Improvements to random octonion generation (#19)

* Don't use `@irrational`

* Deprecate octorand

* Remove octorand export

* Increment version number

Project.toml

@@ -1,6 +1,6 @@
 name = "Octonions"
 uuid = "d00ba074-1e29-4f5e-9fd4-d67071d6a14d"
-version = "0.2.2"
+version = "0.2.3"
 
 [deps]
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"

src/Octonions.jl

@@ -3,11 +3,9 @@ module Octonions
 using Random
 using RealDot: RealDot
 
-Base.@irrational INV_SQRT_EIGHT 0.3535533905932737622004 sqrt(big(0.125))
-
 include("octonion.jl")
 
 export Octonion, OctonionF16, OctonionF32, OctonionF64
-export imag_part, octo, octorand
+export imag_part, octo
 
 end # module

src/octonion.jl

@@ -205,23 +205,24 @@ end
 
 Base.:^(o::Octonion, w::Octonion) = exp(w * log(o))
 
-octorand(rng::AbstractRNG = Random.GLOBAL_RNG) = octo(randn(rng), randn(rng), randn(rng), randn(rng), randn(rng), randn(rng), randn(rng), randn(rng))
+Base.@deprecate octorand(rng::AbstractRNG=Random.GLOBAL_RNG) randn(rng, OctonionF64)*sqrt(8)
 
 function Base.rand(rng::AbstractRNG, ::Random.SamplerType{Octonion{T}}) where {T<:Real}
   Octonion{T}(rand(rng, T), rand(rng, T), rand(rng, T), rand(rng, T),
               rand(rng, T), rand(rng, T), rand(rng, T), rand(rng, T))
 end
 
 function Base.randn(rng::AbstractRNG, ::Type{Octonion{T}}) where {T<:AbstractFloat}
+  scale = inv(sqrt(T(8)))
   Octonion{T}(
-      randn(rng, T) * INV_SQRT_EIGHT,
-      randn(rng, T) * INV_SQRT_EIGHT,
-      randn(rng, T) * INV_SQRT_EIGHT,
-      randn(rng, T) * INV_SQRT_EIGHT,
-      randn(rng, T) * INV_SQRT_EIGHT,
-      randn(rng, T) * INV_SQRT_EIGHT,
-      randn(rng, T) * INV_SQRT_EIGHT,
-      randn(rng, T) * INV_SQRT_EIGHT,
+      randn(rng, T) * scale,
+      randn(rng, T) * scale,
+      randn(rng, T) * scale,
+      randn(rng, T) * scale,
+      randn(rng, T) * scale,
+      randn(rng, T) * scale,
+      randn(rng, T) * scale,
+      randn(rng, T) * scale,
   )
 end
 

test/octonion.jl

@@ -97,6 +97,7 @@ end
 
     @testset "random generation" begin
         @testset "octorand" begin
+            @test_deprecated octorand()
             o = octorand()
             @test o isa Octonion
         end