A 100% partial score is evidence that SMIRKY can generate the SMIRKS of the same chemical complexity found in the smirnoff99Frosst. As with SMARTY, we examine the partial score for each reference torsion type and consider the fraction of iterations spent at 100% (Figure ). For all but one reference torsion type (t2), SMIRKY is able to achieve a partial score of 100% for at least a fraction of time at all temperatures. It does achieve a 100% partial score for t2 at most temperatures, only failing at temperatures of 0 and 0.1. However, PhEthOH is slightly more challenging, as evidenced by the fact that heat map colors are lighter in general. Unlike in AlkEthOH, SMIRKY was not able to achieve a total score of 100% when sampling torsions in PhEthOH (Table ). PhEthOH only has six more torsion types, yet these make it substantially more challenging to find and keep sufficiently complex SMIRKS. In Section 3.1.1, we estimated the number of moves required to generate certain SMARTS patterns. When considering fragment types with more atoms, the combinatorial problem grows further since there are multiple atoms and bonds that require decorators. The lower frequency of 100% partial scores for torsions in PhEthOH is our first example of the implications of this combinatorial problem. For PhEthOH, we are able to generate SMIRKS for all reference torsions during at least some fraction of most simulations. However, if we are going to effectively sample chemical perception trees for the development of force fields, future move proposals will need to move through chemical space more efficiently. We will examine this problem more closely when analyzing SMIRKY's results on MiniDrugBank (Section 3.2.3).