i + time_steps)])    return np.stack(output)data_ = create_sequences(data.values)print("Training input shape: ", data_.shape)

Training input shape:  (43656, 144, 7)

划分数据集，80%为训练集，20%为测试集，查看数据集形状,使用前120个小时的数据预测接下来24个小时中某个时刻的pm2.5的值

对数据集进行标准化

split_boundary = int(data_.shape[0] * 0.8)train = data_[: split_boundary]test = data_[split_boundary:]mean = train.mean(axis=0)std = train.std(axis=0)train = (train - mean)/stdtest = (test - mean)/stdtrain.shape,test.shape

((34924, 144, 7), (8732, 144, 7))

#数据生成器def switch_reader(is_val: bool = False):    def reader():        # 判断是否是验证集        if is_val:            # 抽取数据使用迭代器返回            for te in test:                yield te[:sequence_length],te[-1:][:,0]        else:            # 抽取数据使用迭代器返回            for tr in train:                yield tr[:sequence_length],tr[-1:][:,0]#只取第0列pm2.5的值为label            return reader   # 注意！此处不需要带括号# 划分batchbatch_size = 128train_reader = fluid.io.batch(reader=switch_reader(), batch_size=batch_size)val_reader = fluid.io.batch(reader=switch_reader(is_val=True), batch_size=batch_size)for data in train_reader():    # print(data[0].shape,data[1].shape)    train_x=np.array([x[0] for x in data],np.float32)    train_y = np.array([x[1] for x in data]).astype('int64')    print(train_x.shape,train_y.shape)

建立模型DNN

拿到一个任务，首先从简单的模型试起，这里首先选择最简单的两层神经网络，网络可以自己随意添加层数，可以自己尝试调整各种超参数

#定义DNN网络class MyModel(fluid.dygraph.Layer):    '''    DNN网络    '''    def __init__(self):        super(MyModel,self).__init__()        self.fc1=fluid.dygraph.Linear(5*24*7,32,act='relu')        self.fc2=fluid.dygraph.Linear(32,1)            def forward(self,input):        # forward 定义执行实际运行时网络的执行逻辑        '''前向计算'''        # print('input',input.shape)        input =fluid.layers.reshape(input,shape=[-1,5*24*7])        out=self.fc1(input)        out=self.fc2(out)        # print(out.shape)        return out

定义绘图函数

Batch=0Batchs=[]all_train_loss=[]def draw_train_loss(Batchs, train_loss,eval_loss):    title="training-eval loss"    plt.title(title, fontsize=24)    plt.xlabel("batch", fontsize=14)    plt.ylabel("loss", fontsize=14)    plt.plot(Batchs, train_loss, color='red', label='training loss')    plt.plot(Batchs, eval_loss, color='g', label='eval loss')    plt.legend()    plt.grid()    plt.show()

启动训练

# place = fluid.CUDAPlace(0) #非develop版本请勿使用GPU版本place = fluid.CPUPlace() with fluid.dygraph.guard(place):    model=MyModel() #模型实例化    model.train() #训练模式    # opt=fluid.optimizer.SGDOptimizer(learning_rate=train_parameters['learning_strategy']['lr'], parameter_list=model.parameters())#优化器选用SGD随机梯度下降，学习率为0.001.    opt=fluid.optimizer.AdamOptimizer(learning_rate=0.0001, parameter_list=model.parameters())     epochs_num=100#迭代次数    batch_size = 128*16    train_reader = fluid.io.batch(reader=switch_reader(), batch_size=batch_size)    val_reader = fluid.io.batch(reader=switch_reader(is_val=True), batch_size=batch_size)    Batch=0    Batchs=[]    all_train_loss=[]    all_eval_loss=[]    for pass_num in range(epochs_num):        for batch_id, data in enumerate(train_reader()):             data_x=np.array([x[0] for x in data],np.float32)            data_y = np.array([x[1] for x in data]).astype('float32')            data_x = fluid.dygraph.to_variable(data_x)            data_y = fluid.dygraph.to_variable(data_y)                    # print(data_x.shape, data_y.shape)            predict=model(data_x)            # print(predict.shape)            loss=fluid.layers.mse_loss(predict,data_y)            avg_loss=fluid.layers.mean(loss)#获取loss值            avg_loss.backward()                   opt.minimize(avg_loss)    #优化器对象的minimize方法对参数进行更新             model.clear_gradients()   #model.clear_gradients()来重置梯度            if batch_id!=0 and batch_id%10==0:                Batch = Batch+10                 Batchs.append(Batch)                all_train_loss.append(avg_loss.numpy()[0])                evalavg_loss=[]                for eval_data in val_reader():                    eval_data_x = np.array([x[0] for x in eval_data],np.float32)                    eval_data_y = np.array([x[1] for x in eval_data]).astype('float32')                    eval_data_x = fluid.dygraph.to_variable(eval_data_x)                    eval_data_y = fluid.dygraph.to_variable(eval_data_y)                    eval_predict=model(eval_data_x)                    eval_loss=fluid.layers.mse_loss(eval_predict,eval_data_y)                    eval_loss=fluid.layers.mean(eval_loss)                    evalavg_loss.append(eval_loss.numpy()[0])#获取loss值                all_eval_loss.append(sum(evalavg_loss)/len(evalavg_loss))        print("epoch:{},batch_id:{},train_loss:{},eval_loss:{}".format(pass_num,batch_id,avg_loss.numpy(),sum(evalavg_loss)/len(evalavg_loss)))         fluid.save_dygraph(model.state_dict(),'MyModel')#保存模型    fluid.save_dygraph(opt.state_dict(),'MyModel')#保存模型    print("Final loss: {}".format(avg_loss.numpy()))    #让我们绘制训练图和验证损失图，以了解训练的进行情况。     draw_train_loss(Batchs,all_train_loss,all_eval_loss)

epoch:0,batch_id:17,train_loss:[2.0205],eval_loss:1.4090836882591247epoch:1,batch_id:17,train_loss:[0.95689076],eval_loss:1.3361332535743713epoch:2,batch_id:17,train_loss:[0.7040673],eval_loss:1.2218480825424194epoch:3,batch_id:17,train_loss:[0.55722934],eval_loss:1.1956807255744935epoch:4,batch_id:17,train_loss:[0.44944313],eval_loss:1.1633899331092834epoch:5,batch_id:17,train_loss:[0.37596697],eval_loss:1.1420036435127259epoch:6,batch_id:17,train_loss:[0.31873935],eval_loss:1.1268895626068116epoch:7,batch_id:17,train_loss:[0.27411735],eval_loss:1.1125162959098815epoch:8,batch_id:17,train_loss:[0.2403403],eval_loss:1.1013256669044496epoch:9,batch_id:17,train_loss:[0.21393616],eval_loss:1.0918826699256896epoch:10,batch_id:17,train_loss:[0.19293499],eval_loss:1.0833844304084779epoch:11,batch_id:17,train_loss:[0.17653875],eval_loss:1.076257163286209epoch:12,batch_id:17,train_loss:[0.16238903],eval_loss:1.0695580899715424epoch:13,batch_id:17,train_loss:[0.15100743],eval_loss:1.0639597535133363epoch:14,batch_id:17,train_loss:[0.14186515],eval_loss:1.0592819035053254epoch:15,batch_id:17,train_loss:[0.13479522],eval_loss:1.055191159248352epoch:16,batch_id:17,train_loss:[0.1290898],eval_loss:1.051255214214325epoch:17,batch_id:17,train_loss:[0.12424426],eval_loss:1.047574871778488epoch:18,batch_id:17,train_loss:[0.11999645],eval_loss:1.0441474676132203epoch:19,batch_id:17,train_loss:[0.11639561],eval_loss:1.0410736680030823epoch:20,batch_id:17,train_loss:[0.11316744],eval_loss:1.038214284181595epoch:21,batch_id:17,train_loss:[0.11018123],eval_loss:1.0353180170059204epoch:22,batch_id:17,train_loss:[0.10779685],eval_loss:1.032786226272583epoch:23,batch_id:17,train_loss:[0.10557291],eval_loss:1.0302606165409087epoch:24,batch_id:17,train_loss:[0.1037445],eval_loss:1.0279349327087401epoch:25,batch_id:17,train_loss:[0.10192361],eval_loss:1.025689673423767epoch:26,batch_id:17,train_loss:[0.10021695],eval_loss:1.023529589176178epoch:27,batch_id:17,train_loss:[0.0984721],eval_loss:1.0216342866420747epoch:28,batch_id:17,train_loss:[0.09707484],eval_loss:1.019782018661499epoch:29,batch_id:17,train_loss:[0.0957087],eval_loss:1.0179351627826692epoch:30,batch_id:17,train_loss:[0.09425645],eval_loss:1.0161666870117188epoch:31,batch_id:17,train_loss:[0.09265903],eval_loss:1.0144980549812317epoch:32,batch_id:17,train_loss:[0.09125529],eval_loss:1.0129337430000305epoch:33,batch_id:17,train_loss:[0.08980759],eval_loss:1.0113472878932952epoch:34,batch_id:17,train_loss:[0.08829899],eval_loss:1.0098000168800354epoch:35,batch_id:17,train_loss:[0.08709818],eval_loss:1.0085288822650909epoch:36,batch_id:17,train_loss:[0.08586626],eval_loss:1.0073016047477723epoch:37,batch_id:17,train_loss:[0.08476242],eval_loss:1.0060584604740144epoch:38,batch_id:17,train_loss:[0.08362537],eval_loss:1.0050600707530974epoch:39,batch_id:17,train_loss:[0.08273471],eval_loss:1.0040717482566834epoch:40,batch_id:17,train_loss:[0.08195919],eval_loss:1.0030322968959808epoch:41,batch_id:17,train_loss:[0.0810699],eval_loss:1.0020980298519135epoch:42,batch_id:17,train_loss:[0.07989511],eval_loss:1.0009490311145783epoch:43,batch_id:17,train_loss:[0.07878471],eval_loss:0.9999779641628266epoch:44,batch_id:17,train_loss:[0.07754707],eval_loss:0.9990507960319519epoch:45,batch_id:17,train_loss:[0.07625636],eval_loss:0.997998195886612epoch:46,batch_id:17,train_loss:[0.07513986],eval_loss:0.9971686065196991epoch:47,batch_id:17,train_loss:[0.07390005],eval_loss:0.9962048828601837epoch:48,batch_id:17,train_loss:[0.07286156],eval_loss:0.9953225016593933epoch:49,batch_id:17,train_loss:[0.07175022],eval_loss:0.9946246147155762epoch:50,batch_id:17,train_loss:[0.07077469],eval_loss:0.993957793712616epoch:51,batch_id:17,train_loss:[0.06977923],eval_loss:0.993251645565033epoch:52,batch_id:17,train_loss:[0.06907593],eval_loss:0.992446219921112epoch:53,batch_id:17,train_loss:[0.06824756],eval_loss:0.991847711801529epoch:54,batch_id:17,train_loss:[0.06763344],eval_loss:0.9912112653255463epoch:55,batch_id:17,train_loss:[0.06695005],eval_loss:0.9905830025672913epoch:56,batch_id:17,train_loss:[0.06627547],eval_loss:0.9900696039199829epoch:57,batch_id:17,train_loss:[0.06573104],eval_loss:0.9896724104881287epoch:58,batch_id:17,train_loss:[0.06506079],eval_loss:0.9892310202421735epoch:59,batch_id:17,train_loss:[0.06436179],eval_loss:0.9887569844722748epoch:60,batch_id:17,train_loss:[0.06374478],eval_loss:0.9883864879608154epoch:61,batch_id:17,train_loss:[0.06303963],eval_loss:0.9881407439708709epoch:62,batch_id:17,train_loss:[0.06245909],eval_loss:0.9878709852695465epoch:63,batch_id:17,train_loss:[0.06174919],eval_loss:0.9875110030174256epoch:64,batch_id:17,train_loss:[0.06118464],eval_loss:0.987206107378006epoch:65,batch_id:17,train_loss:[0.06051154],eval_loss:0.9869666278362275epoch:66,batch_id:17,train_loss:[0.05986768],eval_loss:0.9865923523902893epoch:67,batch_id:17,train_loss:[0.05928758],eval_loss:0.9863128185272216epoch:68,batch_id:17,train_loss:[0.05866254],eval_loss:0.985930305719375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loss: [0.04528417]

使用LSTM进行预测

长短期记忆网络飞桨API：

该OP是长短期记忆网络（LSTM），根据输出序列和给定的初始状态计算返回输出序列和最终状态。在该网络中的每一层对应输入的step，每个step根据当前时刻输入 xt 和上一时刻状态 ht−1,ct−1 计算当前时刻输出 yt 并更新状态 ht,ct 。

状态更新公式如下：
       

输入 :

inputs (Tensor) - 网络输入。如果time_major为True，则Tensor的形状为[time_steps,batch_size,input_size]，如果time_major为False，则Tensor的形状为[batch_size,time_steps,input_size]。

initial_states (tuple，可选) - 网络的初始状态，一个包含h和c的元组，形状为[num_lauers * num_directions, batch_size, hidden_size]。如果没有给出则会以全零初始化。

sequence_length (Tensor，可选) - 指定输入序列的长度，形状为[batch_size]，数据类型为int64或int32。在输入序列中所有time step不小于sequence_length的元素都会被当作填充元素处理（状态不再更新）。

输出:

outputs (Tensor) - 输出，由前向和后向cell的输出拼接得到。如果time_major为True，则Tensor的形状为[time_steps,batch_size,num_directions * hidden_size]，如果time_major为False，则Tensor的形状为[batch_size,time_steps,num_directions * hidden_size]，当direction设置为bidirectional时，num_directions等于2，否则等于1。

final_states (tuple) - 最终状态,一个包含h和c的元组。形状为[num_lauers * num_directions, batch_size, hidden_size],当direction设置为bidirectional时，num_directions等于2，否则等于1。

#定义LSTM网络import paddle.fluid as fluidclass MyLSTMModel(fluid.dygraph.Layer):    '''    DNN网络    '''    def __init__(self):        super(MyLSTMModel,self).__init__()        self.rnn = paddle.nn.LSTM(7, 14, 2)        self.flatten = paddle.nn.Flatten()        self.fc1=fluid.dygraph.Linear(120*14,120)        self.fc2=fluid.dygraph.Linear(120,1)            def forward(self,input):        # forward 定义执行实际运行时网络的执行逻辑        '''前向计算'''        # print('input',input.shape)        out, (h, c)=self.rnn(input)        out =self.flatten(out)        out=self.fc1(out)        out=self.fc2(out)        return out

启动训练

Batch=0Batchs=[]all_train_loss=[]def draw_train_loss(Batchs, train_loss,eval_loss):    title="training-eval loss"    plt.title(title, fontsize=24)    plt.xlabel("batch", fontsize=14)    plt.ylabel("loss", fontsize=14)    plt.plot(Batchs, train_loss, color='red', label='training loss')    plt.plot(Batchs, eval_loss, color='g', label='eval loss')    plt.legend()    plt.grid()    plt.show()

import paddle# place = fluid.CUDAPlace(0) #非develop版本请勿使用GPU版本place = fluid.CPUPlace()with fluid.dygraph.guard(place):    model=MyLSTMModel() #模型实例化    # model=MyModel()    model.train() #训练模式    # opt=fluid.optimizer.SGDOptimizer(learning_rate=0.001, parameter_list=model.parameters())#优化器选用SGD随机梯度下降，学习率为0.001.    opt=fluid.optimizer.AdamOptimizer(learning_rate=0.01, parameter_list=model.parameters())     epochs_num=100#迭代次数    batch_size = 128*32    train_reader = fluid.io.batch(reader=switch_reader(), batch_size=batch_size)    val_reader = fluid.io.batch(reader=switch_reader(is_val=True), batch_size=batch_size)    Batch=0    Batchs=[]    all_train_loss=[]    all_eval_loss=[]    for pass_num in range(epochs_num):        for batch_id, data in enumerate(train_reader()):             data_x=np.array([x[0] for x in data],np.float32)            data_y = np.array([x[1] for x in data]).astype('float32')            data_x = fluid.dygraph.to_variable(data_x)            data_y = fluid.dygraph.to_variable(data_y)                    # print(data_x.shape, data_y.shape)            predict=model(data_x)            # print(predict.shape)            loss=fluid.layers.mse_loss(predict,data_y)            avg_loss=fluid.layers.mean(loss)#获取loss值            avg_loss.backward()                   opt.minimize(avg_loss)    #优化器对象的minimize方法对参数进行更新             model.clear_gradients()   #model.clear_gradients()来重置梯度            if batch_id!=0 and batch_id%1==0:                Batch = Batch+1                 Batchs.append(Batch)                all_train_loss.append(avg_loss.numpy()[0])                evalavg_loss=[]                for eval_data in val_reader():                    eval_data_x = np.array([x[0] for x in eval_data],np.float32)                    eval_data_y = np.array([x[1] for x in eval_data]).astype('float32')                    eval_data_x = fluid.dygraph.to_variable(eval_data_x)                    eval_data_y = fluid.dygraph.to_variable(eval_data_y)                    eval_predict=model(eval_data_x)                    eval_loss=fluid.layers.mse_loss(eval_predict,eval_data_y)                    eval_loss=fluid.layers.mean(eval_loss)                    evalavg_loss.append(eval_loss.numpy()[0])#获取loss值                all_eval_loss.append(sum(evalavg_loss)/len(evalavg_loss))        print("epoch:{},batch_id:{},train_loss:{},eval_loss:{}".format(pass_num,batch_id,avg_loss.numpy(),sum(evalavg_loss)/len(evalavg_loss)))         fluid.save_dygraph(model.state_dict(),'MyLSTMModel')#保存模型    fluid.save_dygraph(opt.state_dict(),'MyLSTMModel')#保存模型    print("Final loss: {}".format(avg_loss.numpy()))    #让我们绘制训练图和验证损失图，以了解训练的进行情况。     draw_train_loss(Batchs,all_train_loss,all_eval_loss)

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loss: [0.9590464]

模型预测

import paddle# place = fluid.CUDAPlace(0) #非develop版本请勿使用GPU版本place = fluid.CPUPlace()with fluid.dygraph.guard(place):    accs = []    # model_dict, _ = fluid.load_dygraph('MyLSTMModel.pdopt')    model_dict, _ = fluid.load_dygraph('MyModel.pdopt')    model = MyModel()    # model=MyLSTMModel()    model.load_dict(model_dict) #加载模型参数    val_reader = fluid.io.batch(reader=switch_reader(is_val=True), batch_size=batch_size)    res=[]    for batch_id, eval_data in enumerate(val_reader()):        eval_data_x = np.array([x[0] for x in eval_data],np.float32)        eval_data_y = np.array([x[1] for x in eval_data]).astype('float32')        eval_data_x = fluid.dygraph.to_variable(eval_data_x)        eval_data_y = fluid.dygraph.to_variable(eval_data_y)        eval_predict=model(eval_data_x)        res.append(eval_predict)res

总结

你是一名 AI 行业编辑，请围绕下面这条热点输出一份资讯解读：
热点：基于PaddlePaddle2.0.0rc使用LSTM进行北京空气污染序列预测要求：
1. 先用一句话解释这条热点在讲什么
2. 再总结它为什么重要
3. 说明会影响哪些 AI 产品或内容方向
4. 最后给出 3 个适合资讯站使用的标题