(A) ¹³C-Metabolic flux analysis (¹³C-MFA). Metabolic fluxes are determined by minimizing the difference between simulated and measured isotopic labeling patterns obtained from ¹³C-tracer experiments. (B) Flux balance analysis (FBA). Metabolic fluxes are calculated by maximizing a cellular objective function, such as cellular growth rate. (C) Kinetic modeling, metabolic fluxes, described as reaction kinetic equations, are determined by minimizing the difference between simulated and measured metabolite concentrations and fluxes. All three techniques use the stoichiometry matrix for ODEs describing the mass balances for the reacting species in the system (⁠$dc/dt=S⋅v$⁠). Formulations of only the basic methods for each technique are shown, and not those of advanced frameworks.