Missing methods erf(x, RoundUp)

[dpsanders]

We're missing methods like erf(x, RoundUp).

cc @SebastianM-C

[SebastianM-C]

I am not sure I understand what this part does:

for f in (:erf, :erfc)

    @eval function($f)(x::BigFloat, r::RoundingMode)
        setrounding(BigFloat, r) do
            ($f)(x)
        end
    end

    @eval ($f)(a::Interval{Float64}) = convert(Interval{Float64}, ($f)(big53(a)))

end

Was this not supposed to define the versions of the functions for all rounding modes?

[dpsanders]

Yes, but in line 3 you can see that it only does it for x that is a BigFloat.

[dpsanders]

It uses metaprogramming to automate the generation instead of repeating very similar code twice.
But we can equally just repeat the code twice, which may well be clearer!

[SebastianM-C]

The metaprogramming part was quite clear, but I am not sure about the setrounding part.

Would it be better to use a parametric type instead of BigFloat or should we define explicitly what happens?

[dpsanders]

As far as I remember / can see, we have correctly rounded functions only for BigFloat.
So the Float64 ones will have to be defined in terms of those.