Jomini creates military simulations by using mathematical combat models. Designed to be helpful for game developers, students, history enthusiasts and -to some extent- scientists. You can mail me at [email protected] if you want to contribute.

To download: https://pypi.org/project/Jomini

Documentation will be available in the next update.

This package uses the combat models developed by Frederick William Lanchester, a.k.a one of the founding fathers of Operations Research.

• Lanchester Models are deterministic, which means the model will always yield the same result for the same input parameters.
• Lanchester Models view battles as an attrition model, therefore manuevers and sudden changes during the battle can not be represented.
• You might need to do some manual fine-tuning if you are not able to get quality parameters (rho, beta, engagement_width) from a data set.
• Despite the downsides, even the primitive models developed by Lanchester himself works wonders with the right parameters.

• The Linear Law is based on force concentration
• Good for modelling melee battles and unaimed fire (artillery, arquebus, handcannon etc.)

from jomini.Lanchester import Battle, LinearLaw

# Re-creating the Battle of Cerignola (AD 1503)
# In the actual battle, Spanish(red) lost 500 men while the French(blue) lost 4000 men
# Parameters rho, beta, engagement_width and time are manually fine_tuned
b = Battle(red=6_300, blue=9_000, rho=0.0800, beta=0.0100)
L = LinearLaw(b, engagement_width=100)
print(L.get_casualty_rates()) # Returns casualty rates 
print(L.get_casualties(time=7))
print(L.get_remaining(time=7))
print(L.simulate_battle(time=7))

• Square Law: Given equal power coefficients, the fighting power is proportional to the square of army size.
  • Good for modelling aimed fire (e.g Napoleonic line-battles)
• Logarithmic Law: Basically square law at a larger scale, used by Weiss to model the American Civil War
  • Good for modelling tank combat as well

from jomini.Lanchester import Battle, LinearLaw, SquareLaw, LogarithmicLaw, GeneralLaw

# Simulating a fictitious battle with each of the laws
b = Battle(red=20_000, blue=30_000, rho=0.0150, beta=0.0120)
Linear = LinearLaw(b, engagement_width=500)
Square = SquareLaw(b)
Log = LogarithmicLaw(b)
Generalized = GeneralLaw(b, engagement_width=500, p=0.450, q=0.600)

# If time is not specified, the battle goes on until one side is annihilated.
print(Linear.simulate_battle() + "\n")
print(Square.simulate_battle() + "\n")
print(Log.simulate_battle() + "\n")
print(Generalized.simulate_battle())