我有一个数据框架->数据与形状(10000,257)。我需要对此数据进行预处理,以便能够在LSTM中使用它,LSTM需要一个三维输入-(nrow、which步骤、ntimesteps ),我正在使用这里提供的代码片段:
def univariate_processing(variable, window):
import numpy as np
# create empty 2D matrix from variable
V = np.empty((len(variable)-window+1, window))
# take each row/time window
for i in range(V.shape[0]):
V[i,:] = variable[i : i+window]
V = V.astype(np.float32) # set common data type
return V
def RNN_regprep(df, y, len_input, len_pred): #, test_size):
# create 3D matrix for multivariate input
X = np.empty((df.shape[0]-len_input+1, len_input, df.shape[1]))
# Iterate univariate preprocessing on all variables - store them in XM
for i in range(df.shape[1]):
X[ : , : , i ] = univariate_processing(df[:,i], len_input)
# create 2D matrix of y sequences
y = y.reshape((-1,)) # reshape to 1D if needed
Y = univariate_processing(y, len_pred)
## Trim dataframes as explained
X = X[ :-(len_pred + 1) , : , : ]
Y = Y[len_input:-1 , :]
# Set common datatype
X = X.astype(np.float32)
Y = Y.astype(np.float32)
return X, Y
X,y = RNN_regprep(data,label, len_ipnut=200,len_pred=1)
在运行此操作时,将获得以下错误:
numpy.core._exceptions._ArrayMemoryError: Unable to allocate 28.9 GiB for an array with shape (10000, 200, 257) and data type float64
我确实明白,这更多的是我在服务器内存中的问题。我想知道我可以在代码中修改的任何解决方案,看看是否可以避免这个内存错误或尝试减少这个内存消耗?
发布于 2022-05-02 06:05:56
这就是窗口视图的用途。使用我的食谱here
var = np.random.rand(10000,257)
w = window_nd(var, 200, axis = 0)
现在您在var
上有了一个窗口视图
w.shape
Out[]: (9801, 200, 257)
但是,重要的是,它使用了与var
完全相同的数据,只是以窗口的方式查看它:
w.__array_interface__['data'] #This is the memory's starting address
Out[]: (1448954720320, False)
var.__array_interface__['data']
Out[]: (1448954720320, False)
np.shares_memory(var, w)
Out[]: True
w.base.base.base is var #(lots of rearranging views in the background)
Out[]: True
所以你可以:
def univariate_processing(variable, window):
return window_nd(variable, window, axis = 0)
这将大大减少内存分配,不需要“魔术”:)
你也可以试试
from skimage.util import view_as_windows
w = np.squeeze(view_as_windows(var, (200, 1)))
它做的事情几乎一样。在这种情况下,你的回答是:
def univariate_processing(variable, window):
from skimage.util import view_as_windows
window = (window,) + (1,)*(len(variable.shape)-1)
return np.squeeze(view_as_windows(variable, window))
https://stackoverflow.com/questions/72082440
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