Set up loglikelihood computations

[osorensen]

Overview

In C++, get the necessary data from R, and use this to compute the Laplace approximate log likelihood.

Intended outcome

Be able to evaluate the loglikelihood at given values of the fixed parameters, integrating over the random effects and the fixed regression coefficients.

Things to do

• Find and store fill-reducing permutation
• Update matrices with given lambda parameters.
• Get the right link functions with their derivatives.
• Solve linear system.
• Create unit tests at given parameter values.