我有一個數組,我反覆地建立類似如下:dask.array.reshape很慢
step1.shape = (200,200)
step2.shape = (200,200,200)
step3.shape = (200,200,200,200)
,然後重塑到:
step4.shape = (200,200**3)
我這樣做是因爲dask.array.atop似乎並不允許你從這樣的形狀出發:(200,200) - >(200,200 ** 2)。我認爲這與分塊和懶惰評估有關。
當我做step4並嘗試重塑它時,dask似乎想要在重塑它之前計算矩陣,這會導致顯着的計算時間和內存使用。
有沒有辦法避免這種情況?
按照要求,這裏是一些僞代碼:
def prod_mat(matrix_a,matrix_b):
#mat_a.shape = (300,...,300,200)
#mat_b.shape = (300, 200)
mat_a = matrix_a.reshape(-1,matrix_a.shape[-1])
#mat_a = (300**n,200)
mat_b = matrix_b.reshape(-1,matrix_b.shape[-1])
#mat_b = (300,200)
mat_temp = np.repeat(mat_a,matrix_b.shape[0],axis=0)*np.tile(mat_b.T,mat_a.shape[0]).T
new_dim = int(math.log(mat_temp.shape[0])/math.log(matrix_a.shape[0]))
new_shape = [matrix_a.shape[0] for n in range(new_dim)]
new_shape.append(-1)
result = mat_temp.reshape(tuple(new_shape))
#result.shape = (300,...,300,300,200)
return result
b = np.random.rand(300,200)
b = da.from_array(b,chunks=100)
c=da.atop(prod_mat,'ijk',b,'ik',b,'jk')
d=da.atop(prod_mat,'ijkl',c,'ijl',b,'kl')
e=da.atop(prod_mat,'ijklm',d,'ijkm',b,'lm')
f = e.sum(axis=-1)
f.reshape(300,300**3) ----> This is slow, as if it is using compute()
對不起,我不明白你的問題的步驟。你能否提供一個你試圖做的失敗或緩慢的示例操作?也許隨機數據? – MRocklin
我會將它添加到原始帖子中。 – simeon