我想多次切出数组Inside Subject.js:
const SubjectSchema = new Schema({
topics: [{
type: Schema.Types.ObjectId,
ref: 'topic'
}]
...
的部分内容。目前我正在使用for循环，我希望通过矩阵计算替代它以在速度方面获得更好的性能。
foo这是我目前的做法。
foo = np.arange(6000).reshape(6,10,10,10)
target = np.zeros((100,6,3,4,5))
startIndices = np.random.randint(5, size=(100))
我试图将切片表示为数组，但我无法找到正确的表示。
答案 0 :(得分：3)
我们可以利用基于np.lib.stride_tricks.as_strided的scikit-image's view_as_windows进行有效的补丁提取，就像这样 -
from skimage.util.shape import view_as_windows
# Get sliding windows (these are simply views)
WSZ = (1,3,4,5) # window sizes along the axes
w = view_as_windows(foo,WSZ)[...,0,:,:,:]
# Index with startIndices along the appropriate axes for desired output
out = w[:,startIndices, startIndices, startIndices].swapaxes(0,1)
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