dask.array.diag

dask.array.diag(v)[source]

Extract a diagonal or construct a diagonal array.

This docstring was copied from numpy.diag.

Some inconsistencies with the Dask version may exist.

See the more detailed documentation for numpy.diagonal if you use this function to extract a diagonal and wish to write to the resulting array; whether it returns a copy or a view depends on what version of numpy you are using.

Parameters
varray_like

If v is a 2-D array, return a copy of its k-th diagonal. If v is a 1-D array, return a 2-D array with v on the k-th diagonal.

kint, optional (Not supported in Dask)

Diagonal in question. The default is 0. Use k>0 for diagonals above the main diagonal, and k<0 for diagonals below the main diagonal.

Returns
outndarray

The extracted diagonal or constructed diagonal array.

See also

diagonal

Return specified diagonals.

diagflat

Create a 2-D array with the flattened input as a diagonal.

trace

Sum along diagonals.

triu

Upper triangle of an array.

tril

Lower triangle of an array.

Examples

>>> x = np.arange(9).reshape((3,3))  
>>> x  
array([[0, 1, 2],
       [3, 4, 5],
       [6, 7, 8]])
>>> np.diag(x)  
array([0, 4, 8])
>>> np.diag(x, k=1)  
array([1, 5])
>>> np.diag(x, k=-1)  
array([3, 7])
>>> np.diag(np.diag(x))  
array([[0, 0, 0],
       [0, 4, 0],
       [0, 0, 8]])