TypeError:稀疏矩阵长度不明确；在scipy中调用lil_matrix.diagonal()时使用getnnz()或shape[0]
TypeError:稀疏矩阵长度不明确；在scipy中调用lil_matrix.diagonal()时使用getnnz()或shape[0]
提问于 2022-06-15 09:35:35
我试图用以下代码求出存储在矩阵格式中的稀疏矩阵的对角线之和：
sm1 = np.sum(board.diagonal(k=i1-row1))
sm2 = np.sum(board.diagonal(k=i2-row2))不过，这给了我一个
TypeError: sparse matrix length is ambiguous; use getnnz() or shape[0]type(board)返回<class 'scipy.sparse._lil.lil_matrix'>
row1, row2, i1, i2都是整数。有趣的是，如果我调用print(np.sum(board.diagonal(k=i1-row1))，它会在抛出类型错误之前打印正确的结果。
我怀疑该错误与向csr矩阵的转换有关，因为错误消息中提到了return self.tocsr().diagonal(k=k)，调用board.tocsr()会引发相同的错误。
提前感谢！
以下是整个错误日志：
Traceback (most recent call last):
File "/usr/lib/python3.8/code.py", line 90, in runcode
exec(code, self.locals)
File "<input>", line 1, in <module>
File "/snap/pycharm-professional/285/plugins/python/helpers/pydev/_pydev_bundle/pydev_umd.py", line 198, in runfile
pydev_imports.execfile(filename, global_vars, local_vars) # execute the script
File "/snap/pycharm-professional/285/plugins/python/helpers/pydev/_pydev_imps/_pydev_execfile.py", line 18, in execfile
exec(compile(contents+"\n", file, 'exec'), glob, loc)
File "/home/noah/PycharmProjects/nQueens/sa_sparse.py", line 94, in <module>
y.run()
File "/home/noah/PycharmProjects/nQueens/sa_sparse.py", line 63, in run
self.swap(newSol)
File "/home/noah/PycharmProjects/nQueens/sa_sparse.py", line 34, in swap
newCost = self.calcFastCost(board.board, row1, row2)
File "/home/noah/PycharmProjects/nQueens/sa_sparse.py", line 47, in calcFastCost
sm1 = np.sum(board.diagonal(k=i1-row1))
File "/home/noah/nQueens/lib/python3.8/site-packages/scipy/sparse/_base.py", line 1214, in diagonal
return self.tocsr().diagonal(k=k)
File "/home/noah/nQueens/lib/python3.8/site-packages/scipy/sparse/_lil.py", line 459, in tocsr
_csparsetools.lil_get_lengths(self.rows, indptr[1:])
File "_csparsetools.pyx", line 111, in scipy.sparse._csparsetools.lil_get_lengths
File "_csparsetools.pyx", line 117, in scipy.sparse._csparsetools._lil_get_lengths_int32
File "/home/noah/nQueens/lib/python3.8/site-packages/scipy/sparse/_base.py", line 345, in __len__
raise TypeError("sparse matrix length is ambiguous; use getnnz()"
TypeError: sparse matrix length is ambiguous; use getnnz() or shape[0]回答 1
Stack Overflow用户
发布于 2022-06-15 15:14:57
你的scipy版本是什么？在当前的设置中，我可以创建一个lil并得到对角线：
In [16]: M = sparse.lil_matrix(np.eye(3))
In [17]: M
Out[17]:
<3x3 sparse matrix of type '<class 'numpy.float64'>'
with 3 stored elements in List of Lists format>
In [18]: M.A
Out[18]:
array([[1., 0., 0.],
[0., 1., 0.],
[0., 0., 1.]])转换为csr没有问题，对角线也没有问题：
In [19]: M.tocsr()
Out[19]:
<3x3 sparse matrix of type '<class 'numpy.float64'>'
with 3 stored elements in Compressed Sparse Row format>
In [20]: M.diagonal()
Out[20]: array([1., 1., 1.])但是问len，确实会给你带来错误：
In [21]: len(M)
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
Input In [21], in <cell line: 1>()
----> 1 len(M)
File ~\anaconda3\lib\site-packages\scipy\sparse\base.py:291, in spmatrix.__len__(self)
290 def __len__(self):
--> 291 raise TypeError("sparse matrix length is ambiguous; use getnnz()"
292 " or shape[0]")
TypeError: sparse matrix length is ambiguous; use getnnz() or shape[0]对于这个lil，其他步骤很好：
In [22]: M.nnz
Out[22]: 3
In [23]: M.getnnz()
Out[23]: 3
In [24]: M.shape
Out[24]: (3, 3)lil将值存储在两个对象dtype数组中：
In [26]: M.data
Out[26]: array([list([1.0]), list([1.0]), list([1.0])], dtype=object)
In [27]: M.rows
Out[27]: array([list([0]), list([1]), list([2])], dtype=object)如果我删除一个rows元素破坏矩阵，就会得到一个完全不同的错误。
看起来这个错误发生在tocsr中，在这个块中，它根据rows元素的长度创建rows：
M, N = self.shape
if M*N <= np.iinfo(np.int32).max:
# fast path: it is known that 64-bit indexing will not be needed.
idx_dtype = np.int32
indptr = np.empty(M + 1, dtype=idx_dtype)
indptr[0] = 0
_csparsetools.lil_get_lengths(self.rows, indptr[1:])
np.cumsum(indptr, out=indptr)
nnz = indptr[-1]lil_get_lengths是经过编译的代码，它通过rows的元素并将它们的长度放在第二个参数中。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/72629046
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