module Bigarray: sig .. end
Large, multidimensional, numerical arrays.
This module implements multidimensional arrays of integers and floatingpoint numbers, thereafter referred to as 'Bigarrays', to distinguish them from the standard OCaml arrays described in Array
.
The implementation allows efficient sharing of large numerical arrays between OCaml code and C or Fortran numerical libraries.
The main differences between 'Bigarrays' and standard OCaml arrays are as follows:
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
.
Bigarrays support all the OCaml adhoc polymorphic operations:
=
, <>
, <=
, etc, as well as compare
);Hash
);Marshal
module, as well as output_value
and input_value
).Bigarrays can contain elements of the following 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
).Each element kind is represented at the type level by one of the *_elt
types defined below (defined with a single constructor instead of abstract types for technical injectivity reasons).
type float32_elt =

 Float32_elt

type float64_elt =

 Float64_elt

type int8_signed_elt =

 Int8_signed_elt

type int8_unsigned_elt =

 Int8_unsigned_elt

type int16_signed_elt =

 Int16_signed_elt

type int16_unsigned_elt =

 Int16_unsigned_elt

type int32_elt =

 Int32_elt

type int64_elt =

 Int64_elt

type int_elt =

 Int_elt

type nativeint_elt =

 Nativeint_elt

type complex32_elt =

 Complex32_elt

type complex64_elt =

 Complex64_elt

type ('a, 'b) kind =

 Float32 :


 Float64 :


 Int8_signed :


 Int8_unsigned :


 Int16_signed :


 Int16_unsigned :


 Int32 :


 Int64 :


 Int :


 Nativeint :


 Complex32 :


 Complex64 :


 Char :

To each element kind is associated an OCaml type, which is the type of OCaml values that can be stored in the Bigarray or read back from it. This type is not necessarily the same as the type of the array elements proper: for instance, a Bigarray whose elements are of kind float32_elt
contains 32bit single precision floats, but reading or writing one of its elements from OCaml uses the OCaml type float
, which is 64bit double precision floats.
The GADT type ('a, 'b) kind
captures this association of an OCaml type 'a
for values read or written in the Bigarray, and of an element kind 'b
which represents the actual contents of the Bigarray. Its constructors list all possible associations of OCaml types with element kinds, and are reexported below for backwardcompatibility reasons.
Using a generalized algebraic datatype (GADT) here allows writing welltyped polymorphic functions whose return type depend on the argument type, such as:
let zero : type a b. (a, b) kind > a = function  Float32 > 0.0  Complex32 > Complex.zero  Float64 > 0.0  Complex64 > Complex.zero  Int8_signed > 0  Int8_unsigned > 0  Int16_signed > 0  Int16_unsigned > 0  Int32 > 0l  Int64 > 0L  Int > 0  Nativeint > 0n  Char > '\000'
val float32 : (float, float32_elt) kind
See Bigarray.char
.
val float64 : (float, float64_elt) kind
See Bigarray.char
.
val complex32 : (Complex.t, complex32_elt) kind
See Bigarray.char
.
val complex64 : (Complex.t, complex64_elt) kind
See Bigarray.char
.
val int8_signed : (int, int8_signed_elt) kind
See Bigarray.char
.
val int8_unsigned : (int, int8_unsigned_elt) kind
See Bigarray.char
.
val int16_signed : (int, int16_signed_elt) kind
See Bigarray.char
.
val int16_unsigned : (int, int16_unsigned_elt) kind
See Bigarray.char
.
val int : (int, int_elt) kind
See Bigarray.char
.
val int32 : (int32, int32_elt) kind
See Bigarray.char
.
val int64 : (int64, int64_elt) kind
See Bigarray.char
.
val nativeint : (nativeint, nativeint_elt) kind
See Bigarray.char
.
val char : (char, int8_unsigned_elt) kind
As shown by the types of the values above, Bigarrays of kind float32_elt
and float64_elt
are accessed using the OCaml type float
. Bigarrays of complex kinds complex32_elt
, complex64_elt
are accessed with the OCaml type Complex.t
. Bigarrays of integer kinds are accessed using the smallest OCaml integer type large enough to represent the array elements: int
for 8 and 16bit integer Bigarrays, as well as OCamlinteger Bigarrays; int32
for 32bit integer Bigarrays; int64
for 64bit integer Bigarrays; and nativeint
for platformnative integer Bigarrays. Finally, Bigarrays 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
.
val kind_size_in_bytes : ('a, 'b) kind > int
kind_size_in_bytes k
is the number of bytes used to store an element of type k
.
type c_layout =

 C_layout_typ

type fortran_layout =

 Fortran_layout_typ

To facilitate interoperability with existing C and Fortran code, this library supports two different memory layouts for Bigarrays, one compatible with the C conventions, the other compatible with the Fortran conventions.
In the Cstyle layout, array indices start at 0, and multidimensional arrays are laid out in rowmajor format. That is, for a twodimensional 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 Fortranstyle layout, array indices start at 1, and multidimensional arrays are laid out in columnmajor format. That is, for a twodimensional 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 phantom types Bigarray.c_layout
and Bigarray.fortran_layout
respectively.
The GADT type 'a layout
represents one of the two supported memory layouts: Cstyle or Fortranstyle. Its constructors are reexported as values below for backwardcompatibility reasons.
type 'a layout =

 C_layout :


 Fortran_layout :

val c_layout : c_layout layout
val fortran_layout : fortran_layout layout
module Genarray: sig .. end
module Array0: sig .. end
Zerodimensional arrays.
module Array1: sig .. end
Onedimensional arrays.
module Array2: sig .. end
Twodimensional arrays.
module Array3: sig .. end
Threedimensional arrays.
val genarray_of_array0 : ('a, 'b, 'c) Array0.t > ('a, 'b, 'c) Genarray.t
Return the generic Bigarray corresponding to the given zerodimensional Bigarray.
val genarray_of_array1 : ('a, 'b, 'c) Array1.t > ('a, 'b, 'c) Genarray.t
Return the generic Bigarray corresponding to the given onedimensional Bigarray.
val genarray_of_array2 : ('a, 'b, 'c) Array2.t > ('a, 'b, 'c) Genarray.t
Return the generic Bigarray corresponding to the given twodimensional Bigarray.
val genarray_of_array3 : ('a, 'b, 'c) Array3.t > ('a, 'b, 'c) Genarray.t
Return the generic Bigarray corresponding to the given threedimensional Bigarray.
val array0_of_genarray : ('a, 'b, 'c) Genarray.t > ('a, 'b, 'c) Array0.t
Return the zerodimensional Bigarray corresponding to the given generic Bigarray.
Invalid_argument
if the generic Bigarray does not have exactly zero dimension.val array1_of_genarray : ('a, 'b, 'c) Genarray.t > ('a, 'b, 'c) Array1.t
Return the onedimensional Bigarray corresponding to the given generic Bigarray.
Invalid_argument
if the generic Bigarray does not have exactly one dimension.val array2_of_genarray : ('a, 'b, 'c) Genarray.t > ('a, 'b, 'c) Array2.t
Return the twodimensional Bigarray corresponding to the given generic Bigarray.
Invalid_argument
if the generic Bigarray does not have exactly two dimensions.val array3_of_genarray : ('a, 'b, 'c) Genarray.t > ('a, 'b, 'c) Array3.t
Return the threedimensional Bigarray corresponding to the given generic Bigarray.
Invalid_argument
if the generic Bigarray 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 Bigarray 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 onedimensional array of dimension 12, reshape b [3;4]
returns a twodimensional 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 Bigarray must have exactly the same number of elements as the original Bigarray b
. That is, the product of the dimensions of b
must be equal to i1 * ... * iN
. Otherwise, Invalid_argument
is raised.
val reshape_0 : ('a, 'b, 'c) Genarray.t > ('a, 'b, 'c) Array0.t
Specialized version of Bigarray.reshape
for reshaping to zerodimensional arrays.
val reshape_1 : ('a, 'b, 'c) Genarray.t > int > ('a, 'b, 'c) Array1.t
Specialized version of Bigarray.reshape
for reshaping to onedimensional arrays.
val reshape_2 : ('a, 'b, 'c) Genarray.t > int > int > ('a, 'b, 'c) Array2.t
Specialized version of Bigarray.reshape
for reshaping to twodimensional arrays.
val reshape_3 : ('a, 'b, 'c) Genarray.t > int > int > int > ('a, 'b, 'c) Array3.t
Specialized version of Bigarray.reshape
for reshaping to threedimensional arrays.
© INRIA 19952020.
https://www.ocaml.org/releases/4.11/htmlman/libref/Bigarray.html