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Demands

Demand

Bases: BaseModel

Source code in passengersim/config/demands.py 
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class Demand(BaseModel, extra="forbid"):
    orig: str
    """Origin location for this demand.

    This is commonly a three letter airport code, but it need not be limited
    to airports.  It can be any location that is relevant to the simulation.

    If using 'places' for locations, this should match the 'name' field of
    a Place object."""

    dest: str
    """Destination location for this demand.

    This is commonly a three letter airport code, but it need not be limited
    to airports.  It can be any location that is relevant to the simulation.

    If using 'places' for locations, this should match the 'name' field of
    a Place object."""

    segment: str
    """Customer segment that this demand belongs to.

    For many applications, segments include 'business' and 'leisure', but
    they are not limited to these two categories."""

    @property
    def identifier(self):
        """Unique identifier for this demand."""
        return f"{self.orig}~{self.dest}@{self.segment}"

    base_demand: float
    reference_fare: float
    distance: float | None = 0.0
    choice_model: str | None = None
    """The name of the choice model that is applied for this demand."""

    todd_curve: str | None = None
    """Time Of Day curve to be used in the choice model.  These
       can vary by length of haul, day of week, E-W directionality, etc.
       If specified here, it will override the curve in the ChoiceModel"""

    curve: str | None = None
    """The name of the booking curve that is applied for this demand.

    Each demand is attached to a booking curve that describes the temporal
    distribution of customer arrivals."""

    group_sizes: list[float] | None = None
    """Probability of each group size.

    i.e. [0.5, 0.3, 0.2] will give 50% one pax, 30% 2 pax, etc"""

    prob_saturday_night: bool = False
    """Probability that the customer has a R/T itinerary with a Saturday night stay.
       Using this for choice modeling and CP experiments"""

    prob_num_days: list[float] = []
    """Probability of durations.
       [0.1, 0.3, 0.4, 0.2] will have durations of 1, 2, 3, 4 days
       and probability of each is specified explicitly
       Using this for choice modeling and CP experiments"""

    @property
    def choice_model_(self):
        """Choice model, falling back to segment name if not set explicitly."""
        return self.choice_model or self.segment

    @field_validator("curve", mode="before")
    def curve_integer_name(cls, v):
        """Booking curves can have integer names, treat as string."""
        if isinstance(v, int):
            v = str(v)
        return v

base_demand instance-attribute 

base_demand: float

choice_model class-attribute instance-attribute 

choice_model: str | None = None

The name of the choice model that is applied for this demand.

choice_model_ property 

choice_model_

Choice model, falling back to segment name if not set explicitly.

curve class-attribute instance-attribute 

curve: str | None = None

The name of the booking curve that is applied for this demand.

Each demand is attached to a booking curve that describes the temporal distribution of customer arrivals.

dest instance-attribute 

dest: str

Destination location for this demand.

This is commonly a three letter airport code, but it need not be limited to airports. It can be any location that is relevant to the simulation.

If using 'places' for locations, this should match the 'name' field of a Place object.

distance class-attribute instance-attribute 

distance: float | None = 0.0

group_sizes class-attribute instance-attribute 

group_sizes: list[float] | None = None

Probability of each group size.

i.e. [0.5, 0.3, 0.2] will give 50% one pax, 30% 2 pax, etc

identifier property 

identifier

Unique identifier for this demand.

orig instance-attribute 

orig: str

Origin location for this demand.

This is commonly a three letter airport code, but it need not be limited to airports. It can be any location that is relevant to the simulation.

If using 'places' for locations, this should match the 'name' field of a Place object.

prob_num_days class-attribute instance-attribute 

prob_num_days: list[float] = []

Probability of durations. [0.1, 0.3, 0.4, 0.2] will have durations of 1, 2, 3, 4 days and probability of each is specified explicitly Using this for choice modeling and CP experiments

prob_saturday_night class-attribute instance-attribute 

prob_saturday_night: bool = False

Probability that the customer has a R/T itinerary with a Saturday night stay. Using this for choice modeling and CP experiments

reference_fare instance-attribute 

reference_fare: float

segment instance-attribute 

segment: str

Customer segment that this demand belongs to.

For many applications, segments include 'business' and 'leisure', but they are not limited to these two categories.

todd_curve class-attribute instance-attribute 

todd_curve: str | None = None

Time Of Day curve to be used in the choice model. These can vary by length of haul, day of week, E-W directionality, etc. If specified here, it will override the curve in the ChoiceModel

curve_integer_name 

curve_integer_name(v)

Booking curves can have integer names, treat as string.

Source code in passengersim/config/demands.py 
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@field_validator("curve", mode="before")
def curve_integer_name(cls, v):
    """Booking curves can have integer names, treat as string."""
    if isinstance(v, int):
        v = str(v)
    return v