Function neptune::circuit::mul_sum

pub fn mul_sum<CS: ConstraintSystem<E>, E: Engine>(
    mut cs: CS, 
    a: &AllocatedNum<E>, 
    b: &AllocatedNum<E>, 
    pre_add: Option<E::Fr>, 
    post_add: Option<E::Fr>, 
    enforce: bool
) -> Result<AllocatedNum<E>, SynthesisError> where
    CS: ConstraintSystem<E>, 

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