Allow Constraint to convert Ints into Float64 in the bounds

docs/src/metabolic-modeling.jl

@@ -280,8 +280,8 @@ C.constraint_values(c.objective, optimal_variable_assignment)
 # organisms:
 c =
     :community^(
-        :species1^(c * :handicap^C.Constraint(c.fluxes.R_PFK.value, 0.0)) +
-        :species2^(c * :handicap^C.Constraint(c.fluxes.R_ACALD.value, 0.0))
+        :species1^(c * :handicap^C.Constraint(c.fluxes.R_PFK.value, 0)) +
+        :species2^(c * :handicap^C.Constraint(c.fluxes.R_ACALD.value, 0))
     )
 
 # We can create additional variables that represent total community intake of
@@ -349,10 +349,10 @@ Dict(k => v.fluxes.R_BIOMASS_Ecoli_core_w_GAM for (k, v) in result.community)
 c.exchanges.oxygen.bound = (-20.0, 20.0)
 
 # ...or rebuild a whole constraint:
-c.exchanges.biomass = C.Constraint(c.exchanges.biomass.value, (-20.0, 20.0))
+c.exchanges.biomass = C.Constraint(c.exchanges.biomass.value, (-20, 20))
 
 # ...or even add new constraints, here using the index syntax for demonstration:
-c[:exchanges][:production_is_zero] = C.Constraint(c.exchanges.biomass.value, 0.0)
+c[:exchanges][:production_is_zero] = C.Constraint(c.exchanges.biomass.value, 0)
 
 # ...or remove some constraints (this erases the constraint that was added just
 # above):

docs/src/quadratic-optimization.jl

@@ -32,7 +32,7 @@ error_val =
 
 # This allows us to naturally express quadratic constraint (e.g., that an error
 # must not be too big); and directly observe the error values in the system.
-system = :vars^system * :error^C.Constraint(value = error_val, bound = (0.0, 100.0))
+system = :vars^system * :error^C.Constraint(error_val, (0, 100))
 
 # (For simplicity, you can also use the `Constraint` constructor to make
 # quadratic constraints out of `QuadraticValue`s -- it will overload properly.)

src/constraint.jl

@@ -26,6 +26,10 @@ Base.@kwdef mutable struct Constraint{V}
     end
 end
 
+Constraint(v::T, b::Int) where {T<:Value} = Constraint(v, Float64(b))
+Constraint(v::T, b::Tuple{X,Y}) where {T<:Value,X<:Real,Y<:Real} =
+    Constraint(v, Float64.(b))
+
 Base.:-(a::Constraint) = -1 * a
 Base.:*(a::Real, b::Constraint) = b * a
 Base.:*(a::Constraint, b::Real) = Constraint(