Struct CSM 

pub struct CSM<I, O, C>
where
    I: Default + Clone,
    O: CsmEvaluable + Default + Debug + Clone,
    C: Clone,
{ /* private fields */ }

Causal State Machine (CSM)

A Causal State Machine (CSM) is a structure that manages relationships between causal states and actions. It provides a mechanism for evaluating states based on input data and triggering associated actions when specific conditions are met.

Purpose

The CSM is designed to model systems where different states can trigger specific actions when certain conditions are met. It’s particularly useful for:

• Event-driven systems where actions should be triggered based on state changes
• Monitoring systems that need to respond to specific conditions
• Control systems that need to take actions based on sensor readings
• Any system where cause-effect relationships need to be modeled and evaluated

How It Works

1. The CSM maintains a collection of causal states paired with actions
2. Each causal state contains a causaloid that defines when the state should trigger its action
3. When data is fed into the CSM, it evaluates the relevant states
4. If a state’s conditions are met (evaluated to true), the associated action is triggered

Usage

The CSM is typically used by:

1. Creating causal states with appropriate causaloids that define trigger conditions
2. Creating actions that should be executed when states are triggered
3. Initializing a CSM with state-action pairs
4. Feeding data into the CSM for evaluation

See the example in examples/csm/src/main.rs for a practical implementation.

Implementations

impl<I, O, C> CSM<I, O, C>

where I: Default + Clone + Debug + Send + Sync + 'static, O: CsmEvaluable + Default + Debug + Clone + Send + Sync + 'static, C: Clone + Debug + Send + Sync + 'static,

pub fn eval_single_state( &self, id: usize, data: &PropagatingEffect<I>, ) -> Result<(), CsmError>

Evaluates a single causal state at the index position id. If the state evaluates to an active effect, the associated action is fired. An active effect can be Deterministic(true) or an Uncertain type that passes its hypothesis test.

Errors

Returns CsmError if the state does not exist, evaluation fails, or the action fails to fire. Also returns an error if the causaloid returns a probabilistic effect, which cannot be evaluated in a single state context.

pub fn eval_all_states(&self) -> Result<(), CsmError>

Evaluates all causal states in the CSM using their internal data. For each state that evaluates to an active effect, the associated action is fired.

Errors

Returns CsmError if any state evaluation or action firing fails.

impl<I, O, C> CSM<I, O, C>

where I: Default + Clone, O: CsmEvaluable + Default + Debug + Clone, C: Clone,

pub fn add_single_state( &self, state_action: StateAction<I, O, C>, ) -> Result<(), UpdateError>

Inserts a new state action using the state’s internal ID. Returns UpdateError if a state with that ID already exists.

impl<I, O, C> CSM<I, O, C>

where I: Default + Clone, O: CsmEvaluable + Default + Debug + Clone, C: Clone,

pub fn remove_single_state(&self, id: usize) -> Result<(), UpdateError>

Removes a state action at the index position id. Returns UpdateError if the index does not exist.

impl<I, O, C> CSM<I, O, C>

where I: Default + Clone, O: CsmEvaluable + Default + Debug + Clone, C: Clone,

pub fn update_single_state( &self, state_action: StateAction<I, O, C>, ) -> Result<(), UpdateError>

Updates a causal state using the state’s internal ID. Returns UpdateError if the state does not exist.

pub fn update_all_states( &self, state_actions: &[(&CausalState<I, O, C>, &CausalAction)], ) -> Result<(), UpdateError>

Updates all causal state with a new state collection. Note, this operation erases all previous states in the CSM by generating a new collection. Returns UpdateError if the update operation failed.

impl<I, O, C> CSM<I, O, C>

where I: Default + Clone, O: CsmEvaluable + Default + Debug + Clone, C: Clone,

pub fn new(state_actions: &[(&CausalState<I, O, C>, &CausalAction)]) -> Self

Constructs a new CSM.

pub fn len(&self) -> usize

Returns the number of elements in the CSM.

pub fn is_empty(&self) -> bool

Returns true if the CSM contains no elements.