laser.cohorts.SIS
SIS model component preset.
Assembles the Susceptible and Infectious (recovery returns to S) compartments with SI-style transmission for use as a standalone SIS model.
Infectious(model, r_recovery=None, validating=False)
Bases: Infectious
Infectious (I) compartment with recovery back to S.
Extends Infectious by drawing newly recovered-susceptible individuals
each tick and moving them from I to S. Used in SIS model configurations
where immunity is not retained after infection.
Initialize the InfectiousToSusceptible component.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
model
|
Model
|
The parent model instance. |
required |
r_recovery
|
ValuesMap | None
|
Per-tick, per-node rate of recovery to S (I → S). Defaults to zero if not provided. |
None
|
validating
|
bool
|
Enable validation checks during simulation. |
False
|
property
properties
Return node properties required by this component.
Returns:
| Type | Description |
|---|---|
list[PropertyType]
|
list[PropertyType]: Parent properties plus
|
property
states
Return the compartment state names managed by this component.
Returns:
| Type | Description |
|---|---|
list[str]
|
list[str]: Parent states plus |
step(tick)
Apply I → S recovery to infectious individuals.
Draws newly susceptible individuals from a binomial using r_recovery,
moving them from I to S and recording the flow in nodes.newly_susceptible.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
tick
|
int
|
Current simulation tick (0-indexed). |
required |
Susceptible(model, validating=False)
Susceptible (S) compartment component.
Tracks the susceptible population and applies non-disease mortality each time step. Initial S counts are read from the scenario at setup.
Initialize the Susceptible component.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
model
|
Model
|
The parent model instance. |
required |
validating
|
bool
|
Enable validation checks during simulation. |
False
|
property
properties
Return node properties required by this component.
Returns:
| Type | Description |
|---|---|
list[PropertyType]
|
list[PropertyType]: Empty list; mortality tracking belongs to
|
property
states
Return the compartment state names managed by this component.
Returns:
| Type | Description |
|---|---|
list[str]
|
list[str]: |
end_step(tick)
No-op end-of-step hook for the S compartment.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
tick
|
int
|
Current simulation tick (0-indexed). |
required |
setup()
Initialize state S at tick 0 from the scenario S column.
start_step(tick)
No-op start-of-step hook; carry-forward is handled by the Model.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
tick
|
int
|
Current simulation tick (0-indexed). |
required |
step(tick)
No-op step hook for the S compartment.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
tick
|
int
|
Current simulation tick (0-indexed). |
required |
Transmission(
model, beta, seasonality=None, validating=False
)
Bases: TransmissionCommon
Transmission component that moves individuals directly from S to I.
Specialises TransmissionCommon for models without an exposed period (SI,
SIR, SIS, SIRS). Newly infected individuals enter the I compartment
immediately.
Initialize the S → I transmission component.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
model
|
Model
|
The parent model instance. |
required |
beta
|
ValuesMap
|
Per-tick, per-node transmission rate. |
required |
validating
|
bool
|
Enable validation checks during simulation. |
False
|
property
properties
Return node properties required by this component.
Returns:
| Type | Description |
|---|---|
list[PropertyType]
|
list[PropertyType]: Parent properties plus
|
property
states
Return the compartment state names managed by this component.
Returns:
| Type | Description |
|---|---|
list[str]
|
list[str]: Parent states plus |