In order to search a large parameter space adequately, a large number of trials would be needed. Chemprop allows for parallel operation of multiple hyperparameter optimization instances, so that the entire set of trials does not need to be run in series. Parallel operation can be achieved by setting the location of trial checkpoint files with --hyperopt_checkpoint_dir to be a single shared location for multiple hyperparameter optimization instances. This allows for multiple instances of the program to share and contribute to the same trial history, reducing the wall time needed to perform hyperparameter optimization significantly.