ISOpureS2.model_optimize.kappa.kappa_deriv_loglikelihood function
Compute derivative of loglikelihood with respect to kappa for step 2
Compute derivative of loglikelihood with respect to kappa for step 2
Computes the derivative of the part of the loglikelihood function relevant to optimizing kappa for step 2. Instead of performing constrained optimization on kappa directly, we optimize the log of kappa in an unconstrained fashion.