add fix for when result count is zero

Author: ccoffrin

CHANGELOG.md

@@ -7,7 +7,8 @@ PowerModels.jl Change Log
 - Added iterative flow limit cut OPF solvers (#619)
 - Improved connected components computation time (#504)
 - Removed `Inf` bounds from variables (#630)
-- Removal of unused functions in `solution.jl`: `get_solution`, `add_generator_power_setpoint`, `add_storage_setpoint`, `add_branch_flow_setpoint`, `add_dcline_flow_setpoint` (breaking) (#637) 
+- Removal of unused functions in `solution.jl`: `get_solution`, `add_generator_power_setpoint`, `add_storage_setpoint`, `add_branch_flow_setpoint`, `add_dcline_flow_setpoint` (breaking) (#637)
+- Fixed a solution reporting bug when the optimizer result count is zero
 
 ### v0.13.1
 - Added DCMPPowerModel for replication of Matpower's DC model (#612)

src/core/solution.jl

@@ -1,35 +1,53 @@
 ""
 function build_solution(pm::AbstractPowerModel, solve_time; solution_builder=solution_opf!)
-    # TODO @assert that the model is solved
-
     sol = _init_solution(pm)
-    data = Dict{String,Any}("name" => pm.data["name"])
 
+    # TODO replace with JuMP.result_count(pm.model) after version v0.21
+    # try-catch is needed until solvers reliably support ResultCount()
+    result_count = 1
+    try
+        result_count = _MOI.get(pm.model, _MOI.ResultCount())
+    catch
+        Memento.warn(_LOGGER, "the given optimizer does not provide the ResultCount() attribute, assuming the solver returned a solution which may be incorrect.");
+    end
+
+    if result_count > 0
+        if InfrastructureModels.ismultinetwork(pm.data)
+            sol["multinetwork"] = true
+            sol_nws = sol["nw"] = Dict{String,Any}()
+
+            for (n,nw_data) in pm.data["nw"]
+                sol_nw = sol_nws[n] = Dict{String,Any}()
+                sol_nw["baseMVA"] = nw_data["baseMVA"]
+                if haskey(nw_data, "conductors")
+                    sol_nw["conductors"] = nw_data["conductors"]
+                end
+                pm.cnw = parse(Int, n)
+                solution_builder(pm, sol_nw)
+            end
+        else
+            sol["baseMVA"] = pm.data["baseMVA"]
+            if haskey(pm.data, "conductors")
+                sol["conductors"] = pm.data["conductors"]
+            end
+            solution_builder(pm, sol)
+        end
+    else
+        Memento.warn(_LOGGER, "model has no results, solution cannot be built")
+    end
+
+    data = Dict{String,Any}("name" => pm.data["name"])
     if InfrastructureModels.ismultinetwork(pm.data)
-        sol["multinetwork"] = true
-        sol_nws = sol["nw"] = Dict{String,Any}()
         data_nws = data["nw"] = Dict{String,Any}()
 
         for (n,nw_data) in pm.data["nw"]
-            sol_nw = sol_nws[n] = Dict{String,Any}()
-            sol_nw["baseMVA"] = nw_data["baseMVA"]
-            if haskey(nw_data, "conductors")
-                sol_nw["conductors"] = nw_data["conductors"]
-            end
-            pm.cnw = parse(Int, n)
-            solution_builder(pm, sol_nw)
             data_nws[n] = Dict(
                 "name" => get(nw_data, "name", "anonymous"),
                 "bus_count" => length(nw_data["bus"]),
                 "branch_count" => length(nw_data["branch"])
             )
         end
     else
-        sol["baseMVA"] = pm.data["baseMVA"]
-        if haskey(pm.data, "conductors")
-            sol["conductors"] = pm.data["conductors"]
-        end
-        solution_builder(pm, sol)
         data["bus_count"] = length(pm.data["bus"])
         data["branch_count"] = length(pm.data["branch"])
     end

test/output.jl

@@ -20,6 +20,28 @@
         @test length(result["solution"]["bus"]) == 24
         @test length(result["solution"]["gen"]) == 33
     end
+
+    @testset "infeasible case" begin
+        # make sure code does not crash when ResultCount == 0
+        # change objective to linear so the case can load into cbc
+        data = parse_file("../test/data/matpower/case24.m")
+        for (i,gen) in data["gen"]
+            if gen["ncost"] > 2
+                gen["ncost"] = 2
+                gen["cost"] = gen["cost"][length(gen["cost"])-1:end]
+            end
+        end
+        result = run_opf(data, DCPPowerModel, cbc_solver)
+
+        @test haskey(result, "optimizer")
+        @test haskey(result, "termination_status")
+        @test haskey(result, "primal_status")
+        @test haskey(result, "dual_status")
+        @test haskey(result, "solve_time")
+        @test haskey(result, "solution")
+        @test !isnan(result["solve_time"])
+        @test length(result["solution"]) == 1
+    end
 end
 
 @testset "test branch flow output" begin