Merge pull request #34 from rdeits/fix-extra-vars

fix warmstart!() introducing new variables
rdeits · Oct 11, 2017 · e7e4a4d · e7e4a4d
2 parents 1314454 + f72f481
commit e7e4a4d
Show file tree

Hide file tree

Showing 2 changed files with 22 additions and 2 deletions.
diff --git a/src/ConditionalJuMP.jl b/src/ConditionalJuMP.jl
@@ -211,10 +211,14 @@ end
 
 newbinaryvar(m::Model, args...) = newbinaryvar(getindmap!(m), args...)
 
-function getindicator!(m::IndicatorMap, c::Conditional)
+function getindicator!(m::IndicatorMap, c::Conditional, can_create=true)
     if haskey(m.indicators, c)
         return m.indicators[c]
     else
+        if !can_create
+            @show c
+            error("Not allowed to create a new variable here. Something has gone wrong")
+        end
         z = newbinaryvar(m)
         implies!(m.model, z, c)
         m.indicators[c] = z
@@ -242,6 +246,7 @@ end
 function disjunction!(indmap::IndicatorMap, imps::NTuple{2, Implication})
     z = getindicator!(indmap, first(imps[1]))
     implies!(indmap.model, z, second(imps[1]))
+    indmap.indicators[first(imps[2])] = 1 - z
     implies!(indmap.model, 1 - z, first(imps[2]))
     implies!(indmap.model, 1 - z, second(imps[2]))
     push!(indmap.disjunctions, Implication[imps...])
@@ -389,7 +394,7 @@ function warmstart!(m::Model, fix=false)
                 for i in eachindex(violations)
                     imp = implications[i]
                     lhs, rhs = imp
-                    z = getindicator!(indmap, lhs)
+                    z = getindicator!(indmap, lhs, false)
                     satisfied = i == best_match
                     if fix
                         if !isfixed(z)

diff --git a/test/runtests.jl b/test/runtests.jl
@@ -458,6 +458,21 @@ end
         @test getvalue(x) ≈ [0.8, 0.6]
     end
 
+    @testset "test that warmstart does not introduce new variables" begin
+        m = Model(solver=CbcSolver())
+        @variable m -1 <= x <= 1
+        @disjunction m (x == 0.5) (x == -0.5)
+        @objective m Min x
+        @test length(m.colCat) == 2
+        warmstart!(m, false)
+        @test length(m.colCat) == 2
+        solve(m)
+        @test getvalue(x) ≈ -0.5
+        warmstart!(m, true)
+        @test length(m.colCat) == 2
+        solve(m)
+        @test getvalue(x) ≈ -0.5
+    end
 end
 
 @testset "examples" begin