  After a brief review of the Fermi-Pasta-Ulam (FPU) conservative system of N
nonlinearly coupled oscillators, this paper addresses two problems: first,
comparing two indicators for the equipartition, showing that the results are
essentially identical; second, finding a method that allows fast integration to
reach the long integration times required in this area. In particular this work
proposes a symplectic algorithm based on the Fast Fourier Transform.
