type number = | F32| F64| C32| C64
type ('a, 'b) owl_arr =
('a, 'b, Stdlib.Bigarray.c_layout) Stdlib.Bigarray.Genarray.ttype index = | I of int| L of int list| R of int list
type index_ = | I_ of int| L_ of int array| R_ of int array
type padding = | SAME| VALID
type device_type = | CPU| OpenCL| CUDA