Function generate_caption 

pub fn generate_caption<R: Rng>(
    x_norm: &ArrayView2<'_, f64>,
    mask: Option<&Array2<u8>>,
    ctx: &CaptionContext,
    key: CaptionKey,
    rng: &mut R,
) -> Result<String>

Generate the caption text for the requested CaptionKey.

Arguments

• x_norm – Z-score normalised sensor tensor, shape (1440, C).
• mask – Optional missingness mask (1 = imputed), same shape as x_norm.
• ctx – Semantic context (activities, sleep, moods).
• key – Which caption variant to produce.
• rng – Random number generator for template selection.