If you actually want to simulate an economy, the answer is complex dynamic systems. Traditional static equilibrium models (like Computational General Equilibriu

If you actually want to simulate an economy, the answer is complex dynamic systems. Traditional static equilibrium models (like Computational General Equilibrium (CGE) or the not actually very dynamic Dynamic Stochastic General Equlibrium (DSGE) models) are pretty useless (they have all these 'nudging' variables to try and push things towards reality but the actual underlying methodology is bunk). Even weather forecasting moved to dynamical systems models decades ago, economics still hasn't caught up.