This keyword sets the number of generations \(N_\mathrm{gen}\) for the SNES algorithm [Schaul2011]. The syntax is:

generation <number_of_generatinons>

Here, <number_of_generations> sets \(N_\mathrm{gen}\), which must satisfy \(0 \leq N_\mathrm{gen}\leq 10^7\) and defaults to \(N_\mathrm{gen}=10^5\). For simple systems, \(N_\mathrm{gen}= 10^4 \sim 10^5\) is enough. For more complicated systems, values in the range \(N_\mathrm{gen} = 10^5\sim10^6\) can be required to obtain a well converged model.