• 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] < cutoff, reverse the permutation from pivoting and perform another QR decomposition to ensure that R is upper right.


A (numpy.ndarray) – Matrix to be decomposed as A = Q.R


Q, R – Decomposition of A into isometry Q^d Q = 1 and upper right R with diagonal entries larger than cutoff.

Return type: