Another challenge that CNN models of mass spectra face is that, because the CNN operates on vectors, the m/z axis of the MS2 spectra must be discretized prior to input. Choosing the bin size for this discretization is difficult. Large bins sacrifice precision in the m/z measurements, whereas small bins lead to very large inputs that are extremely sparse and require a significant amount of GPU memory to process. Small bins also yield larger edge effects, where two peaks in different spectra may have nearly identical m/z values but end up being separated by a bin boundary.