added lanczos lda1b code.
further tests are successfull against fulled codes.
small update in the routines naming to separate Lanczos and Complete ED algorithms.
-some working on the local Spin susceptibility.
-ready to include list for eigenstates and sparse matrices in Lanczos routines.
introduced list for the groundstate (and later on for all states contributing to the trace).
code tested against FullED results: ok.
some modifications requried in the EIG_SPACE module to minimize memory usage a pointer function
is used to point to the n-th groundstate vector
IMPORTANT: code has been updated a lot and thoroughly tested for the HM-Bethe case.
Sparse matrix structure introduced in the code and tested. Improve speed and
memory management.
A version (soon to be pre-compiled) using direct Hamiltonian product H*v, so not
storing the matrix itself, is written and tested but appears to be significantly
slower.
GETGF got a major improvement, with subdivision in routines building the GF, both for
the full and lanczos case.
DIAG/VARS_GLOBAL got several improvements concerning the maps and arrays used to
go forth and back the total Hilbert space. Although this solution is still unsatisfactory
on a general ground, a look-up table is very much desirable at this point, modifications
improve memory usage.
BATH is now randomly guessed.
Nimp-->Norb, ready to go multi-band that is easy now.
N-->Ntot to avoid problems in variables naming.