Function increment_y_values 

pub fn increment_y_values<'a, K: Field + From<F> + Add<F, Output = K> + Sub<F, Output = K> + Mul<F, Output = K>, F: Field, EF: ExtensionField<F> + From<K> + AbstractExtensionField<K>, A: for<'b> Air<ConstraintSumcheckFolder<'b, F, K, EF>> + MachineAir<F>, const IS_FIRST_ROUND: bool>(
    public_values: &[F],
    powers_of_alpha: &[EF],
    air: &A,
    y_0: &mut EF,
    y_2: &mut EF,
    y_4: &mut EF,
    preprocessed_column_vals_0: &[K],
    main_column_vals_0: &[K],
    preprocessed_column_vals_2: &[K],
    main_column_vals_2: &[K],
    preprocessed_column_vals_4: &[K],
    main_column_vals_4: &[K],
    interaction_batching_powers: &[EF],
    eq: EF,
)

This function will increment the y0, y2, and y4 accumulators by the eval of the constraint polynomial at the points 0, 2, and 4.