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Modality

Student Assessment

StudentAssessment is the student-facing assessment modality. It manages the answer submission flow, tracks knowledge state, and uses the AlgorithmEngine for adaptive question selection.

Struct

Section titled “Struct”
pub struct StudentAssessment {
    state: State<StudentAssessmentSynced, StudentAssessmentEphemeral>,
    services: Arc<StudentAssessmentServices>,
    cmd_tx: CommandSender<...>,
    cmd_rx: CommandReceiver<...>,
}

The services include the AlgorithmEngine for adaptive question selection:

pub struct StudentAssessmentServices {
    pub agent: Arc<AgentService>,
    pub algorithm: AlgorithmEngine,
}

Synced State

Section titled “Synced State”
pub struct StudentAssessmentSynced {
    pub meta: ResourceMeta,
    pub session_id: String,
    pub student_id: String,
    pub placements: Vec<ComponentPlacement<QuestionSequencePosition>>,
    pub answers: HashMap<String, AnswerData>,
    pub knowledge_snapshot: Vec<(usize, f32)>,    // sparse knowledge vector
    pub indicator_snapshot: Vec<(usize, f32)>,     // sparse skill indicator
    pub status: StudentAssessmentStatus,
}

Ephemeral State

Section titled “Ephemeral State”
pub struct StudentAssessmentEphemeral {
    pub current_question_index: usize,
    pub precomputed_next: Option<PrecomputedBranch>,
    pub output: Vec<AssessmentElement>,
}

The precomputed_next field holds pre-calculated next questions for both correct and incorrect outcomes, enabling instant transitions.

Position

Section titled “Position”

QuestionSequencePosition describes a question’s place in the sequence:

pub struct QuestionSequencePosition {
    pub sequence_number: usize,
    pub question_id: String,
}

Status Lifecycle

Section titled “Status Lifecycle”
InProgress → Paused → InProgress
     |
     └→ Completed
StatusMeaning
InProgressStudent is actively answering questions
PausedStudent paused or teacher paused the session
CompletedAssessment finished (all questions answered or ended)

Intents

Section titled “Intents”
IntentParametersPurpose
Start—Begin the assessment, compute first question
SubmitAnsweranswer: StringSubmit answer for current question
SkipQuestion—Skip current question without answering
Pause—Pause the assessment
Resume—Resume from pause
End—End the assessment early
Recompile—Force recompilation (hidden)

Feedback

Section titled “Feedback”

Async operations produce feedback that arrives on the next dispatch cycle:

pub enum StudentAssessmentFeedback {
    PrecomputedBranch {
        if_correct: Option<String>,    // question ID if answer is correct
        if_incorrect: Option<String>,  // question ID if answer is incorrect
    },
    NextQuestionComputed {
        question_id: String,
    },
}

Answer Flow

Section titled “Answer Flow”
  1. Start — spawns async computation via AlgorithmEngine to select the first question
  2. NextQuestionComputed feedback — adds new placement to the sequence
  3. Precomputed branches — while student answers, the engine pre-computes what comes next for both outcomes
  4. SubmitAnswer — stores answer data, triggers knowledge update (direct + indirect), selects next question
  5. Knowledge update — direct impact on tested skills, indirect propagation via distance matrix, clipped to [KL, KU]

Knowledge Update Detail

Section titled “Knowledge Update Detail”

When an answer is submitted:

1. Direct knowledge = current + (±1 × score_factor × DIRECT_MULTIPLIER) per tested skill
2. Indirect knowledge = propagation along distance matrix edges to untested skills
3. Clip to [KL, KU] bounds
4. Store updated knowledge_snapshot (sparse)
5. Compute next question from updated state

Uses nalgebra::DVector internally for linear algebra operations.

Snapshot

Section titled “Snapshot”
pub struct StudentAssessmentSnapshot {
    pub id: String,
    pub name: String,
    pub session_id: String,
    pub student_id: String,
    pub placements: Vec<StudentQuestionPlacement>,
    pub answers: HashMap<String, AnswerData>,
    pub current_question_index: usize,
    pub status: StudentAssessmentStatus,
    pub version: u64,
    pub export_ready: bool,
}
Section titled “Related”