differences between scipy.sparse.linalg.lsmr and scipy.sparse.linalg.lsqr

Question

Does anybody know when is better to choose which? They seem the same to me...

lsmr lsqr

Answer 1

Both packages do the same. LSMR is based on Fong & Saunders algorithm from 2010 (see paper), and has been introduced in scipy very recently (ie, version 0.10 and earlier won't have it). According to the paper, LSMR should converge faster than LSQR, which uses the Paige & Saunders algorithm that has been around for almost 30 years.