Ability to perform Lanczos on a sparse Hamiltonian matrix.
Ability to perform Lanczos on a sparse Hamiltonian matrix.

Quick tests show that, due to sparsity, it is *far* cheaper (in terms of
memory required per node) to run a serial Lanczos with a sparse matrix
than to distribute the Hamiltonian matrix over many nodes using BLACS
and ScaLAPACK.

hande-qmc/hande,hande-qmc/hande,hande-qmc/hande,hande-qmc/hande,ruthfranklin/hande,hande-qmc/hande