ABSTRACT
We begi n by showing that the momentum-conserving algorIthm cannot conserve energy , then show how i t can be adjusted so that it does. The algo rithm derived from the variat ional pr inc ip le fol lows this prescri pt ion and i n addi t ion provides the Poisson algor i thm. The loss o f momentum conserva t ion and the overal l accuracy of the variational procedure are discussed in the remaining sections. Al though the energy-conserving algorithms have not demonstrated superiority in practice, they have many interest ing properties .
