disallow automatic conversion from interval to float (#34)

Author: lucaferranti

docs/src/changelog.md

@@ -4,6 +4,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 ## Unreleased
 
+- ![](https://img.shields.io/badge/bugfix-purple.svg) disallow implicit conversion from interval to float
 - ![](https://img.shields.io/badge/new%20feature-green.svg) added semi-elliptic and singleton membership functions
 - ![](https://img.shields.io/badge/new%20feature-green.svg) added `gensurf` to plot generating surface
 - ![](https://img.shields.io/badge/bugfix-purple.svg) fix plotting of systems with several rules and membership functions.

src/evaluation.jl

@@ -46,8 +46,9 @@ end
 
 function (fis::SugenoFuzzySystem)(inputs::T) where {T <: NamedTuple}
     S = float(eltype(T))
-    res = Dictionary{Symbol, S}(keys(fis.outputs),
-                                zeros(float(eltype(T)), length(fis.outputs)))
+    res = Dictionary{Symbol, Union{S, Interval{S}}}(keys(fis.outputs),
+                                                    zeros(float(eltype(T)),
+                                                          length(fis.outputs)))
     weights_sum = zero(S)
     for rule in fis.rules
         w = scale(rule.antecedent(fis, inputs), rule)

src/intervals.jl

@@ -13,7 +13,6 @@ diam(a::Interval) = a.hi - a.lo
 diam(x::Real) = zero(x)
 
 Base.convert(::Type{Interval{T}}, x::Real) where {T <: Real} = Interval(T(x), T(x))
-Base.convert(::Type{T}, x::Interval) where {T <: AbstractFloat} = (x.lo + x.hi) / 2
 
 Base.float(::Type{Interval{T}}) where {T <: Real} = T
 

test/test_evaluation.jl

@@ -182,5 +182,5 @@ end
         service == good --> tip == average
         service == excellent || food == delicious --> tip == generous
     end
-    @test fis(service = 2, food = 3)[:tip]≈FuzzyLogic.Interval(5.304, 19.792) atol=1e-3
+    @test fis(service = 2, food = 3)[:tip]≈FuzzyLogic.Interval(2.94, 28.613) atol=1e-3
 end

test/test_intervals.jl

@@ -24,6 +24,5 @@ using FuzzyLogic: Interval, inf, sup, mid, diam
     @test zero(Interval{Float64}) == Interval(0.0, 0.0)
 
     @test convert(Interval{Float64}, 1.0) == Interval(1.0, 1.0)
-    @test convert(Float64, Interval(0.0, 1.0)) == 0.5
     @test float(Interval{BigFloat}) == BigFloat
 end