Bigarrays not specialized enough

[Chris00]

In signatures such as

val polyline
  :  ?linetype:linetype
  -> ?linewidth:float
  -> ?coloridx:int
  -> (float, 'a, 'b) Bigarray.Genarray.t
  -> (float, 'c, 'd) Bigarray.Genarray.t
  -> unit

the bigarray must be mandated to carry float64 values.

Also, I do not understand the reason for not using Array1.t (or Array2.t when fit) bigarrays.

[mseri]

The reason I kept it like that, if I remember correctly, is to be able to use views into owl's ndarrays without having to convert them to Array1 or Array2 and because I was planning to add a safer and higher level interface (I still have to find time for that unfortunately).

I like your suggestion but currently I don't have the time to revise the full api. I will leave the issue open if you or anybody else want to send a PR for this.