Figure 5.

Number of lines of code available to different disease models, stratified by level of the inheritance hierarchy. Code was analyzed in February 2018 using Code surveyor by Construx Software, omitting lines that were blank or contained only comments. The common framework, sufficient to implement Generic SEIRS transmission and inherited by all other disease types, occupies 34 512 lines of code (dark blue bars). Cross-hatched areas indicate code that specifies transmission modality. Colored regions show disease specific code, which over-writes SEIRS with disease-specific states and interventions. As of this writing, no disease exceeds 50 000 lines of code. The vast majority of model code is devoted to the common framework, allowing for sharing of features and test cases across disease research.