Top panels: example of the input data (M(R) measurements with errors, left plot), and corresponding output data from ANN (p(ρ) relation, right plot) for the estimation of EOS from M(R). Both input samples consist of 20 observations with masses randomly selected from a mass distribution (Sect. 3.2) and measurement uncertainties equal to σ_M = 0.1 M_⊙, σ_R = 1 km (blue sample), σ_M = 0.01 M_⊙, σ_R = 0.01 km (red sample). For the description of the uncertainties on the output, see the text. Bottom panels: example of the input data (M(R̂) measurements with errors, left plot), and corresponding output data from ANN (p(ρ) relation, right plot) for the estimation of EOS from M(R̂). Both input samples consist of 20 observations with masses randomly selected from a mass distribution (Sect. 3.2) and measurement uncertainties equal to σ_M = 0.1 M_⊙, σ_R = 1 km (blue sample), σ_M = 0.01 M_⊙, σ_R̂ = 0.01 km (red sample). Dashed curves correspond to original (ground-truth, error-free) sequences of input and output of the TOV equations. Presented examples correspond to different EOSs.