The bootstrap resampling method may be efficiently used to estimate the generalization error of nonlinear regression models, as artificial neural networks. Nevertheless, the use of the bootstrap implies a high computational load. In this paper we present a simple procedure to obtain a fast approximation of this generalization error with a reduced computation time. This proposal is based on empirical evidence and included in a suggested simulation procedure.
Simon, G., Lendasse, A., & Verleysen, M. (2003). Bootstrap for model selection: linear approximation of the optimism. Lecture Notes in Computer Science, 2686, 182-189. https://doi.org/10.1007/3-540-44868-3_24 (Original work published 2003)