As Inports are required for linearization, other inputs can be used in conjunction with a Sum block. During the linearization process, t remains a constant value of zero. The numerical algorithms on which linmod is based assume that the system nonlinearities are differentiable. This means they possess a Taylor series expansion. Complete accuracy would require the perturbation to be infinitesimal and the number of significant figures in the function evaluations to be infinite.
Errors arise due to the truncation of the higher order terms present in the Taylor series expansion.
Such errors are thus called truncation error. Since truncation error increases with perturbation size, the obvious remedy would seem to be to use the smallest perturbation possible. Alternatively, another source of error lies in the fact that computers have limited precision. Choosing the proper perturbation level is dependent on the situation. Double precision calculations eliminate many, but not all, of these problems.