Merge pull request #33308 from JuliaLang/jq/compactfloat

Fix #33185 by rounding to 6 significant digits while printing float d…

Author: quinnj

base/ryu/Ryu.jl

@@ -10,7 +10,7 @@ neededdigits(::Type{Float32}) = 39 + 9 + 2
 neededdigits(::Type{Float16}) = 9 + 5 + 9
 
 """
-    Ryu.writeshortest(x, plus=false, space=false, hash=true, precision=-1, expchar=UInt8('e'), padexp=false, decchar=UInt8('.'))
+    Ryu.writeshortest(x, plus=false, space=false, hash=true, precision=-1, expchar=UInt8('e'), padexp=false, decchar=UInt8('.'), typed=false, compact=false)
     Ryu.writeshortest(buf::Vector{UInt8}, pos::Int, x, args...)
 
 Convert a float value `x` into its "shortest" decimal string, which can be parsed back to the same value.
@@ -21,10 +21,12 @@ Various options for the output format include:
   * `plus`: for positive `x`, prefix decimal string with a `'+'` character
   * `space`: for positive `x`, prefix decimal string with a `' '` character; overridden if `plus=true`
   * `hash`: whether the decimal point should be written, even if no additional digits are needed for precision
-  * `precision`: minimum number of significant digits to be included in the decimal string; extra `'0'` characters will be added for padding if necessary
+  * `precision`: minimum number of digits to be included in the decimal string; extra `'0'` characters will be added for padding if necessary
   * `expchar`: character to use exponent component in scientific notation
   * `padexp`: whether two digits should always be written, even for single-digit exponents (e.g. `e+1` becomes `e+01`)
   * `decchar`: decimal point character to be used
+  * `typed`: whether additional type information should be printed for `Float16` / `Float32`
+  * `compact`: output will be limited to 6 significant digits
 """
 function writeshortest(x::T,
         plus::Bool=false,
@@ -33,17 +35,19 @@ function writeshortest(x::T,
         precision::Integer=-1,
         expchar::UInt8=UInt8('e'),
         padexp::Bool=false,
-        decchar::UInt8=UInt8('.')) where {T <: Base.IEEEFloat}
+        decchar::UInt8=UInt8('.'),
+        typed::Bool=false,
+        compact::Bool=false) where {T <: Base.IEEEFloat}
     buf = Base.StringVector(neededdigits(T))
-    pos = writeshortest(buf, 1, x)
+    pos = writeshortest(buf, 1, x, plus, space, hash, precision, expchar, padexp, decchar, typed, compact)
     return String(resize!(buf, pos - 1))
 end
 
 """
-    Ryu.writefixed(x, plus=false, space=false, hash=true, precision=-1, decchar=UInt8('.'))
+    Ryu.writefixed(x, precision, plus=false, space=false, hash=false, decchar=UInt8('.'), trimtrailingzeros=false)
     Ryu.writefixed(buf::Vector{UInt8}, pos::Int, x, args...)
 
-Convert a float value `x` into a "fixed" size decimal string.
+Convert a float value `x` into a "fixed" size decimal string of the provided precision.
 This function allows achieving the `%f` printf format.
 Note the 2nd method allows passing in a byte buffer and position directly; callers must ensure the buffer has sufficient room to hold the entire decimal string.
 
@@ -53,15 +57,22 @@ Various options for the output format include:
   * `hash`: whether the decimal point should be written, even if no additional digits are needed for precision
   * `precision`: minimum number of significant digits to be included in the decimal string; extra `'0'` characters will be added for padding if necessary
   * `decchar`: decimal point character to be used
+  * `trimtrailingzeros`: whether trailing zeros should be removed
 """
-function writefixed(x::T, precision) where {T <: Base.IEEEFloat}
+function writefixed(x::T,
+    precision::Integer,
+    plus::Bool=false,
+    space::Bool=false,
+    hash::Bool=false,
+    decchar::UInt8=UInt8('.'),
+    trimtrailingzeros::Bool=false) where {T <: Base.IEEEFloat}
     buf = Base.StringVector(precision + neededdigits(T))
-    pos = writefixed(buf, 1, x, false, false, false, precision)
+    pos = writefixed(buf, 1, x, precision, plus, space, hash, decchar, trimtrailingzeros)
     return String(resize!(buf, pos - 1))
 end
 
 """
-    Ryu.writeexp(x, plus=false, space=false, hash=true, precision=-1, expchar=UInt8('e'), decchar=UInt8('.'))
+    Ryu.writeexp(x, precision, plus=false, space=false, hash=false, expchar=UInt8('e'), decchar=UInt8('.'), trimtrailingzeros=false)
     Ryu.writeexp(buf::Vector{UInt8}, pos::Int, x, args...)
 
 Convert a float value `x` into a scientific notation decimal string.
@@ -75,32 +86,38 @@ Various options for the output format include:
   * `precision`: minimum number of significant digits to be included in the decimal string; extra `'0'` characters will be added for padding if necessary
   * `expchar`: character to use exponent component in scientific notation
   * `decchar`: decimal point character to be used
+  * `trimtrailingzeros`: whether trailing zeros should be removed
 """
-function writeexp(x::T, precision) where {T <: Base.IEEEFloat}
+function writeexp(x::T,
+    precision::Integer,
+    plus::Bool=false,
+    space::Bool=false,
+    hash::Bool=false,
+    expchar::UInt8=UInt8('e'),
+    decchar::UInt8=UInt8('.'),
+    trimtrailingzeros::Bool=false) where {T <: Base.IEEEFloat}
     buf = Base.StringVector(precision + neededdigits(T))
-    pos = writeexp(buf, 1, x, false, false, false, precision)
+    pos = writeexp(buf, 1, x, precision, plus, space, hash, expchar, decchar, trimtrailingzeros)
     return String(resize!(buf, pos - 1))
 end
 
-function Base.show(io::IO, x::T) where {T <: Base.IEEEFloat}
-    if get(io, :compact, false)
-        x = round(x, sigdigits=6)
-    end
+function Base.show(io::IO, x::T, forceuntyped::Bool=false) where {T <: Base.IEEEFloat}
+    compact = get(io, :compact, false)
     buf = Base.StringVector(neededdigits(T))
-    typed = !get(io, :compact, false) && get(io, :typeinfo, Any) != typeof(x)
+    typed = !forceuntyped && !compact && get(io, :typeinfo, Any) != typeof(x)
     pos = writeshortest(buf, 1, x, false, false, true, -1,
-        x isa Float32 ? UInt8('f') : UInt8('e'), false, UInt8('.'), typed)
+        x isa Float32 ? UInt8('f') : UInt8('e'), false, UInt8('.'), typed, compact)
     write(io, resize!(buf, pos - 1))
     return
 end
 
 function Base.string(x::T) where {T <: Base.IEEEFloat}
     buf = Base.StringVector(neededdigits(T))
     pos = writeshortest(buf, 1, x, false, false, true, -1,
-        x isa Float32 ? UInt8('f') : UInt8('e'), false, UInt8('.'), false)
+        x isa Float32 ? UInt8('f') : UInt8('e'), false, UInt8('.'), false, false)
     return String(resize!(buf, pos - 1))
 end
 
-Base.print(io::IO, x::Union{Float16, Float32}) = show(IOContext(io, :compact => true), x)
+Base.print(io::IO, x::Union{Float16, Float32}) = show(io, x, true)
 
 end # module

base/ryu/exp.jl

@@ -1,6 +1,6 @@
 @inline function writeexp(buf, pos, v::T,
-    plus=false, space=false, hash=false,
-    precision=-1, expchar=UInt8('e'), decchar=UInt8('.'), trimtrailingzeros=false) where {T <: Base.IEEEFloat}
+    precision=-1, plus=false, space=false, hash=false,
+    expchar=UInt8('e'), decchar=UInt8('.'), trimtrailingzeros=false) where {T <: Base.IEEEFloat}
     @assert 0 < pos <= length(buf)
     x = Float64(v)
     neg = signbit(x)

base/ryu/fixed.jl

@@ -1,6 +1,6 @@
 @inline function writefixed(buf, pos, v::T,
-    plus=false, space=false, hash=false,
-    precision=-1, decchar=UInt8('.'), trimtrailingzeros=false) where {T <: Base.IEEEFloat}
+    precision=-1, plus=false, space=false, hash=false,
+    decchar=UInt8('.'), trimtrailingzeros=false) where {T <: Base.IEEEFloat}
     @assert 0 < pos <= length(buf)
     x = Float64(v)
     neg = signbit(x)

base/ryu/shortest.jl

@@ -1,6 +1,6 @@
 @inline function writeshortest(buf::Vector{UInt8}, pos, x::T,
     plus=false, space=false, hash=true,
-    precision=-1, expchar=UInt8('e'), padexp=false, decchar=UInt8('.'), typed=false) where {T}
+    precision=-1, expchar=UInt8('e'), padexp=false, decchar=UInt8('.'), typed=false, compact=false) where {T}
     @assert 0 < pos <= length(buf)
     neg = signbit(x)
     # special cases
@@ -242,6 +242,36 @@
         pos += 1
     end
 
+    if compact && output > 999999
+        lastdigit = output % 10
+        while true
+            output = div(output, 10)
+            nexp += nexp != 0
+            output > 999999 || break
+            lastdigit = output % 10
+        end
+        if lastdigit == 9
+            output += 1
+            lastdigit = 0
+        end
+        if lastdigit == 9
+            while true
+                output = div(output, 10)
+                nexp += nexp != 0
+                output % 10 == 9 || break
+            end
+            output += 1
+        elseif output % 10 == 0
+            while true
+                output = div(output, 10)
+                nexp += nexp != 0
+                output % 10 == 0 || break
+            end
+        else
+            output += lastdigit > 4
+        end
+    end
+
     olength = decimallength(output)
     exp_form = true
     pt = nexp + olength

test/ryu.jl

@@ -736,4 +736,26 @@ end
 
 end # exp
 
+@testset "compact" begin
+
+    writecompact(x) = Ryu.writeshortest(x, false, false, true, -1, UInt8('e'), false, UInt8('.'), false, true)
+
+    @test writecompact(0.49999999) == "0.5"
+    @test writecompact(0.459999999) == "0.46"
+    @test writecompact(0.20058603493384108) == "0.200586"
+    @test writecompact(0.9999999) == "1.0"
+    @test writecompact(0.1999999) == "0.2"
+    @test writecompact(123.4567) == "123.457"
+    @test writecompact(0.001234567) == "0.00123457"
+    @test writecompact(0.1234567) == "0.123457"
+    @test writecompact(1234567.0) == "123457.0"
+    @test writecompact(12345678910.0) == "1.23457e10"
+    @test writecompact(12345678.0) == "123457.0"
+    @test writecompact(0.10000049) == "0.1"
+    @test writecompact(22.89825) == "22.8983"
+    @test writecompact(0.646690981531646) == "0.646691"
+    @test writecompact(6.938893903907228e-17) == "6.93889e-17"
+
+end
+
 end # Ryu