GNU Octave currently has the following Krylov subspace methods for sparse linear systems: pcg (spd matrices) and pcr (Hermitian matrices), bicg,
bicgstab, cgs, gmres, and qmr (general matrices). The description of some of them (pcr, qmr) and their error messages are not aligned. Moreover, they have similar blocks of code (input check for instance) which can be written once and for all in common functions. The first step in this project could be a revision and a synchronization of the codes, starting from the project SOCIS2016,
whole latest patch, still to be included, is [https://savannah.gnu.org/patch/?9108 here].
In Matlab, some additional methods are available: minres and symmlq (symmetric matrices), bicgstabl (generale matrices), lsqr (least