SimPEG.utils.estimate_diagonal#
- SimPEG.utils.estimate_diagonal(matrix_arg, n, k=None, approach='Probing')[source]#
Estimate the diagonal of a matrix.
This function estimates the diagonal of a matrix using one of the following iterative methods:
Probing: cyclic permutations of vectors with 1’s and 0’s (default)
Ones: random +/- 1 entries
Random: random vectors with entries in the range [-1, 1]
The user can estimate the diagonal of the matrix by providing the matrix, or by providing a function hangle which computes the dot product of the matrix and a vector.
For background information on this method, see Bekas (et al., 2005) and Selig (et al., 2012)
- Parameters
- matrix_arg
numpy.ndarray
orfunction
The matrix as a
numpy.ndarray
, or a function handle which computes the dot product between the matrix and a vector.- n
int
The length of the random vectors used to compute the diagonal; equals number of columns
- k
int
Number of vectors to be used to estimate the diagonal; i.e. number of iterations in estimation
- approach
str
Method used for approximating diagonal. Must be one of {‘probing’, ‘ones’, ‘random’}
- matrix_arg
- Returns
numpy.ndarray
Estimate of the diagonal elements of the input matrix