Abstract: In a numerical simulation, input data expressed in at least a first domain is received. The input data is transformed to generate frequency modes of the input data in frequency domain. The transformed data is down-sampled to retain a subset of the frequency modes in the frequency domain. The down-sampled data is successively processed with one or more stages of a neural network to generate a down-sampled output in the frequency domain. The processing includes applying, in each stage of the one or more stages, a non-linear transformation to the subset of the frequency modes. The down-sampled output is then up-sampled to generate an up-sampled output corresponding to the frequency modes in the frequency domain, and the up-sampled output is transformed from the frequency domain to the at least the first domain to generate a result of the numerical simulation.