May 3, 2026J/K move · Enter open · S save
Sejun Park, Yeachan Park, Geonho Hwang
Department of Artificial Intelligence, Korea University, Seoul, 02841, Republic of Korea · Department of Mathematics and Statistics, Sejong University, Seoul, 05006, Republic of Korea · Department of Mathematical Sciences, Gwangju Institute of Science and Technology, Gwangju, 61005, Republic of Korea
Theoretical studies show that for any differentiable function on a compact domain, there exists a neural network that approximates both the function values and gradients. However, such a result cannot be used in practice since it assumes real parameters and exact internal operations. In contrast, real implementations only use a finite subset of reals and machine operations with round-off errors. In this work, we investigate whether a similar result holds for neural networks under floating-point arithmetic, when the gradient with respect to the input is computed by the automatic differentiation algorithm
DAD. We first show that given a floating-point function
φ (e.g., a loss function), arbitrary function values and gradients can be represented by a floating-point network
f and
DAD(φ∘f), respectively. We further extend this result: given
φ1,…,φn,
DAD(φi∘f) can simultaneously represent arbitrary gradients while
f represents the target values, under mild conditions. Our results hold for practical activation functions, e.g.,
ReLU,
ELU,
GeLU,
Swish,
Sigmoid, and
tanh.