Fix bug in Chalmet (#117)

Author: odow

src/algorithms/Chalmet.jl

@@ -89,7 +89,7 @@ function optimize_multiobjective!(algorithm::Chalmet, model::Optimizer)
     end
     _, y2[1] = _compute_point(model, variables, f1)
     if y2[1] ≈ solutions[1].y[1]
-        return MOI.OPTIMAL, [solutions]
+        return MOI.OPTIMAL, solutions
     end
     MOI.set(model.inner, MOI.ObjectiveFunction{typeof(f2)}(), f2)
     y2_constraint = MOI.Utilities.normalize_and_add_constraint(

test/algorithms/Chalmet.jl

@@ -218,6 +218,23 @@ function test_too_many_objectives()
     return
 end
 
+function test_single_point()
+    model = MOA.Optimizer(HiGHS.Optimizer)
+    MOI.set(model, MOA.Algorithm(), MOA.Chalmet())
+    MOI.set(model, MOI.Silent(), true)
+    x = MOI.add_variables(model, 2)
+    MOI.add_constraint.(model, x, MOI.EqualTo(1.0))
+    MOI.set(model, MOI.ObjectiveSense(), MOI.MIN_SENSE)
+    f = MOI.Utilities.operate(vcat, Float64, 1.0 .* x...)
+    MOI.set(model, MOI.ObjectiveFunction{typeof(f)}(), f)
+    MOI.optimize!(model)
+    @test MOI.get(model, MOI.TerminationStatus()) == MOI.OPTIMAL
+    @test MOI.get(model, MOI.ResultCount()) == 1
+    @test MOI.get(model, MOI.PrimalStatus()) == MOI.FEASIBLE_POINT
+    @test ≈(MOI.get(model, MOI.VariablePrimal(), x), [1.0, 1.0]; atol = 1e-6)
+    return
+end
+
 end  # module TestChalmet
 
 TestChalmet.run_tests()