✨ Add vcat for SingleVariable and VectorOfVariables

src/Bridges/Constraint/geomean.jl

@@ -59,7 +59,8 @@ function bridge_constraint(::Type{GeoMeanBridge{T, F, G}}, model,
 
     xl1 = MOI.SingleVariable(xij[1])
     sN = one(T) / √N
-    function _getx(i)
+    A = MOIU.promote_operation(*, T, T, MOI.SingleVariable)
+    function _getx(i)::A
         if i > n
             return sN * xl1
         else
@@ -69,10 +70,9 @@ function bridge_constraint(::Type{GeoMeanBridge{T, F, G}}, model,
 
     t = f_scalars[1]
     # With sqrt(2)^l*t - xl1, we should scale both the ConstraintPrimal and ConstraintDual
-    tubc = MOIU.add_scalar_constraint(model,
-                                      MOIU.operate!(+, T, t, -sN * xl1),
-                                      MOI.LessThan(zero(T)),
-                                      allow_modify_function=true)
+    tubc = MOIU.add_scalar_constraint(
+        model, MOIU.operate!(+, T, t, -sN * xl1), MOI.LessThan(zero(T)),
+        allow_modify_function=true)
 
     socrc = Vector{CI{G, MOI.RotatedSecondOrderCone}}(undef, N-1)
     offset = offsetnext = 0
@@ -83,13 +83,13 @@ function bridge_constraint(::Type{GeoMeanBridge{T, F, G}}, model,
                 a = _getx(2j-1)
                 b = _getx(2j)
             else
-                a = one(T) * MOI.SingleVariable(xij[offsetnext+2j-1])
-                b = one(T) * MOI.SingleVariable(xij[offsetnext+2j])
+                a = convert(A, MOI.SingleVariable(xij[offsetnext+2j-1]))
+                b = convert(A, MOI.SingleVariable(xij[offsetnext+2j]))
             end
             c = MOI.SingleVariable(xij[offset+j])
-            socrc[offset + j] = MOI.add_constraint(model,
-                                                   MOIU.operate(vcat, T, a, b, c),
-                                                   MOI.RotatedSecondOrderCone(3))
+            socrc[offset + j] = MOI.add_constraint(
+                model, MOIU.operate(vcat, T, a, b, c),
+                MOI.RotatedSecondOrderCone(3))
         end
         offset = offsetnext
     end

src/Utilities/functions.jl

@@ -1334,6 +1334,30 @@ function fill_vector(vector::Vector, ::Type{T}, vector_offset::Int,
                 funcs...)
 end
 
+function fill_variables(variables::Vector{MOI.VariableIndex}, offset::Int,
+                        output_offset::Int, func::MOI.SingleVariable)
+    variables[offset + 1] = func.variable
+end
+
+function fill_variables(variables::Vector{MOI.VariableIndex}, offset::Int,
+                        output_offset::Int, func::MOI.VectorOfVariables)
+    variables[offset .+ (1:length(func.variables))] .= func.variables
+end
+
+function promote_operation(::typeof(vcat), ::Type{T},
+                           ::Type{<:Union{MOI.SingleVariable,
+                                          MOI.VectorOfVariables}}...) where T
+    return MOI.VectorOfVariables
+end
+function operate(::typeof(vcat), ::Type{T},
+                 funcs::Union{MOI.SingleVariable,
+                              MOI.VectorOfVariables}...) where T
+    out_dim = sum(func -> output_dim(T, func), funcs)
+    variables = Vector{MOI.VariableIndex}(undef, out_dim)
+    fill_vector(variables, T, 0, 0, fill_variables, output_dim, funcs...)
+    return MOI.VectorOfVariables(variables)
+end
+
 number_of_affine_terms(::Type{T}, ::T) where T = 0
 number_of_affine_terms(::Type, ::SVF) = 1
 number_of_affine_terms(::Type, f::VVF) = length(f.variables)

test/Bridges/Constraint/geomean.jl

@@ -1,3 +1,16 @@
+using Test
+
+using MathOptInterface
+const MOI = MathOptInterface
+const MOIT = MathOptInterface.Test
+const MOIU = MathOptInterface.Utilities
+const MOIB = MathOptInterface.Bridges
+
+include("../utilities.jl")
+
+mock = MOIU.MockOptimizer(MOIU.Model{Float64}())
+config = MOIT.TestConfig()
+
 @testset "GeoMean" begin
     mock.optimize! = (mock::MOIU.MockOptimizer) -> MOIU.mock_optimize!(mock, [ones(4); 2; √2; √2])
     bridged_mock = MOIB.Constraint.GeoMean{Float64}(mock)

test/Utilities/functions.jl

@@ -22,8 +22,16 @@ z = MOI.VariableIndex(3)
         v = MOI.VectorOfVariables([y, w])
         wf = MOI.SingleVariable(w)
         xf = MOI.SingleVariable(x)
-        @testset "Variable" begin
-            # TODO #616
+        @testset "Variable with $T" for T in [Int, Float64]
+            @test MOI.VectorOfVariables == MOIU.promote_operation(vcat, T, typeof(wf), typeof(v), typeof(xf))
+            vov = MOIU.operate(vcat, T, wf, v, xf)
+            @test vov.variables == [w, y, w, x]
+            @test MOI.VectorOfVariables == MOIU.promote_operation(vcat, T, typeof(v), typeof(wf), typeof(xf))
+            vov = MOIU.operate(vcat, T, v, wf, xf)
+            @test vov.variables == [y, w, w, x]
+            @test MOI.VectorOfVariables == MOIU.promote_operation(vcat, T, typeof(wf), typeof(xf), typeof(v))
+            vov = MOIU.operate(vcat, T, wf, xf, v)
+            @test vov.variables == [w, x, y, w]
         end
         f = MOI.ScalarAffineFunction(
             MOI.ScalarAffineTerm.([2, 4], [x, z]), 5)