Remove extrapolation abort. Increasing solver precision helps avoid these problems.
find_ground() - handle 0 CG_gap case properly.
Fix cg to restore CF when resetting. Add gap to opt_grad_desc, since it benefits it greatly.
Plain CG does not need it now. Rename some stuff.
Remove a bunch of unused CG stuff. Fix some bugs in the process.
Use already found iterative solutions in more cases.
Cleanup CG, renaming some variables and removing some cruft.
Add QR-based restore_CF functions.
Use QR-based restore_CF by default in mps_gen.
tdvp_gen: Save per site eta-squared contributions in eta_sq. eta = (eta_sq.sum())^0.5
Make calculating the inverse optional in herm_fac_with_inv.
Avoid inverting non-diagonal matrices in restore_SCF.
Modify vari_opt_sweep to use QR gauge transformation.
Clean up vari_opti_sweep some more.
Add an implementation of the integrator from arXiv:1408.5056 (one-site variant).
At the moment it depends on a f2py'd expokit and is set for imaginary time evolution.
The non-symmetric solvers would be needed for real time, I suppose.