Function neptune::circuit::mul_sum

pub fn mul_sum<CS: ConstraintSystem<E>, E: Engine>(
    cs: CS, 
    a: &AllocatedNum<E>, 
    b: &AllocatedNum<E>, 
    to_add: E::Fr
) -> Result<AllocatedNum<E>, SynthesisError> where
    CS: ConstraintSystem<E>, 

Calculates a * (b + to_add) — and enforces that constraint.