module Bigarray: sig endThis module implements multi-dimensional arrays of integers and floating-point numbers, thereafter referred to as ``big arrays''. The implementation allows efficient sharing of large numerical arrays between Caml code and C or Fortran numerical libraries.
Concerning the naming conventions, users of this module are encouraged
to do open Bigarray in their source, then refer to array types and
operations via short dot notation, e.g. Array1.t or Array2.sub.
Big arrays support all the Caml ad-hoc polymorphic operations:
=, <>, <=, etc, as well as Pervasives.compare);Hash);Pervasives.output_value
and Pervasives.input_value, as well as the functions from the
Marshal module).
Element kinds
|
Bigarray.float32_elt),Bigarray.float64_elt),Bigarray.complex32_elt),Bigarray.complex64_elt),Bigarray.int8_signed_elt or Bigarray.int8_unsigned_elt),Bigarray.int16_signed_elt or Bigarray.int16_unsigned_elt),Bigarray.int_elt),Bigarray.int32_elt),Bigarray.int64_elt),Bigarray.nativeint_elt).type
type
type
type
type
type
type
type
type
type
type
type
type ('a, 'b) kind
float32_elt contains
32-bit single precision floats, but reading or writing one of
its elements from Caml uses the Caml type float, which is
64-bit double precision floats.
The abstract type ('a, 'b) kind captures this association
of a Caml type 'a for values read or written in the big array,
and of an element kind 'b which represents the actual contents
of the big array. The following predefined values of type
kind list all possible associations of Caml types with
element kinds:
val float32 : (float, float32_elt) kindBigarray.char.val float64 : (float, float64_elt) kindBigarray.char.val complex32 : (Complex.t, complex32_elt) kindBigarray.char.val complex64 : (Complex.t, complex64_elt) kindBigarray.char.val int8_signed : (int, int8_signed_elt) kindBigarray.char.val int8_unsigned : (int, int8_unsigned_elt) kindBigarray.char.val int16_signed : (int, int16_signed_elt) kindBigarray.char.val int16_unsigned : (int, int16_unsigned_elt) kindBigarray.char.val int : (int, int_elt) kindBigarray.char.val int32 : (int32, int32_elt) kindBigarray.char.val int64 : (int64, int64_elt) kindBigarray.char.val nativeint : (nativeint, nativeint_elt) kindBigarray.char.val char : (char, int8_unsigned_elt) kindfloat32_elt and float64_elt are
accessed using the Caml type float. Big arrays of complex kinds
complex32_elt, complex64_elt are accessed with the Caml type
Complex.t. Big arrays of
integer kinds are accessed using the smallest Caml integer
type large enough to represent the array elements:
int for 8- and 16-bit integer bigarrays, as well as Caml-integer
bigarrays; int32 for 32-bit integer bigarrays; int64
for 64-bit integer bigarrays; and nativeint for
platform-native integer bigarrays. Finally, big arrays of
kind int8_unsigned_elt can also be accessed as arrays of
characters instead of arrays of small integers, by using
the kind value char instead of int8_unsigned.
Array layouts
|
type
type
In the C-style layout, array indices start at 0, and
multi-dimensional arrays are laid out in row-major format.
That is, for a two-dimensional array, all elements of
row 0 are contiguous in memory, followed by all elements of
row 1, etc. In other terms, the array elements at (x,y)
and (x, y+1) are adjacent in memory.
In the Fortran-style layout, array indices start at 1, and
multi-dimensional arrays are laid out in column-major format.
That is, for a two-dimensional array, all elements of
column 0 are contiguous in memory, followed by all elements of
column 1, etc. In other terms, the array elements at (x,y)
and (x+1, y) are adjacent in memory.
Each layout style is identified at the type level by the
abstract types Bigarray.c_layout and fortran_layout respectively.
type 'a layout
'a layout represents one of the two supported
memory layouts: C-style if 'a is Bigarray.c_layout, Fortran-style
if 'a is Bigarray.fortran_layout.
Supported layouts
|
The abstract values c_layout and fortran_layout represent
the two supported layouts at the level of values.
val c_layout : c_layout layoutval fortran_layout : fortran_layout layout
Generic arrays (of arbitrarily many dimensions)
|
module Genarray: sig end
One-dimensional arrays
|
module Array1: sig end
Two-dimensional arrays
|
module Array2: sig end
Three-dimensional arrays
|
module Array3: sig end
Coercions between generic big arrays and fixed-dimension big arrays
|
val genarray_of_array1 : ('a, 'b, 'c) Array1.t -> ('a, 'b, 'c) Genarray.tval genarray_of_array2 : ('a, 'b, 'c) Array2.t -> ('a, 'b, 'c) Genarray.tval genarray_of_array3 : ('a, 'b, 'c) Array3.t -> ('a, 'b, 'c) Genarray.tval array1_of_genarray : ('a, 'b, 'c) Genarray.t -> ('a, 'b, 'c) Array1.tInvalid_arg if the generic big array
does not have exactly one dimension.val array2_of_genarray : ('a, 'b, 'c) Genarray.t -> ('a, 'b, 'c) Array2.tInvalid_arg if the generic big array
does not have exactly two dimensions.val array3_of_genarray : ('a, 'b, 'c) Genarray.t -> ('a, 'b, 'c) Array3.tInvalid_arg if the generic big array
does not have exactly three dimensions.
Re-shaping big arrays
|
val reshape : ('a, 'b, 'c) Genarray.t ->
int array -> ('a, 'b, 'c) Genarray.treshape b [|d1;...;dN|] converts the big array b to a
N-dimensional array of dimensions d1...dN. The returned
array and the original array b share their data
and have the same layout. For instance, assuming that b
is a one-dimensional array of dimension 12, reshape b [|3;4|]
returns a two-dimensional array b' of dimensions 3 and 4.
If b has C layout, the element (x,y) of b' corresponds
to the element x * 3 + y of b. If b has Fortran layout,
the element (x,y) of b' corresponds to the element
x + (y - 1) * 4 of b.
The returned big array must have exactly the same number of
elements as the original big array b. That is, the product
of the dimensions of b must be equal to i1 * ... * iN.
Otherwise, Invalid_arg is raised.val reshape_1 : ('a, 'b, 'c) Genarray.t -> int -> ('a, 'b, 'c) Array1.tBigarray.reshape for reshaping to one-dimensional arrays.val reshape_2 : ('a, 'b, 'c) Genarray.t ->
int -> int -> ('a, 'b, 'c) Array2.tBigarray.reshape for reshaping to two-dimensional arrays.val reshape_3 : ('a, 'b, 'c) Genarray.t ->
int -> int -> int -> ('a, 'b, 'c) Array3.tBigarray.reshape for reshaping to three-dimensional arrays.