Just read this very interesting article on compression of the wave function information using singular value decomposition of the full CI vector. The idea of factorizing the CI matrix can already be found in a paper by Koch and Dalgaard, however this earlier paper showed results for system with small number of electrons and basis sets and has a different purpose. As mentioned in the paper, the cost of the SVD step used in the compression step scales as , where is the size of the FCI space. This step actually costs a bit more (asymptotically) than what is required to evaluate the product of the Hamiltonian matrix times a trial vector.
August 21, 2013 Uncategorized