Explanations

These are developer-focused explanations of internal pylcm mechanisms. They are designed for contributors and advanced users who want to understand how pylcm works under the hood.

• Function Representation — What the function representation does and how it works.

• Interpolation and Extrapolation — How pylcm’s coordinate finders and map_coordinates handle interpolation and extrapolation across grid types.

• Approximating Continuous Shocks — Quadrature rules and Markov chain approximations for IID and AR(1) shock processes.

• Stochastic Transitions — Why regime, discrete state, and continuous shock transitions use different runtime representations.

• Dispatchers — How productmap, vmap_1d, and simulation_spacemap evaluate scalar functions on structured spaces.

• The Phase Grammar — How Phased(solve=..., simulate=...) gives regime slots per-phase variants, with carried states as the flagship use.

• Beta-Delta (Quasi-Hyperbolic) Discounting — How to use the plugin system to model consumers with this particular form of time-inconsistent preferences.

• Discrete-Continuous Choice: Iskhakov et al. (2017) — Why discrete choices produce saw-tooth consumption functions, illustrated on the paper’s retirement model, with a brute-force vs DC-EGM accuracy comparison.

• Internal Architecture — Map of the source tree, the user/engine boundary, and the role each package plays.