pub fn starting_digest() -> Self {
        SepticDigest(SepticCurve {
            x: SepticExtension::<F>::from_base_fn(|i| F::from_canonical_u32(DIGEST_SUM_START_X[i])),
            y: SepticExtension::<F>::from_base_fn(|i| F::from_canonical_u32(DIGEST_SUM_START_Y[i])),
        })
    }
The digest used for starting the accumulation of digests.
crates/stark/src/septic_digest.rs