Drug discovery is expensive. Computers are an important tool in combating this, because their computations can reduce the number of time-consuming physical tests needed. The use of computers in drug discovery is the subject of a great deal of research and we saw an example of this in the news last week when it was reported that a powerful new antibiotic had been discovered using artificial intelligence (see J. Stokes et al., “A Deep Learning Approach to Antibiotic Discovery”, Cell, vol. 180, no. 4, pp. 688-702.e13, 2020. Available: 10.1016/j.cell.2020.01.021, widely reported by the media).