v1.2.1

What's new

Added

• New SEIAR backbone model: symptomatic + asymptomatic infectious compartments, with parameters asymptomatic_fraction, asymptomatic_recovery_rate, and asymptomatic_relative_infectivity.
• Three orthogonal modular extensions composable on any backbone via load_predefined_model flags:
  • waning_immunity=True — adds R → S transition (SIRS, SEIRS dynamics); waning_rate defaults to 1/365 (~1 year of immunity)
  • vaccination=True — adds a Vaccinated compartment with S → V → I at reduced rate controlled by vaccine_efficacy
  • outcome="deaths" or outcome="hospitalization" — adds Dead or Hospitalized compartment branching from Infected
• SUPPORTED_MODELS updated to ["SIR", "SEIR", "SIS", "SEIAR"].
• All new rate parameters accept scalars, 1D time-varying arrays (T,), or 2D age-stratified arrays (T, G).
• Tutorial 12: Predefined Epidemic Models — demonstrates all backbones and modular extensions.

Fixed

• create_default_initial_conditions now correctly seeds all new model combinations: deduplicates transition sources, excludes accumulator compartments (Vaccinated, Exposed, Hospitalized, Dead) from initial population, and handles waning-immunity models where Susceptible is both a source and a target.