这是什么意思: Lk[:,rk] = -(lk.reshape(-1,1)) Lk[rk,:] = -(lk.reshape(1,-1))
时间: 2023-08-18 11:10:33 浏览: 45
这是Python代码,其中`Lk`是一个二维数组,`lk`是一个一维数组,`rk`是一个整数。
这段代码的作用是将`Lk`的第`rk`列和第`rk`行的元素都设置为`-lk`。具体解释如下:
- `lk.reshape(-1,1)`将`lk`转换为一个列向量(即只有一列)。
- `lk.reshape(1,-1)`将`lk`转换为一个行向量(即只有一行)。
- `-(lk.reshape(-1,1))`将列向量中的每个元素取相反数,即对每个元素x,计算-y,其中y=-x。
- `-(lk.reshape(1,-1))`将行向量中的每个元素取相反数,即对每个元素x,计算-y,其中y=-x。
- `Lk[:,rk] = -(lk.reshape(-1,1))`将`Lk`的第`rk`列设置为列向量的值。
- `Lk[rk,:] = -(lk.reshape(1,-1))`将`Lk`的第`rk`行设置为行向量的值。
因此,这段代码的作用是将`Lk`的第`rk`列和第`rk`行都设置为`-lk`,即将对角线元素设置为`0`,而其他元素设置为`-lk`。
相关问题
转成matlab: npair = nbk[idx].shape[0] rk = (nbk[idx] == k).nonzero()[0] Lk = sp.sparse.lil_matrix((npair,npair)) Lk.setdiag(lk) Lk[:,rk] = -(lk.reshape(-1,1)) Lk[rk,:] = -(lk.reshape(1,-1)) Lk_tensor.append(sp.sparse.csr_matrix(Lk)) si_map[k] = idx
npair = size(nbk{idx}, 1);
rk = find(nbk{idx} == k);
Lk = sparse(npair, npair);
Lk(1:npair+1:end) = lk;
Lk(:,rk) = -repmat(lk', npair, 1);
Lk(rk,:) = -repmat(lk, 1, npair);
Lk_tensor{end+1} = csr_matrix(Lk);
si_map(k) = idx;
raise ValueError("Input must be >= 2-d.") ValueError: Input must be >= 2-d.
This error message indicates that the input provided to a function or method should be a matrix or an array with at least two dimensions. In other words, the input should have multiple rows and columns, rather than being a one-dimensional list or array.
To fix this error, you can modify the input so that it has at least two dimensions. For example, if you have a list of numbers, you can convert it to a 2D array using numpy:
```
import numpy as np
my_list = [1, 2, 3, 4, 5]
my_array = np.array(my_list).reshape(-1, 1)
```
This will create a 2D array with one column and five rows. If you need a different shape, you can adjust the reshape arguments accordingly. Once you have a 2D array, you can pass it to the function or method without encountering the ValueError.
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