Version 0.4.2 includes a lot of work on the search space representation, application of restrictions, and optimization strategies. In addition to the addition of several new optimization strategies, most optimization strategies should see improved performance both in terms of the number of evaluated kernel configurations as well as execution time. Added new optimization strategies: dual annealing, greedly ILS, ordered greedy MLS, greedy MLS support for constant memory in cupy backend constraint solver to cut down time spent in creating search spaces support for custom tuning objectives support for max_fevals and time_limit in strategy_options of all strategies Removed alternative Bayesian Optimization strategies that could not be used directly C++ wrapper module that was too specific and hardly used Changed string-based restrictions are compiled into functions for improved performance genetic algorithm, MLS, ILS, random, and simulated annealing use new search space object diff evo, firefly, PSO are initialized using population of all valid configurations all strategies except brute_force strictly adhere to max_fevals and time_limit simulated annealing adapts annealing schedule to max_fevals if supplied minimize, basinhopping, and dual annealing start from a random valid config