Use JuliaLibm log functions in Main.Math.

[pkofod]

These should be just as precise as openlibm (own experience and https://tpapp.github.io/post/log1p/ ) but I will ofc provide solid numbers on this.

@stevengj raised the point that it's concerning that log1p seems a bit slower for small values as per the blog post above, and these are the values where you really want log1p. I'll benchmark this further and if it is the case, my idea is to do openlibm port for the small x part and tang's for the larger x's.

Should the old ones (those in a module) be deprecated? They've been mentioned in the docstrings, so...

[pkofod]

Float64
If we look at log it seems to be a straight improvement in precision at the evaluated points.

The same thing goes for timings

So log for Float64 seems like a pareto improvement.

Float32
Precision

Speed

Slightly slower around 1.

cc: @simonbyrne
code appendix: https://gist.github.com/pkofod/0e361627401c894135ac139c71e538ea

[pkofod]

Should the JuliaLibm-module part of it be deprecated as it's been mentioned in the docstrings?

[ararslan]

I doubt anyone has been relying on Base.Math.JuliaLibm so I don't see a need to deprecate it.

[pkofod]

I doubt anyone has been relying on Base.Math.JuliaLibm so I don't see a need to deprecate it.

Alright, I was only wondering since it's actually mentioned in the docstring of log, but fine by me. I should just remove it then?

[vchuravy]

I would say it is better to be conservative and deprecate them properly.

[pkofod]

I would say it is better to be conservative and deprecate them properly.

Is there a special syntax that lets you deprecate unexported functions from modules?

[vchuravy]

@eval Math.JuliaLibm begin
    Base.@deprecate ...
end

[ararslan]

You could just move the whole definition here:

@eval Base.Math module JuliaLibm
    Base.@deprecate log Base.log
end

[pkofod]

Will fix!

[pkofod]

Errors seem unrelated?

[pkofod]

Shameless bump. This is approved by two people, and tests seem to pass, so I am wondering if there is more I need to do.