  A method to accelerate the matrix-vector products of j-scheme nuclear
Shell-Model Configuration Interaction (SMCI) calculations is presented. The
method takes advantage of the matrix product form of the j-scheme
proton-neutron Hamiltonian matrix. It is shown that the method can speed up
unrestricted large-scale pf-shell calculations by up to two orders of magnitude
compared to previously existing related j-scheme method. The new method allows
unrestricted SMCI calculations up to j-scheme dimension 10^10 to be made in
more complex model spaces.
