autopysta 0.0.3.11

2D traffic modeling.

Autopysta

Autopysta is a python library for modeling 2-D highway traffic, it's written natively on C++ for better performance and wrapped in SWIG to be used in Python

• Important

  Only Python 3.8 works on Windows, other versions are not working due to problems with the .dll

  For Linux you can use any version from Python 3.8 onwards and there's also legacy support for python 2.7

  The 3.8 version is al compatible with Google Colaboratory

• Details

  The package comes with a .so file (Linux), a .pyd file (Windows) and a .py that uses those files depending on your OS

  There is no Mac OS support at the moment, but an implementation is planned for future realeses

• How to use

  Installation

  You can install Autopysta using the pip installer

  pip install autopysta

  To begin using Autopysta you just need to import the module on Python:

  import autopysta

  And now you can use all the functions available on the library

• Examples

  A quick implementation of Autopysta:

  import autopysta as ap
  
  
  geo = ap.geometry(1000, 1, 0, 1000)
  
  newell = ap.newell()
  
  # Since this example doesn't use lane changes we use the no lane change as our model
  lcm = ap.no_lch()
  
  creators_list = [ap.fixed_state_creator(newell, 20, 10),]
  
  total_time = 120
  
  # total_time must be a multiple of dt
  dt = 1.2
  
  pre_made_vehicles = []
  
  # We run the simulation
  simulation = ap.simulation(lcm, total_time, geo, creators_list, pre_made_vehicles, dt)
  
  results = simulation.run()
  
  # And plot the results
  results.plot_x_vs_t()
  

  This gives us the following output :

  INITIAL STATE SIMULATION
[simulation.cpp] Out of loops, getting the answer ready

  And the plot :

• Functions

  Syntax	Description
  geometry(length, lanes, merge, diverge)	Set geometry of the simulated highway
  gipps()	Creates a Gipps model manager with default values
  lcm_gipps()	Creates a Gipps lane-changing model manager with default values
  lcm_gipps(p)	Creates a Gipps lane-changing model with a set of parameters
  newell()	Creates a Newell model manager with default values
  newell(p)	Create Newell model with a set of parameters
  p_gipps(an, bn, sn, vn, tau, bg)	Creates set of parameters with max acceleration, max deceleration, jam spacing, free-flow speed, reaction time, leader's max deceleration
  p_lcm_gipps()	Creates a Gipps lane-changing set of parameters with default values
  p_lcm_gipps(pvlow, pvhigh)	Creates a Gipps lane-changing set of parameters with free-flow speed to overtake and free-flow speed to change back to right lane
  p_newell(u, w, kj)	Creates set of parameters with free-flow speed, wave speed, jam density
  point(t, x, v, a, lane)	Point with initial time, position, speed, acceleration and lane
  simulation(d, T, g, c, dt)	Start simulation with lane changing model, total simulation, geometry, vehicle creator and timestep
  simulation.run()	Runs simulation object
  vehicle(hist_X, lane)	Create vehicle with only one lane and trajectory defined by every X in hist_X array
  vehicle(hist_X, lanes)	Create vehicle with multiple lanes allowed and trajectory defined by every X in hist_X array
  vehicle(hist_point)	Create a vehicle with a trajectory defined by an array of points (the points include their lane)
  vehicle(m, x, v, lane)	Create a vehicle with the model, initial postion, initial speed and initial lane
  vehicle(m, p)	Create a vehicle with initial model and point
  version()	Autopysta version

• Exceptions

  Autopysta has it's own set of custom exceptions written entirely in c++.

  To use them import AutopystaException from the autopysta module

  from autopysta import AutopystaException

  • Example

    import autopysta as ap
    from autopysta import AutopystaException
    
    #geometry's first parameter is length (which can't be smaller than 0)
    try:
        geo = ap.geometry(-100, 1, 30, 70)
    except AutopystaException as e:
        print(e)
    

    Running this code will throw the following exception:

    [autopysta module] [error #901]: Wrong parameters. Dt should be greater than zero.

  Types of exceptions:

  901 Wrong Parameters

  901
  1/wkj (tau) divided by dt must be an integer.
  1/wkj (tau) must be equal to dt.
  Check 0 < pvlow < pvhigh < 1
  Creator's spacing can't be negative, zero or less than jam spacing.
  Diverge should be less than length.
  Dt should be greater than zero.
  Fixed state creator's spacing can't be negative, zero or less than jam spacing.
  hist_X must be the same size as lanes
  Merge or diverge out of bounds.
  Merge should be greater than diverge.
  There must be as many creators as lanes.
  Time should be a multiple of dt
  Unfeasible Demand (flow < 1/dt)

  902

  902
  Division by zero

  903

  903
  Vehicle deltaTimes don't match

  904

  904
  Trajectory too short.

  908

  908
  Vehicle with given trajectory run out of points for the simulation

  909 Wrong Index

  909
  Can't extrapolate
  Can't return a point of the future