Check for identifiability of fixed effects

Calculates the matrix of second-derivatives of the marginal likelihood with respect to fixed effects, to see if any linear combinations are not estimable (i.e. cannot be uniquely estimated conditional upon model structure and available data, e.g., resulting in a likelihood ridge and singular, non-invertable Hessian matrix)

Usage

check_estimability(obj, h)

Arguments

obj

The compiled object

h

optional argument containing pre-computed Hessian matrix

Value

A tagged list of the hessian and the message