Interface to Certara's Nonlinear Mixed-Effects (NLME) modeling engine ('NLME-Engine') for pharmacokinetic and pharmacodynamic (PK/PD) modeling and simulation. Provides access to the Maximum Likelihood estimation algorithms available in the Phoenix NLME platform for population, individual, and pooled analyses using parametric methods. Includes utilities for setting up NLME installations and parallel settings, running estimation, bootstrap, and covariate search workflows, and updating model files from engine output. Jobs can be executed locally or across high-performance computing resources, including Linux Sun Grid Engine (SGE) and Simple Linux Utility for Resource Management (SLURM) grids as well as multicore Linux and Windows hosts.