Fix bound calculation for zero functions + Add tests

src/library/function/abstract.jl

@@ -83,11 +83,11 @@ function mingap(f::F; tol::T = 1E-6) where {V,T,F<:AbstractPBF{V,T}}
 end
 
 function lowerbound(f::F) where {V,T,F<:AbstractPBF{V,T}}
-    return sum((c < zero(T) || isempty(ω)) ? c : zero(T) for (ω, c) in f)
+    return sum((c < zero(T) || isempty(ω)) ? c : zero(T) for (ω, c) in f; init = zero(T))
 end
 
 function upperbound(f::F) where {V,T,F<:AbstractPBF{V,T}}
-    return sum((c > zero(T) || isempty(ω)) ? c : zero(T) for (ω, c) in f)
+    return sum((c > zero(T) || isempty(ω)) ? c : zero(T) for (ω, c) in f; init = zero(T))
 end
 
 function Base.convert(::Type{U}, f::AbstractPBF{V,T}) where {V,T,U<:Number}

test/unit/bounds.jl

@@ -0,0 +1,17 @@
+function test_bounds()
+    @testset "Bounds" begin
+        let f = PBO.PBF{Symbol,Float64}(:x => 1.0, :y => -1.0)
+            @test PBO.lowerbound(f) ≈ -1.0
+            @test PBO.upperbound(f) ≈  1.0
+            @test all(PBO.bounds(f) .≈ (-1.0, 1.0))
+        end
+
+        let f = zero(PBO.PBF{Symbol,Float64})
+            @test PBO.lowerbound(f) ≈ 0.0
+            @test PBO.upperbound(f) ≈ 0.0
+            @test all(PBO.bounds(f) .≈ (0.0, 0.0))
+        end
+    end
+
+    return nothing
+end

test/unit/unit.jl

@@ -3,6 +3,7 @@ include("term_parser.jl")
 include("constructors.jl")
 include("operators.jl")
 include("calculus.jl")
+include("bounds.jl")
 # include("discretization.jl")
 include("quadratization.jl")
 include("print.jl")
@@ -14,6 +15,7 @@ function unit_tests()
         test_constructors()
         test_operators()
         test_calculus()
+        test_bounds()
         # test_discretization()
         test_quadratization()
         test_print()