Nonuniform binning

Figure 7. The distribution of lifetimes3 in SiH2(T fi,020) versus t/t( ). The solid line is the lit by (2.41) with v = 1. The histogrammic representation of the data uses nonuniform bins so as to emphasize the distribution at low r s. [The most probable r for v = 1 is at r( )/3.] All 222 measured levels were included in the fit but 14 levels have r > 20t( ) and hence are not included in the drawing.

After PPP type assignments, all interatomic distances are calculated and represented by the bins into whose distance ranges they fall. Six distances are needed to describe each combination of four PPP types. Seven or 10 nonuniform distance ranges (Table S23) were proposed to calculate 4-PPP keys since they were found to be the best trade-off among differentiation, resolution, and manageable descriptor size (e.g., around 5.6 million pharmacophore/molecule with 7 ranges and 24.4 million with 10 ranges). 

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