testing the Lanczos multi-band case. Hubbard model.
first lanczos multi-orbital debug completed.
Hubbard mode give the very same results as single-band code.
Small issues found that should be fixed also in the single-band version:
1. the pointer to groundstate vector should be nullified inside the izero loop over
degenerate groundstate sectors. This is because something can happen to the vector (
manipulating the pointer will affect the vector itself).
This created problem with the calculation of observables in the multi-band code. FIXED.
2. evaluation of GF in lanczos, by adding contribution from particle and hole excitations
was reverted to old-style, for precaution reasons.
3. changed the printing information system within ED_GETOBS. This should allow for
a better data manipulation.
4. IMPORTANT. I noticed that (P)ARPACK has a problem (error exit with floating overflow)
when code is compiled with debugging option and we use normal (non-debugging) libraries.
I am investigating this point.