XtalOpt Version r12: An open-source evolutionary algorithm for crystal structure prediction

Version 12 of XtalOpt, an evolutionary algorithm for crystal structure prediction, is now available for download from the CPC program library or the XtalOpt website, http://xtalopt.github.io. The new version includes: a method for calculating hardness using a machine learning algorithm within AFLOW-ML (Automatic FLOW for Materials Discovery — Machine Learning), the ability to predict hard materials, a generic optimizer (which allows the user to employ many optimizers that were previously not supported), and the ability to generate simulated XRD (X-ray diffraction) patterns