Observation space

As introduced in Section Decision problems, gym-DSSAT problems are POMDPs. In Section Observation spaces, we shortly showed the successive subsets of DSSAT’s internal variables to define the observations provided to the agent. By modifying the list of variables constituting the observations, you can modulate “the degree of partial observability” of the POMDP.

The observation space can be customized by simply editing the gym environment’s yaml configuration file. For instance after package installation, you can simply edit:

${GYM_DSSAT_PDI_PATH}/envs/configs/env_config.yml

If we take the example of a new foo fertilization problem, we can define it following:

#################
# RAW STATE SPACE
#################
state: # <- list of all DSSAT's internal features made available in gym-DSSAT
# please keep it untouched !
   vstage:
      type: float
      low: 0
      high: .inf
      info: vegetative growth stage (number of leaves)
   cleach:
      type: float
      low: 0
      high: .inf
      info: cumulative nitrate leaching (kg/ha)
   dtt:
      type: float
      low: 0
      high: 100
      info: growing degree days for current day (C/d)
   dul:
      type: array
      subtype: float
      low: 0
      high: 1
      size: 9
      info: volumetric soil water content in soil layers at drained upper limit (cm3 [water] / cm3 [soil])
   xlai:
      type: float
      low: 0
      high: .inf
      info: plant population leaf area index (m2_leaf/m2_soil)
   ...

#######################################################
# ACTION AND STATE SPACES RESTRICTIONS FOR ENV SETTINGS
#######################################################
setting:
   foo:  # <- the new setting
      action:
         - anfer
      state:
         - cleach
         - dtt
         - vstage
      context:  # additional contextual information ; corresponds to gym's "info".
         - dul
      experiment_number: 1  # number of the experiment in DSSAT's fileX.

Warning

You cannot import new state features from DSSAT-PDI by simply adding variables to the state YAML key of the raw state space without modifying more deeply DSSAT-pdi. For the straighforward way, you can only modify the state key inside the setting key, for the considered setting as shown above.

Note

For understanding what DSSAT’s fileX is, please check DSSAT’s user guide.