4.7 Discrete Event Simulations

MicroCity has a inside simulation time counting and event scheduling mechanism. It provides several embedded Lua functions to facilitate creating Discrete Event Simulations, which is very useful for dynamic system analysis. Sample codes for this chapter can be found in the "simulation_samples" folder of the Project Tab in ScriptEditor.

Random Number Generation

CreateRandEng (seed, "uniform_01")

Creates a binary distributed random generation engine from a seed and returns the object.

CreateRandEng (seed, "uniform_real" [, min = 0, max = 1])

Creates a uniform distributed real random generation engine from a seed and returns the object.

CreateRandEng (seed, "uniform_int" [, min = 0, max = 1])

Creates an uniform integer random generation engine from a seed and returns the object.

CreateRandEng (seed, "triangle" [, a = 0, b = 1, c = 2])

Creates a triangle distributed random generation engine from a seed and returns the object.

CreateRandEng (seed, "bernoulli" [, p = 0])

Creates a bernoulli distributed random generation engine from a seed and returns the object.

CreateRandEng (seed, "cauchy" [, median = 0, sigma = 1])

Creates a cauchy distributed random generation engine from a seed and returns the object.

CreateRandEng (seed, "exponential" [, lambda = 1])

Creates a exponential distributed random generation engine from a seed and returns the object.

CreateRandEng (seed, "geometric" [, p = 0])

Creates a geometric distributed random generation engine from a seed and returns the object.

CreateRandEng (seed, "normal" [, mean = 0, sigma = 1])

Creates a normal distributed random generation engine from a seed and returns the object.

CreateRandEng (seed, "lognormal" [, mean = 0, sigma = 1])

Creates a lognormal distributed random generation engine from a seed and returns the object.

GetNextRandom (Engine)

Gets a random number from a random generation engine.

Simulation Control

CreateEvent (time, Funcion [, arg1, arg2, ...])

Creates a future event from a Lua Function or a Lua Coroutine. Returns a Coroutine object.

ExecAllEvents ()

Calls this at last. It will execute all events as Lua Coroutines.

Delay ([relativeTime = 0])

Calls this function in a Lua Coroutine will let it first yield then resume it after the specified relative time. If the parameter relativeTime is not set, the current Coroutine will yield and won' be resumed automatically.

Resume ([time, ] Coroutine [, arg1, arg2, ...])

Resumes a yielded coroutine immediately or at a specified time.

GetSimTime ()

Returns the current simulation time.