Introduced Lanczos ED from IETL library
Created by: awietek
Dear all,
I wrote a wrapper for using the IETL Lanczos code (http://alps.comp-phys.org/static/doc2.1.0/ietl.html). The ground state energy computation in NetKet would now be done with this library. Probably we should discuss some more detailed user interface for the algorithm (how to set parameters, like precision for the Lanczos iteration. There are also some test, which could be extended.
Best, Alex