implement sethrep for interval (JuliaPolyhedra#267)

* implement sethrep for interval

* tests added and corrrection

src/interval.jl

@@ -35,7 +35,7 @@ surface(::Interval{T}) where {T} = zero(T)
 volume(p::Interval) = p.length
 Base.isempty(p::Interval) = isempty(p.vrep)
 
-function Interval{T, AT, D}(haslb::Bool, lb::T, hasub::Bool, ub::T, isempty::Bool) where {T, AT, D}
+function _interval(AT, haslb::Bool, lb::T, hasub::Bool, ub::T, isempty::Bool) where {T}
  if haslb && hasub && _gt(lb, ub)
  isempty = true
  end
@@ -77,10 +77,14 @@ function Interval{T, AT, D}(haslb::Bool, lb::T, hasub::Bool, ub::T, isempty::Boo
  h = hrep(hps, hss)
  v = vrep(ps, ls, rs)
  volume = isempty ? zero(T) : (haslb && hasub ? max(zero(T), ub - lb) : -one(T))
- Interval{T, AT, D}(h, v, volume)
+ return h, v, volume
 end
 
-function _hinterval(rep::HRep{T}, ::Type{AT}, D) where {T, AT}
+function Interval{T, AT, D}(haslb::Bool, lb::T, hasub::Bool, ub::T, isempty::Bool) where {T, AT, D}
+ return Interval{T, AT, D}(_interval(AT, haslb, lb, hasub, ub, isempty)...)
+end
+
+function _hinterval(rep::HRep{T}, ::Type{AT}) where {T, AT}
  haslb = false
  lb = zero(T)
  hasub = false
@@ -125,7 +129,11 @@ function _hinterval(rep::HRep{T}, ::Type{AT}, D) where {T, AT}
  _setub(hs.β / α)
  end
  end
- Interval{T, AT, D}(haslb, lb, hasub, ub, empty)
+ return _interval(AT, haslb, lb, hasub, ub, empty)
+end
+
+function _hinterval(rep::HRep{T}, ::Type{AT}, D) where {T, AT}
+ return Interval{T, AT, D}(_hinterval(rep, AT)...)
 end
 
 function _vinterval(v::VRep{T}, ::Type{AT}, D) where {T, AT}
@@ -191,3 +199,11 @@ function detecthlinearity!(::Interval) end
 function detectvlinearity!(::Interval) end
 function removehredundancy!(::Interval) end
 function removevredundancy!(::Interval) end
+
+function sethrep!(p::Interval{T, AT}, h::HRep) where {T, AT}
+ hnew, v, volume = _hinterval(h, AT)
+ p.hrep = hnew
+ p.vrep = v
+ p.length = volume
+ return p
+end 

test/interval.jl

@@ -9,6 +9,24 @@ function cartesian_product_test()
  inequality_fulltest(p, expected)
 end
 
+function sethrep_test()
+ # x_1 ≤ 2 x_1 ≥ -1 <=> -x_1 ≤ 1
+ h1 = HalfSpace([1], 2) ∩ HalfSpace([-1], 1)
+ v1 = convexhull([-1], [2])
+ p = polyhedron(h1)
+ @test volume(p) == 3
+ inequality_fulltest(p, h1)
+ generator_fulltest(p, v1)
+ # x_1 ≤ 1 x_1 ≥ -1 <=> -x_1 ≤ 1
+ h2 = HalfSpace([1], 1) ∩ HalfSpace([-1], 1)
+ v2 = convexhull([-1], [1])
+ Polyhedra.sethrep!(p, h2)
+ # Test that the three fields have been modified
+ @test volume(p) == 2
+ inequality_fulltest(p, h2)
+ generator_fulltest(p, v2)
+end
+
 @testset "Interval tests" begin
 
  # Closed interval
@@ -206,4 +224,8 @@ end
  @testset "Cartesian product (#132)" begin
  cartesian_product_test()
  end
+
+ @testset "sethrep! (#267)" begin
+ sethrep_test()
+ end
 end