Merge pull request #562 from OlivierHnt/1.0-dev-trig

1.0-dev: fix stack overflow error (#513, #538)

Author: Kolaru

src/IntervalArithmetic.jl

@@ -23,7 +23,8 @@ import Base:
     <, >, ==, !=, ⊆, ^, <=, >=,
     in, zero, one, eps, typemin, typemax, abs, abs2, min, max,
     sqrt, exp, log, exp2, exp10, log2, log10, inv, cbrt, hypot,
-    sin, cos, tan, cot, csc, sec, asin, acos, atan, acot, sinpi, cospi,
+    rad2deg, deg2rad,
+    sin, cos, tan, cot, csc, sec, asin, acos, atan, acot, sinpi, cospi, sincospi,
     sinh, cosh, tanh, coth, csch, sech, asinh, acosh, atanh, acoth,
     union, intersect, isempty,
     convert, eltype, size,

src/intervals/arithmetic/trigonometric.jl

@@ -2,6 +2,16 @@
 # Section 9.1 of the IEEE Standard 1788-2015 and required for set-based flavor
 # in Section 10.5.3
 
+# needed to prevent stack overflow
+
+rad2deg(x::Interval) = (x / π) * 180
+
+deg2rad(x::Interval) = (x * π) / 180
+
+sincospi(x::Interval) = (sinpi(x), cospi(x))
+
+#
+
 const halfpi = π / 2
 
 half_pi(::Type{T}) where {T<:NumTypes} = unsafe_scale(convert(T, 0.5), interval(T, π))
@@ -132,10 +142,7 @@ function sin(a::Interval{Float64})
     end
 end
 
-function sinpi(a::Interval{T}) where {T<:NumTypes}
-    isempty(a) && return a
-    return sin(a * interval(T, π))
-end
+sinpi(a::Interval) = sin(a * π)
 
 """
     cos(a::Interval)
@@ -225,10 +232,7 @@ function cos(a::Interval{Float64})
     end
 end
 
-function cospi(a::Interval{T}) where {T<:NumTypes}
-    isempty(a) && return a
-    return cos(a * interval(T, π))
-end
+cospi(a::Interval) = cos(a * π)
 
 """
     tan(a::Interval)

test/interval_tests/trig.jl

@@ -1,6 +1,11 @@
 using Test
 using IntervalArithmetic
 
+@testset "rad2deg/deg2rad" begin
+    @test rad2deg(π .. 2π) ⊇ interval(180, 360)
+    @test deg2rad(180 .. 360) ⊇ interval(π, 2interval(π))
+end
+
 @testset "sin" begin
     @test sin(interval(0.5)) ≛ interval(0.47942553860420295, 0.47942553860420301)
     @test sin(interval(0.5, 1.67)) ≛ interval(4.7942553860420295e-01, 1.0)
@@ -37,8 +42,8 @@ end
 
 @testset "sinpi" begin
     @test sinpi(∅) ≛ ∅
-    @test sinpi(0.5 .. 1.5) ≛ interval(-1 , 1)
     @test sinpi(1 .. 2) ⊇ interval(-1 , 0)
+    @test sinpi(0.5 .. 1.5) ≛ interval(-1 , 1)
     @test sinpi(0.25 .. 0.75) ⊇ interval(1/sqrt(2) , 1)
     @test sinpi(-0.25 .. 0.25) ⊇ interval(-1/sqrt(2) , 1/sqrt(2))
 end
@@ -51,6 +56,19 @@ end
     @test cospi(-0.25 .. 0.25) ≛ interval(1/sqrt(2) , 1)
 end
 
+@testset "sincospi" begin
+    x = sincospi(∅)
+    @test (x[1] == ∅) & (x[2] == ∅)
+    x = sincospi(1 .. 2)
+    @test (x[1] ⊇ interval(-1 , 0)) & (x[2] ≛ interval(-1 , 1))
+    x = sincospi(0.5 .. 1.5)
+    @test (x[1] ≛ interval(-1 , 1)) & (x[2] ⊇ interval(-1 , 0))
+    x = sincospi(0.25 .. 0.75)
+    @test (x[1] ⊇ interval(1/sqrt(2) , 1)) & (x[2] ⊇ interval(-1/sqrt(2) , 1/sqrt(2)))
+    x = sincospi(-0.25 .. 0.25)
+    @test (x[1] ⊇ interval(-1/sqrt(2) , 1/sqrt(2))) & (x[2] ≛ interval(1/sqrt(2) , 1))
+end
+
 @testset "tan" begin
     @test tan(interval(0.5)) ≛ interval(0.54630248984379048, 0.5463024898437906)
     @test tan(interval(0.5, 1.67)) ≛ entireinterval()