Lanczos++ is a free and open source Hamiltonian code for strongly correlated electrons. It can use Lanczos and exact diagonalization to solve the models.
$ cd someDirectory/ $ git clone https://github.com/g1257/PsimagLite.git $ git clone https://github.com/g1257/LanczosPlusPlus.git $ cd PsimagLite/lib $ perl configure.pl (You may now edit Config.make) $ make $ cd ../../ $ cd LanczosPlusPlus/src $ perl configure.pl (You may now edit Config.make) $ make $ ./lanczos -f input0.inp
Lanczos takes the same inputs as DMRG++ but can only solve small systems. Documentation is in progress.