从scipy CSR稀疏矩阵访问值，列索引和row_ptr数据 [英] Access value, column index, and row_ptr data from scipy CSR sparse matrix

问题描述

我有一个大的矩阵，希望将其转换为稀疏的CSR格式.

I have a large matrix that I would like to convert to sparse CSR format.

当我这样做时:

import scipy as sp
Ks = sp.sparse.csr_matrix(A)

print Ks

我在A密集的地方

 (0, 0) -2116689024.0
 (0, 1) 394620032.0
 (0, 2) -588142656.0
 (0, 12)    1567432448.0
 (0, 14)    -36273164.0
 (0, 24)    233332608.0
 (0, 25)    23677192.0
 (0, 26)    -315783392.0
 (0, 45)    157961968.0
 (0, 46)    173632816.0

等...

我可以使用以下方法获取行索引，列索引和值的向量:

I can get vectors of row index, column index, and value using:

Knz = Ks.nonzero()
sparserows = Knz[0]
sparsecols = Knz[1]

#The Non-Zero Value of K at each (Row,Col) 
vals = np.empty(sparserows.shape).astype(np.float)
for i in range(len(sparserows)):

    vals[i] = K[sparserows[i],sparsecols[i]]

但是可以提取稀疏CSR格式(值，列索引，行指针)中包含的向量吗?

But is it possible to extract the vectors supposedly contained in the sparse CSR format (Value, Column Index, Row Pointer)?

SciPy的文档解释说，可以从这三个向量生成CSR矩阵，但我想相反地将这三个向量取出.

SciPy's documentation explains that a CSR matrix could be generated from those three vectors, but I would like to do the opposite, get those three vectors out.

我想念什么?

感谢您的时间！

推荐答案

value = Ks.data
column_index = Ks.indices
row_pointers = Ks.indptr

我相信这些属性是未记录的，可能会使其发生变化，但是我已经在scipy的多个版本中使用了它们.

I believe these attributes are undocumented which may make them subject to change, but I've used them on several versions of scipy.

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