Worked examples¶

Seven worked-out model folders ship with the source tree under examples/. Each folder is self-contained:

a common.mod with the shared declarations, model and steady_state_model, included via @#include by each scenario,
one or more scenario .mod files that differ only in their initval, shocks and simulate blocks,
a run_*.py script that solves every scenario through the Python API and writes an overlaid plot,
a README.md presenting the model, the experiments and the simulation results, with embedded plots.

Run any scenario with the CLI or the API exactly as in the Quick start. The list below points at the headline result of each.

Saddle-path models (one state + one jump)¶

examples/rbc/: Ramsey/RBC with two state variables (capital and an Ornstein– Uhlenbeck productivity process), one jump (consumption) and one algebraic (output). Showcases the multi-segment surprise machinery (rbc_anticipated vs rbc_surprise) and the e={…} anchor (rbc_sustained).
examples/dornbusch/: Dornbusch (1976) exchange-rate overshooting. Sticky price (state) + exchange rate (jump). Shows the classic impact overshoot under an unanticipated monetary expansion; anticipated and gradual variants dampen it.
examples/tobinq/: Tobin’s q investment with convex adjustment costs. Capital (state) + shadow value q (jump) + investment (algebraic). Anticipated vs surprise vs unanticipated profitability shocks; q jumps at the reveal time.

examples/cagan/: Cagan model of money and prices: a single jump (the price level) driven by an exogenous money path. Prices LEAD anticipated money; the surprise variant shows prices flat until the reveal. Headline showcase for the shock-shape helpers (step, ramp).
examples/nk/: Continuous-time New Keynesian liquidity trap (Werning, 2011). Output gap and inflation (both jumps); the policy rate is max(0, …) — an occasionally-binding ZLB. A longer expected trap deepens today’s recession (forward-looking amplification).

examples/solow/: Solow–Swan growth: one state (capital), no jump. The simplest example; scenarios are convergence-from-below, a permanent savings-rate rise, and a permanent productivity rise.
examples/goodwin/: Goodwin (1967) growth cycle: a Lotka–Volterra system in two states (employment and the wage share). The interior fixed point is a centre, so the trajectory is a closed orbit — there is no terminal boundary condition (no jumps to anchor) and history alone pins the path. Scenarios vary the initial amplitude.

Each folder’s README has the model equations, parameter values, references, and a brief discussion of the simulated dynamics.