ARROW-3680: [Go] implement Float16 array

[anson627]

No description provided.

[anson627]

@sbinet

[sbinet]

thanks for tackling this!

[sbinet]

ping?

[codecov-io]

Codecov Report

Merging #4083 into master will decrease coverage by 16.07%.
The diff coverage is 55.64%.

@@             Coverage Diff             @@
##           master    #4083       +/-   ##
===========================================
- Coverage   87.91%   71.83%   -16.08%     
===========================================
  Files         739       74      -665     
  Lines       90980     6072    -84908     
  Branches     1252        0     -1252     
===========================================
- Hits        79985     4362    -75623     
+ Misses      10876     1476     -9400     
- Partials      119      234      +115

Impacted Files	Coverage Δ
go/arrow/datatype_fixedwidth.go	20% <ø> (-11.25%)	⬇️
go/arrow/type_traits_float16.go	0% <0%> (ø)
go/arrow/array/builder.go	66.91% <0%> (-0.51%)	⬇️
go/arrow/array/array.go	95.16% <0%> (-1.57%)	⬇️
go/arrow/array/float16.go	50% <50%> (ø)
go/arrow/array/float16_builder.go	75.34% <75.34%> (ø)
go/arrow/math/uint64_sse4_amd64.go	0% <0%> (-100%)	⬇️
go/arrow/math/float64_sse4_amd64.go	0% <0%> (-100%)	⬇️
go/arrow/memory/memory_sse4_amd64.go	0% <0%> (-100%)	⬇️
go/arrow/math/int64_sse4_amd64.go	0% <0%> (-100%)	⬇️
... and 714 more

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[anson627]

ping?

Done, let me know any other refactoring I can make, then I will focus on adding more unit tests.

[anson627]

ping?

Done, let me know any other refactoring I can make, then I will focus on adding more unit tests.

ping?

[sbinet]

apologies for the belated review.

[stuartcarnie]

I'd like to remove the float16.Float16 stutter if possible. Looking for suggestions or ideas

[sbinet]

actually, independantly of how one would call that type, I would perhaps change its definition to:

type Float16 struct { v uint16 }

to prevent mistakes such as:

var v float16.Float16 = 3 // oops... this compiles. it shouldn't.

https://play.golang.org/p/91qGe456FPA

[wesm]

How is it going with this patch?

[anson627]

I will make the change accordingly.

[sbinet]

ping? (it'd be great to have this in 0.14 and have this in sooner than later so I can update the IPC code to handle float16 arrays :P)

[anson627]

ping? (it'd be great to have this in 0.14 and have this in sooner than later so I can update the IPC code to handle float16 arrays :P)

done

[sbinet]

LGTM modulo my very last nit-picks (promised!)

thanks again.

[anson627]

Done. Thank you for all the suggestion! I learnt a lot.

[sbinet]

(travis failure unrelated)

well, thank you for being so tenacious :)