Does calculation methods in frontend.api implicitly define constraints?

[simplexity-ckcclc]

The calculation methods in frontend.api, like Add and Mul, do they implicitly enforce constraints to the variables? For example, sum := api.Add(c.A, c.B), can we say that it implicitly define a constraint: A + B = sum?

[ivokub]

The calculation methods in frontend.api, like Add and Mul, do they implicitly enforce constraints to the variables? For example, sum := api.Add(c.A, c.B), can we say that it implicitly define a constraint: A + B = sum?

In general yes, the calculations imply constraints. There are some edge cases though where we have optimized not to add constraints, e.g.

• double constraints - if there already exists similar (or a multiple of it) constraint for the inputs
• constant inputs - you can call for example sum := api.Add(2,1), in this case sum would be constant 3 and no constraint added
• trivial constraints - for example diff := api.Sub(x,x) is a constant 1 and no constraint is added.

And in some cases we add several constraints, depending on the complexity of computation. For example for api.Div imo we add several.