Version 1.9.0

Breaking changes

• (because prone to bug): force the environment name in the grid2op.make function.
• because bugged... The default behaviour for env.render() is now "rgb_array". The mode
  "human" has been removed because it needs some fixes. This should not impact lots of code.
• the "maintenance_forecast" file is deprecated and is no longer used (this should not
  not impact anything)
• the attribute "connected" as been removed in the edges of the observation converted as
  as a networkx graph. It is replaced by a "nb_connected" attribute. More information on the doc.
• the function "obs.as_networkx" will be renamed "obs.get_energy_graph" and the
  description has been adapted.
• In PandaPowerBackend the kwargs argument "ligthsim2grid" was misspelled and is now properly
  renamed lightsim2grid
• you can no longer use the env.reactivate_forecast() in the middle of an episode.
• the method runner.run_one_episode() (that should not use !) now
  returns also the total number of steps of the environment.

Fixed issues

• a bug in PandapowerBackend when running in dc mode (voltages were not read correctly
  from the generators)

• issue #389 which was caused by 2 independant things:

  1. the PandapowerBackend did not compute the theta correctly on powerline especially if
     they are connected to a disconnected bus (in this case I chose to put theta=0)
  2. the obs.get_energy_graph (previously obs.as_networkx()) method did not check,
     when updating nodes attributes if powerlines
     were connected or not, which was wrong in some cases

• the N1Reward that was broken

• the act._check_for_ambiguity: a case where missing (when you used topology to disconnect a powerline,
  but also set_bus to connect it)

• a bug when the storage unit names where not set in the backend and needed to be set
  automatically (wrong names were used)

• a bug in PandaPowerBackend when using BackendConverter and one the backend do not support shunts.

• 2 issues related to gym env: #407 and
  #418

• some bus in the obs.get_energy_graph (previously obs.as_networkx()) for the cooldowns of substation

• issue #396

• issue #403

• a bug in PandaPowerBackend when it was copied (the kwargs used to build it were not propagated)

• a bug in the Runner when the time series class used is not MultiFolder (eg GridStateFromFile): we could
  not run twice the same environment.

• a bug n the GridStateFromFile, GridStateFromFileWithForecasts and
  GridStateFromFileWithForecastsWithoutMaintenance classes that caused the maintenance file to be
  ignored when "chunk_size" was set.

• a bug when shunts were alone in backend.check_kirchoff()

• an issue with "max_iter" in the runner when MultifolderWithCache
  (see issue #447)

• a bug in MultifolderWithCache when seeding was applied

New features

• the function obs.get_forecast_env() that is able to generate a grid2op environment from the
  forecasts data in the observation. This is especially useful in model based RL.
• an example on how to write a backend.
• some convenient function of gridobject class to convert back and forth "local bus id" (1 or 2) to
  "global bus id" (0, 1, 2, ... 2*n_sub) [see gridobject.global_bus_to_local or gridobject.local_bus_to_global]
• a step by step (very detailed) example on how to build a Backend from an existing grid "solver".
• some test when the shunt bus are modified.
• a function to get the "elements graph" from the grid2op observation (represented as a networkx graph)
  as well as its description on the documentation.
• a method to retrieve the "elements graph" (see doc) fom an observation obs.get_elements_graph()
• a whole new way to deal with input time series data (see the module grid2op.Chronics.handlers
  for more information)
• possibility to change the parameters used for the obs.simulate(...)
  directly from the grid2op action, see obs.change_forecast_parameters()
• possibility to retrieve a "forecast environment" with custom forecasts, see
  obs.get_env_from_external_forecasts(...)
• now requires "importlib-metadata" package at install
• adding the TimedOutEnvironment that takes "do nothing" actions when the agent
  takes too much time to compute. This involves quite some changes in the runner too.
• Runner is now able to store if an action is legal or ambiguous
• experimental support to count the number of "high resolution simulator" (obs.simulate,
  obs.get_simulator and obs.get_forecast_env) in the environment (see
  #417). It might not work properly in distributed settings
  (if the agents uses parrallel processing or if MultiProcessEnv is used), in MultiMixEnv, etc.
• it now possible to check the some rules based on the definition of
  areas on the grid.

Improvments

• possibility to "chain" the call to simulate when multiple forecast
  horizon are available.
• the GridStateFromFileWithForecasts is now able to read forecast from multiple steps
  ahead (provided that it knows the horizons in its constructor)
• documentation of the gym DiscreteActSpace: it is now explicit that the "do nothing" action
  is by default encoded by 0
• documentation of BaseObservation and its attributes
• PandapowerBackend can now be loaded even if the underlying grid does not converge in AC (but
  it should still converge in DC) see #391
• obs.get_energy_graph (previously obs.as_networkx()) method:
  almost all powerlines attributes can now be read from the
  resulting graph object.
• possibility to set data_feeding_kwargs from the config file directly.
• so "FutureWarnings" are silenced (depending on pandas and pandapower version)
• error messages when "env.reset()" has not been called and some functions are not available.
• act.remove_line_status_from_topo can now be used without an observation and will "remove"
  all the impact on line status from the topology if it causes "AmbiguousAction" (this includes removing
  set_bus to 1 or 2 with set_line_status is -1 or to remove set_bus to -1 when set_line_status is 1
  or to remove change_bus when set_line_status is -1)
• possibility, for BackendConverter to converter between backends where one does support
  storage units (the one making powerflow) and the other one don't (the one the user will see).
• in BackendConverter names of the "source backend" can be used to match the time series data
  when the "use_target_backend_name=True" (new kwargs)
• environment do not crash when it fails to load redispatching data. It issues a warning and continue as if
  the description file was not present.
• BackendConverter is now able to automatically map between different backend with different naming convention
  under some hypothesis. CAREFUL: the generated mapping might not be the one you "have in mind" ! As for everything automatic,
  it's good because it's fast. It's terrible when you think it does something but in fact it does something else.
• the obs.get_energy_graph (previously obs.as_networkx()) method with added attributes for edges (origin and extremity substation, as well as origin and
  extremity buses)
• the doc of the obs.get_energy_graph (previously obs.as_networkx())
• it is now possible to use a different backend, a different grid or different kwargs between the
  env backend and the obs backend.
• the environment now called the "chronics_handler.forecast" function at most once per step.
• make it easier to create an environment without MultiFolder or MultifolderWithCache
• add the possibility to forward kwargs to chronix2grid function when calling env.generate_data
• when calling env.generate_data an extra file (json) will be read to set default values
  passed to chronix2grid.add_data
• it is no more reasonably possible to misuse the MultifolderWithCache (for example by
  forgetting to reset() the cache): an error will be raised in case the proper function has not been called.
• possibility to pass game rules by instance of object and not by class.