numpy.ma.identity(n, dtype=None) =
Return the identity array. The identity array is a square array with ones on the main diagonal. Parameters:
n : int Number of rows (and columns) in n x n output. dtype : data-type, optional Data-type of the output. Defaults to float. Returns:
out : ndarray n x n array with its main diagonal set to one, and all other elements 0. Examples >>> np.identity(3)
array([[ 1., 0., 0.],
[ 0., 1., 0.],
[ 0., 0., 1.]])