  It has been recently reported that classical systems have speed limit for
state evolution, although such a concept of speed limit had been considered to
be unique to quantum systems. Owing to the speed limit for classical system,
the lower bound for calculation time of simulated annealing with desired
calculation accuracy can be derived. However, such a lower bound does not work
as a criterion for completion of calculation in a practical time. In this
paper, we derive an inequality for classical system analogous to the quantum
adiabatic theorem that gives calculation time for an accuracy-guaranteed
fluctuation-exploiting computation. The trade-off relation between calculation
time and accuracy is given in the form tolerable in practical use.
