StackOverflowError using @printf

[GregPlowman]

using MultiFloats
using Printf
@printf("%f", Float64x2(3))

ERROR: StackOverflowError:
Stacktrace:
 [1] fix_dec(::MultiFloat{Float64,2}, ::Int64, ::Array{UInt8,1}) at .\printf.jl:987 (repeats 80000 times)

Probably similar to issue with DoubleFloats:

• stack overflow using Optim.jl with Double64 JuliaMath/DoubleFloats.jl#81
• printf (fix_dec) error on Julia v1.0  JuliaMath/DoubleFloats.jl#88
• Printf.fix_dec and ini_dec for Julia v1.0 JuliaMath/DoubleFloats.jl#84

[dzhang314]

Hey Greg, thanks for taking a look at my project! I'm also aware of the issue and working on a fix, forwarding Base.Printf calls for MultiFloat{T,N} through conversion to BigFloat, just like I've done with Base.show. This is kind of janky, but print performance isn't a very high priority for me, so for interactive use this ought to be sufficient.

[GregPlowman]

Here's a possible solution:

using MultiFloats
using Printf

import Printf: fix_dec, ini_dec

if VERSION < v"1.1"
    fix_dec(out, d::MultiFloat, flags::String, width::Int, precision::Int, c::Char) =
        fix_dec(out, BigFloat(d), flags, width, precision, c)

    ini_dec(out, d::MultiFloat, ndigits::Int, flags::String, width::Int, precision::Int, c::Char) =
        ini_dec(out, BigFloat(d), ndigits, flags, width, precision, c)
else
    fix_dec(out, d::MultiFloat, flags::String, width::Int, precision::Int, c::Char, digits) =
        fix_dec(out, BigFloat(d), flags, width, precision, c, digits)

    ini_dec(out, d::MultiFloat, ndigits::Int, flags::String, width::Int, precision::Int, c::Char, digits) =
        ini_dec(out, BigFloat(d), ndigits, flags, width, precision, c, digits)
end

[dzhang314]

@GregPlowman Nice, thanks! There needs to be a little more logic involving renormalization and setprecision to ensure that no bits are lost in the conversion to BigFloat, but it looks like those are definitely the right functions to implement. I really appreciate the tip about Julia versions, by the way -- I probably wouldn't have caught that myself.

Would you like to be credited in any way besides a mention in this comment?

[GregPlowman]

Just updated to new version. All looks good.
Thanks for fixing this, and fast response.
(Please, no need for credit/mention)