Python 在numpy阵列上执行操作时获取内存错误
我正在对更高维的numpy数组执行一个包含不同操作(减法、平方、广播)的操作。我的代码在执行此类操作时出现Python 在numpy阵列上执行操作时获取内存错误,python,arrays,numpy,bigdata,Python,Arrays,Numpy,Bigdata,我正在对更高维的numpy数组执行一个包含不同操作(减法、平方、广播)的操作。我的代码在执行此类操作时出现内存错误 下面是我的代码- from skimage.segmentation import find_boundaries w0 = 10 sigma = 5 def make_weight_map(masks): """ Generate the weight maps as specified in the UNet paper for a set of b
内存错误
下面是我的代码-
from skimage.segmentation import find_boundaries
w0 = 10
sigma = 5
def make_weight_map(masks):
"""
Generate the weight maps as specified in the UNet paper
for a set of binary masks.
Parameters
----------
masks: array-like
A 3D array of shape (n_masks, image_height, image_width),
where each slice of the matrix along the 0th axis represents one binary mask.
Returns
-------
array-like
A 2D array of shape (image_height, image_width)
"""
masks = masks.numpy()
nrows, ncols = masks.shape[1:]
masks = (masks > 0).astype(int)
distMap = np.zeros((nrows * ncols, masks.shape[0]))
X1, Y1 = np.meshgrid(np.arange(nrows), np.arange(ncols))
X1, Y1 = np.c_[X1.ravel(), Y1.ravel()].T
#In the below for loop, I am getting the Memory Error
for i, mask in enumerate(masks):
# find the boundary of each mask,
# compute the distance of each pixel from this boundary
bounds = find_boundaries(mask, mode='inner')
X2, Y2 = np.nonzero(bounds)
xSum = (X2.reshape(-1, 1) - X1.reshape(1, -1)) ** 2
ySum = (Y2.reshape(-1, 1) - Y1.reshape(1, -1)) ** 2
distMap[:, i] = np.sqrt(xSum + ySum).min(axis=0)
ix = np.arange(distMap.shape[0])
if distMap.shape[1] == 1:
d1 = distMap.ravel()
border_loss_map = w0 * np.exp((-1 * (d1) ** 2) / (2 * (sigma ** 2)))
else:
if distMap.shape[1] == 2:
d1_ix, d2_ix = np.argpartition(distMap, 1, axis=1)[:, :2].T
else:
d1_ix, d2_ix = np.argpartition(distMap, 2, axis=1)[:, :2].T
d1 = distMap[ix, d1_ix]
d2 = distMap[ix, d2_ix]
border_loss_map = w0 * np.exp((-1 * (d1 + d2) ** 2) / (2 * (sigma ** 2)))
xBLoss = np.zeros((nrows, ncols))
xBLoss[X1, Y1] = border_loss_map
# class weight map
loss = np.zeros((nrows, ncols))
w_1 = 1 - masks.sum() / loss.size
w_0 = 1 - w_1
loss[masks.sum(0) == 1] = w_1
loss[masks.sum(0) == 0] = w_0
ZZ = xBLoss + loss
return ZZ
为了重现问题,维度的numpy数组4584565
可以重新创建问题
错误的回溯-
---------------------------------------------------------------------------
MemoryError Traceback (most recent call last)
<ipython-input-32-0f30ef7dc24d> in <module>
----> 1 img = make_weight_map(img)
<ipython-input-31-e75a6281476f> in make_weight_map(masks)
34 xSum = (X2.reshape(-1, 1) - X1.reshape(1, -1)) ** 2
35 ySum = (Y2.reshape(-1, 1) - Y1.reshape(1, -1)) ** 2
---> 36 distMap[:, i] = np.sqrt(xSum + ySum).min(axis=0)
37 ix = np.arange(distMap.shape[0])
38 if distMap.shape[1] == 1:
MemoryError:
主要问题出现在这一行中,因为X2的形状是(15239,1)
,X1的形状是(1329960)
,所以首先它必须执行一个庞大的广播操作
distmap,我无法计算,因为在此之前我的代码暂停。另外,如果我尝试对上述维度执行以下减法操作,代码也会在那里停止
X2.reshape(-1, 1) - X1.reshape(1, -1)
我使用的是32 Gb内存的系统,我还尝试在64 Gb内存的云上运行。
我已经检查了以下问题,要么它们没有提供我问题的解决方案,要么我无法应用到我的用例中
错误在哪里?回溯?如果您告诉我们此时数组的大小,
distMap
,X2
,等等,这会有所帮助。考虑到错误表达式,我怀疑问题只是许多大型数组的累积,有些是暂时的。此时您没有创建过大的数组。您好,我在问题中添加了一些其他信息,请检查。
X2.reshape(-1, 1) - X1.reshape(1, -1)