[Needs MOI 0.9.21] AffExpr in ZeroOne does not work

[blegat]

julia> using JuMP

julia> model = Model()
A JuMP Model
Feasibility problem with:
Variables: 0
Model mode: AUTOMATIC
CachingOptimizer state: NO_OPTIMIZER
Solver name: No optimizer attached.

julia> @variable(model, x)
x

julia> @constraint(model, x + 1 in MOI.Integer())
ERROR: MethodError: no method matching shift_constant(::MathOptInterface.Integer, ::Float64)
Closest candidates are:
  shift_constant(::Union{EqualTo{T}, GreaterThan{T}, LessThan{T}}, ::T) where T at /home/blegat/.julia/packages/MathOptInterface/C3lip/src/Utilities/sets.jl:39
  shift_constant(::MathOptInterface.Interval, ::Any) at /home/blegat/.julia/packages/MathOptInterface/C3lip/src/Utilities/sets.jl:42
Stacktrace:
 [1] build_constraint(::Function, ::GenericAffExpr{Float64,VariableRef}, ::MathOptInterface.Integer) at /home/blegat/.julia/packages/JuMP/jnmGG/src/macros.jl:491
 [2] top-level scope at /home/blegat/.julia/packages/JuMP/jnmGG/src/macros.jl:621

julia> @constraint(model, x + 1 in MOI.ZeroOne())
ERROR: MethodError: no method matching shift_constant(::MathOptInterface.ZeroOne, ::Float64)
Closest candidates are:
  shift_constant(::Union{EqualTo{T}, GreaterThan{T}, LessThan{T}}, ::T) where T at /home/blegat/.julia/packages/MathOptInterface/C3lip/src/Utilities/sets.jl:39
  shift_constant(::MathOptInterface.Interval, ::Any) at /home/blegat/.julia/packages/MathOptInterface/C3lip/src/Utilities/sets.jl:42
Stacktrace:
 [1] build_constraint(::Function, ::GenericAffExpr{Float64,VariableRef}, ::MathOptInterface.ZeroOne) at /home/blegat/.julia/packages/JuMP/jnmGG/src/macros.jl:491
 [2] top-level scope at /home/blegat/.julia/packages/JuMP/jnmGG/src/macros.jl:621

We should probably leave the constant in the function for these sets.

Reported by @jebouchat

[1ozturkbe]

This issue has been a real difficulty in JuMP/MOI for me, using the latest versions (0.21.3 and 0.9.14). I would like to be able to constrain variables to integer or binary post-declaration, eg:

using JuMP, MathOptInterface
m = Model()
@variable(m, x[1:3])
@constraint(m, x[1] in MathOptInterface.Integer())

I get an error in constructconstraint!.

ERROR: MethodError: no method matching constructconstraint!(::JuMP.GenericAffExpr{Float64,Variable}, ::MathOptInterface.Integer)
Closest candidates are:
  constructconstraint!(::JuMP.GenericAffExpr{Float64,Variable}, ::Any, ::Any) at 
...

I'm assuming these issues are related, since I tried the above example and got the same result. I work around right now as such, but I'd prefer not doubling up on variables.

    aux = @variable(m, [1:length(int_idxs)], Int);
    @constraint(m, x[int_idxs] .== aux);

Thanks for the help.

[mlubin]

@1ozturkbe

I would like to be able to constrain variables to integer or binary post-declaration

Use set_integer or set_binary.

[odow]

I have a plan for this, but it requires: jump-dev/MathOptInterface.jl#1237. It has the added benefit of making it much more explicit when JuMP will push the function into the set.

[odow]

Accidentally closed by the MOI PR.

[odow]

MOI now has supports_shift_constant.

[blegat]

Wy don't we leave the constant in the functio' instead or returning an error? Then it can be bridged with a slack bridge

[odow]

That's what we do

[odow]

https://github.com/jump-dev/JuMP.jl/pull/2705/files#diff-e628f2d30670b1af0cdd9c9c520aaddc44021cd503e169d767ec49c95f189264R490-R497

[blegat]

I missread the PR diff