qr_li¶
full name: tenpy.tools.math.qr_li
parent module:
tenpy.tools.math
type: function
-
tenpy.tools.math.
qr_li
(A, cutoff=1e-15)[source]¶ QR decomposition with cutoff to discard nearly linear dependent columns in Q.
Perform a QR decomposition with pivoting, discard columns where
R[i,i] < cuttoff
, reverse the permututation from pivoting and perform another QR decomposition to ensure that R is upper right.- Parameters
A (
numpy.ndarray
) – Matrix to be decomposed asA = Q.R
- Returns
Q, R – Decomposition of A into isometry Q^d Q = 1 and upper right R with diagonal entries larger than cutoff.
- Return type