Fix sin, cos, periodise, symmetrise

Add tests

Author: dpsanders

src/transformations.jl

@@ -6,7 +6,12 @@ Return the integers enclosed in the interval `x`.
 """
 
 function integer_contractor(x::Interval)
-    a = floor(x.lo)+1
+
+    if isinteger(x.lo)
+        a = x.lo
+    else
+        a = floor(x.lo)+1
+    end
     b = floor(x.hi)
 
     a > b && return emptyinterval(x)
@@ -57,7 +62,7 @@ translate(C, α) = translate(-α) ∘ C ∘ translate(α)
 Symmetric part of a Contractor, via an involution `op`
 (i.e. such that `inv(op) == op`).
 """
-symmetrise(C, op) = op ∘ C ∘ op
+symmetrise(C, op) = X -> C(X) ∪ (op ∘ C ∘ op)(X)
 
 
 

src/trig.jl

@@ -24,6 +24,7 @@ function sin_main(X::IntervalBox)
 end
 
 # TODO: Be careful with the pi constants if using e.g. BigFloats
+sin_full = symmetrise(sin_main, reflect_x(half_pi))
 sin_reverse = symmetrise(sin_main, reflect_x(half_pi))
 
 """
@@ -33,7 +34,8 @@ Contractor for `sin`.
 Takes an `IntervalBox` containing the `x` and `y` component intervals.
 Returns an `IntervalBox` contracted down to the set ``y = \\sin(x)``.
 """
-sin!(X::IntervalBox) = periodise(sin_main, two_pi)(X) ∪ periodise(sin_reverse, two_pi)(X)
+sin!(X::IntervalBox) = #periodise(sin_main, two_pi)(X) ∪ periodise(sin_reverse, two_pi)(X)
+periodise(sin_full, two_pi)(X)
 
 # Reverse function for sin; does not alter y
 """
@@ -85,15 +87,17 @@ end
 # TODO: Be careful with the pi constants if using e.g. BigFloats
 cos_reverse = symmetrise(cos_main, reflect_x(0.0))
 
+cos_full = symmetrise(cos_main, reflect_x(0.0))
+
 """
     cos!(X::IntervalBox)
 
 Contractor for `cos`.
 Takes an `IntervalBox` containing the `x` and `y` component intervals.
 Returns an `IntervalBox` contracted down to the set ``y = \\cos(x)``.
 """
-cos!(X::IntervalBox) = periodise(cos_main, two_pi)(X) ∪ periodise(cos_reverse, two_pi)(X)
-
+cos!(X::IntervalBox) = #periodise(cos_main, two_pi)(X) ∪ periodise(cos_reverse, two_pi)(X)
+periodise(cos_full, two_pi)(X)
 
 # Reverse function for cos; does not alter y
 """

test/Non1788tests/inv_trig.jl

@@ -32,3 +32,8 @@ end
     @test atan_rev(entireinterval(Float64), entireinterval(Float64))[2] == Interval(-∞, ∞)
     @test atan_rev(Interval(-Inf, 0.0), entireinterval(Float64))[2] == Interval(-∞, ∞)
 end
+
+@testset "Special cases" begin
+    @test sin_rev(0..0, 0..0) == (0..0, 0..0)
+    @test cos_rev(1..1, 0..0) == (1..1, 0..0)
+end