Build Inverse, Gradient, and grad_y Closures for a Model

Returns three closures (inv, grad, grad_y) that evaluate the inverse function, parameter gradient, and response-derivative for a given model. Used by error propagation via the delta method.

Usage

make_inv_and_grad_fixed(model, fixed_a = NULL)

Arguments

model

Character. One of "logistic4", "logistic5", "loglogistic4", "loglogistic5", "gompertz4".

fixed_a

Numeric scalar or NULL. If non-NULL, a is treated as a known constant and excluded from the parameter gradient.

Value

A list with closures: inv(y, p), grad(y, p), grad_y(y, p). Each accepts a response value y and named parameter vector p (from coef(fit)).