beezdemand_calc_pmax_omax: Calculate Pmax and Omax with Method Reporting and...

In beezdemand: Behavioral Economic Easy Demand

Calculate Pmax and Omax with Method Reporting and Parameter-Space Safety

Description

Unified internal engine for pmax/omax computation. Supports analytic solutions (Lambert W for HS/hurdle, closed-form for SND), numerical fallback, and observed (row-wise) metrics. Handles parameter-space conversions transparently.

Usage

beezdemand_calc_pmax_omax(
  model_type = NULL,
  params = NULL,
  param_scales = NULL,
  expenditure_fn = NULL,
  demand_fn = NULL,
  price_obs = NULL,
  consumption_obs = NULL,
  tol = 0.1,
  compute_observed = NULL
)

Arguments

model_type	Character: "hs", "koff", "hurdle", "hurdle_hs_stdq0", "snd", "simplified", or NULL
params	Named list of parameters. Names depend on model_type: hs/koff: alpha, q0, k hurdle: alpha, q0, k (note: hurdle uses different formula) hurdle_hs_stdq0: alpha, q0, k (Q0 appears inside exponent) snd/simplified: alpha, q0
param_scales	Named list mapping parameter names to their input scales: "natural", "log", or "log10". Default assumes all natural.
expenditure_fn	Optional function E(p) for numerical fallback. If NULL and model_type is provided, will be constructed from params.
demand_fn	Optional function Q(p) for elasticity calculation.
price_obs	Numeric vector of observed prices (required for observed metrics and domain constraints).
consumption_obs	Numeric vector of observed consumption (for observed metrics).
tol	Tolerance for unit elasticity check (default 0.1).
compute_observed	Logical; compute observed metrics? Default TRUE if price_obs and consumption_obs are provided.

Value

A list with snake_case fields:

pmax_model

Model-based pmax

omax_model

Model-based omax

q_at_pmax_model

Quantity at pmax

method_model

Method used: "analytic_lambert_w", "analytic_snd", "numerical_optimize_observed_domain"

domain_model

Price domain used for computation

is_boundary_model

Logical; is pmax at domain boundary?

elasticity_at_pmax_model

Elasticity evaluated at pmax

unit_elasticity_pass_model

Logical; is elasticity near -1?

note_model

Any notes about model computation

pmax_obs

Observed pmax

omax_obs

Observed omax

method_obs

Method for observed: "row_wise_max"

tie_break_obs

Tie-break rule: "min_price"

n_obs_rows

Number of observation rows

n_unique_prices

Number of unique prices

has_duplicate_prices

Logical; duplicate prices detected?

n_max_ties

Number of rows achieving omax

note_obs

Notes about observed computation

alpha_scale_in

Input scale for alpha

q0_scale_in

Input scale for Q0

k_scale_in

Input scale for k (if applicable)

note_param_space

Notes about parameter conversions

Examples

result <- beezdemand_calc_pmax_omax(
  model_type = "hs",
  params = list(alpha = 0.001, q0 = 10, k = 3),
  price_obs = c(0, 0.5, 1, 2, 4, 8, 16),
  consumption_obs = c(10, 9, 8, 6, 3, 1, 0)
)
result$pmax_model
result$omax_model

beezdemand documentation built on March 3, 2026, 9:07 a.m.