Model Catalogue

All models live in econ_viz.models and conform to the UtilityFunction protocol — they are callable dataclasses that evaluate U(x, y) element-wise over NumPy arrays.

Parametric models

Model	Expression	Class
Cobb-Douglas	\(x^\alpha y^\beta\)	CobbDouglas
Leontief	\(\min(ax, by)\)	Leontief
Perfect Substitutes	\(ax + by\)	PerfectSubstitutes
CES	\((\alpha x^\rho + \beta y^\rho)^{1/\rho}\)	CES
Satiation	\(-a(x-x^*)^2 - b(y-y^*)^2\)	Satiation
Quasi-Linear	\(f(x) + y\) or \(x + f(y)\)	QuasiLinear

Advanced models

Model	Description	Class
Custom Utility	Wrap any vectorised callable	CustomUtility
Multi-Good Cobb-Douglas	N goods, projected to 2-D	MultiGoodCD

Common interface

Every model exposes:

model(x, y)            # evaluate U(x, y) — accepts scalars or NumPy arrays
model.utility_type     # UtilityType.SMOOTH | KINKED | LINEAR
model.ray_slopes()     # list of expansion-path slopes
model.kink_points(lvls)# kink coordinates for Leontief-type preferences