identicalsnowflake/transaction-simulation

A simple simulator for wealth transactions between players

Transaction simulation

This is a simple transaction simulation model which operates on four inputs: number of players, a transaction function, an iteration count, and an initial wealth distributor.

To run the simulation, make sure you have Haskell installed and simply do cabal sandbox init, cabal install, and cabal run.

Running the simulation will report a gini for the starting and ending worlds, as well as the starting and ending percentiles of the players who ended up the most wealthy.

Transaction function

A transaction function is a function MonadRandom m => (Wealth , Wealth) -> m (Wealth , Wealth), which means it's a function in the MonadRandom monad which accepts two wealth inputs, one for each party to the transaction, and returns two wealth outputs, again, one for each party.

-- example transaction function
-- | Transaction function where a random amount of wealth both parties can afford is gambled
randomLimitByNegotiatingPower :: MonadRandom m => (Wealth , Wealth) -> m (Wealth , Wealth)
randomLimitByNegotiatingPower (w1 , w2) = do

  v <- getRandomR (0.0 , min w1 w2)

  k :: Bool <- getRandom

  pure $ if k then (w1 + v , w2 - v) else (w1 - v , w2 + v)

Initial wealth

Initial wealth is simply a MonadRandom m => m Wealth:

genWealth :: MonadRandom m => m Wealth
genWealth =
  -- uniform wealth scale (low start gini)
  getRandomR (1000 , 2000000)