module Bigarray:Large, multi-dimensional, numerical arrays.sig
..end
This 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 OCaml 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 OCaml ad-hoc polymorphic operations:
=
, <>
, <=
, etc, as well as compare
);Hash
);Marshal
module, as well as output_value
and input_value
).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
float32_elt
type
float64_elt
type
complex32_elt
type
complex64_elt
type
int8_signed_elt
type
int8_unsigned_elt
type
int16_signed_elt
type
int16_unsigned_elt
type
int_elt
type
int32_elt
type
int64_elt
type
nativeint_elt
type ('a, 'b)
kind
float32_elt
contains
32-bit single precision floats, but reading or writing one of
its elements from OCaml uses the OCaml type float
, which is
64-bit double precision floats.
The abstract type ('a, 'b) kind
captures this association
of an OCaml 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 OCaml types with
element kinds:
val float32 : (float, float32_elt) kind
Bigarray.char
.val float64 : (float, float64_elt) kind
Bigarray.char
.val complex32 : (Complex.t, complex32_elt) kind
Bigarray.char
.val complex64 : (Complex.t, complex64_elt) kind
Bigarray.char
.val int8_signed : (int, int8_signed_elt) kind
Bigarray.char
.val int8_unsigned : (int, int8_unsigned_elt) kind
Bigarray.char
.val int16_signed : (int, int16_signed_elt) kind
Bigarray.char
.val int16_unsigned : (int, int16_unsigned_elt) kind
Bigarray.char
.val int : (int, int_elt) kind
Bigarray.char
.val int32 : (int32, int32_elt) kind
Bigarray.char
.val int64 : (int64, int64_elt) kind
Bigarray.char
.val nativeint : (nativeint, nativeint_elt) kind
Bigarray.char
.val char : (char, int8_unsigned_elt) kind
float32_elt
and float64_elt
are
accessed using the OCaml type float
. Big arrays of complex kinds
complex32_elt
, complex64_elt
are accessed with the OCaml type
Complex.t
. Big arrays of
integer kinds are accessed using the smallest OCaml integer
type large enough to represent the array elements:
int
for 8- and 16-bit integer bigarrays, as well as OCaml-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
.type
c_layout
type
fortran_layout
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
.
The abstract values c_layout
and fortran_layout
represent
the two supported layouts at the level of values.
val c_layout : c_layout layout
val fortran_layout : fortran_layout layout
module Genarray:sig
..end
module Array1:sig
..end
module Array2:sig
..end
module Array3:sig
..end
val genarray_of_array1 : ('a, 'b, 'c) Array1.t -> ('a, 'b, 'c) Genarray.t
val genarray_of_array2 : ('a, 'b, 'c) Array2.t -> ('a, 'b, 'c) Genarray.t
val genarray_of_array3 : ('a, 'b, 'c) Array3.t -> ('a, 'b, 'c) Genarray.t
val array1_of_genarray : ('a, 'b, 'c) Genarray.t -> ('a, 'b, 'c) Array1.t
Invalid_argument
if the generic big array
does not have exactly one dimension.val array2_of_genarray : ('a, 'b, 'c) Genarray.t -> ('a, 'b, 'c) Array2.t
Invalid_argument
if the generic big array
does not have exactly two dimensions.val array3_of_genarray : ('a, 'b, 'c) Genarray.t -> ('a, 'b, 'c) Array3.t
Invalid_argument
if the generic big array
does not have exactly three dimensions.val reshape : ('a, 'b, 'c) Genarray.t ->
int array -> ('a, 'b, 'c) Genarray.t
reshape 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_argument
is raised.val reshape_1 : ('a, 'b, 'c) Genarray.t -> int -> ('a, 'b, 'c) Array1.t
Bigarray.reshape
for reshaping to
one-dimensional arrays.val reshape_2 : ('a, 'b, 'c) Genarray.t ->
int -> int -> ('a, 'b, 'c) Array2.t
Bigarray.reshape
for reshaping to
two-dimensional arrays.val reshape_3 : ('a, 'b, 'c) Genarray.t ->
int -> int -> int -> ('a, 'b, 'c) Array3.t
Bigarray.reshape
for reshaping to
three-dimensional arrays.