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Add big() and rationalize() for FixedPoint #186

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Merged
merged 1 commit into from
Jul 12, 2020
Merged

Add big() and rationalize() for FixedPoint #186

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10 changes: 9 additions & 1 deletion src/FixedPointNumbers.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@ import Base: ==, <, <=, -, +, *, /, ~, isapprox,
convert, promote_rule, show, isinteger, abs, decompose,
isnan, isinf, isfinite,
zero, oneunit, one, typemin, typemax, floatmin, floatmax, eps, reinterpret,
float, trunc, round, floor, ceil, bswap,
big, rationalize, float, trunc, round, floor, ceil, bswap,
div, fld, rem, mod, mod1, fld1, min, max, minmax,
rand, length

Expand Down Expand Up @@ -71,6 +71,14 @@ function (::Type{Ti})(x::FixedPoint) where {Ti <: Integer}
end
Base.Rational{Ti}(x::FixedPoint) where {Ti <: Integer} = Rational{Ti}(Rational(x))

big(::Type{<:FixedPoint}) = BigFloat
big(x::FixedPoint) = convert(BigFloat, x)

rationalize(x::FixedPoint; tol::Real=eps(x)) = rationalize(Int, x, tol=tol)
function rationalize(::Type{Ti}, x::FixedPoint; tol::Real=eps(x)) where Ti <: Integer
tol <= eps(x) ? Rational{Ti}(x) : rationalize(Ti, float(x), tol)
end

"""
isapprox(x::FixedPoint, y::FixedPoint; rtol=0, atol=max(eps(x), eps(y)))

Expand Down
2 changes: 1 addition & 1 deletion src/normed.jl
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Expand Up @@ -244,7 +244,7 @@ function Base.Float64(x::Normed{UInt128,f}) where f
end
end

Base.BigFloat(x::Normed) = reinterpret(x)*(1/BigFloat(rawone(x)))
Base.BigFloat(x::Normed) = reinterpret(x) / BigFloat(rawone(x))

Base.Rational(x::Normed) = reinterpret(x)//rawone(x)

Expand Down
26 changes: 15 additions & 11 deletions test/fixed.jl
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Expand Up @@ -253,14 +253,6 @@ end
@test varm(a, m) === varm(af, m)
end

@testset "convert result type" begin
x = Fixed{Int8,7}(0.75)
for T in (Float16, Float32, Float64, BigFloat)
y = convert(T, x)
@test isa(y, T)
end
end

@testset "bool conversions" begin
@test convert(Bool, 0.0Q1f6) === false
@test convert(Bool, 1.0Q1f6) === true
Expand All @@ -269,7 +261,7 @@ end
@test_broken convert(Bool, Fixed{Int8,8}(0.2)) # TODO: remove this
end

@testset "Integer conversions" begin
@testset "integer conversions" begin
@test convert(Int, Q1f6(1)) === 1
@test convert(Integer, Q1f6(1)) === Int8(1)
@test convert(UInt, 1Q1f6) === UInt(1)
Expand All @@ -280,7 +272,19 @@ end
@testset "rational conversions" begin
@test convert(Rational, -0.75Q1f6) === Rational{Int8}(-3//4)
@test convert(Rational, -0.75Q0f7) === Rational{Int16}(-3//4)
@test convert(Rational{Int}, -0.75Q0f7) === Rational(-3//4)
@test convert(Rational{Int}, -0.75Q0f7) === Rational{Int}(-3//4)

@test rationalize(-0.75Q3f4) === Rational{Int}(-3//4)
@test rationalize(Int16, 0.81Q3f4) === Rational{Int16}(13//16)
@test rationalize(-0.81Q3f4, tol=0.02) === Rational{Int}(-13//16)
@test rationalize(Int8, -0.81Q3f4, tol=0.07) === Rational{Int8}(-3//4)
end

@testset "BigFloat conversions" begin
@test convert(BigFloat, -0.75Q0f7)::BigFloat == big"-0.75"

@test big(Q7f0) === BigFloat # !== BigInt
@test big(0.75Q3f4)::BigFloat == big"0.75"
end

@testset "Floating-point conversions" begin
Expand All @@ -290,7 +294,7 @@ end
end

@testset "conversions to float" begin
for T in (Float16, Float32, Float64, BigFloat)
for T in (Float16, Float32, Float64)
@test isa(convert(T, Q0f7(0.3)), T)
end

Expand Down
21 changes: 19 additions & 2 deletions test/normed.jl
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Expand Up @@ -110,7 +110,6 @@ end
@test convert(Integer, one(T)) == 1
@test convert(Rational, one(T)) == 1
end
@test convert(Rational, convert(N0f8, 0.5)) == 0x80//0xff
@test convert(N0f16, one(N0f8)) === one(N0f16)
@test convert(N0f16, N0f8(0.5)).i === 0x8080
@test convert(Normed{UInt16,7}, Normed{UInt8,7}(0.504)) === Normed{UInt16,7}(0.504)
Expand All @@ -124,6 +123,24 @@ end
@test_throws InexactError convert(Int8, 256N8f8)
end

@testset "rational conversions" begin
@test convert(Rational, 0.5N0f8) === Rational{UInt8}(0x80//0xff)
@test convert(Rational, 0.5N4f12) === Rational{UInt16}(0x800//0xfff)
@test convert(Rational{Int}, 0.5N0f8) === Rational{Int}(0x80//0xff)

@test rationalize(0.8N0f8) === Rational{Int}(4//5)
@test rationalize(Int16, 0.804N0f8) === Rational{Int16}(41//51)
@test rationalize(0.804N0f8, tol=0.002) === Rational{Int}(41//51)
@test rationalize(Int8, 0.804N0f8, tol=0.005) === Rational{Int8}(4//5)
end

@testset "BigFloat conversions" begin
@test convert(BigFloat, 0.5N0f8)::BigFloat == 128 / big"255"

@test big(N7f1) === BigFloat # !== BigInt
@test big(0.5N4f4)::BigFloat == 8 / big"15"
end

@testset "conversion from float" begin
# issue 102
for T in (UInt8, UInt16, UInt32, UInt64, UInt128)
Expand Down Expand Up @@ -158,7 +175,7 @@ end

@testset "conversions to float" begin
x = N0f8(0.3)
for T in (Float16, Float32, Float64, BigFloat)
for T in (Float16, Float32, Float64)
y = convert(T, x)
@test isa(y, T)
end
Expand Down