Module Stdlib.Bigarray

Contents

Instructions: Use this module in your project

In the IDE (CLion, Visual Studio Code, Xcode, etc.) you use for your DkSDK project:

  1. Add the following to your project's dependencies/CMakeLists.txt:

    Copy
    DkSDKProject_DeclareAvailable(ocaml
    CONSTRAINT "= 4.14.0"
    FINDLIBS str unix runtime_events threads dynlink)
DkSDKProject_MakeAvailable(ocaml)

  2. Add the Findlib::ocaml library to any desired targets in src/*/CMakeLists.txt:

    Copy
    target_link_libraries(YourPackage_YourLibraryName
     # ... existing libraries, if any ...
     Findlib::ocaml)

  3. Click your IDE's Build button

Not using DkSDK?

FIRST, do one or all of the following:

  1. Run:

    Copy
    opam install ocaml.4.14.0

  2. Edit your dune-project and add:

    Copy
    (package
  (name YourExistingPackage)
  (depends
  ; ... existing dependenices ...
  (ocaml (>= 4.14.0))))

    Then run:

    Copy
    dune build *.opam # if this fails, run: dune build

  3. Edit your <package>.opam file and add:

    Copy
    depends: [
  # ... existing dependencies ...
  "ocaml" {>= "4.14.0"}
]

    Then run:

    Copy
    opam install . --deps-only

FINALLY, add the library to any desired (library)and/or (executable) targets in your **/dune files:

Copy
(library
  (name YourLibrary)
  ; ... existing library options ...
  (libraries
    ; ... existing libraries ...
    ))

(executable
  (name YourExecutable)
  ; ... existing executable options ...
  (libraries
    ; ... existing libraries ...
    ))

Element kinds

Bigarrays can contain elements of the following kinds:

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).

  • since 4.07.0 Moved from otherlibs to stdlib.
typefloat32_elt`` =

    

  1. 

| Float32_elt
typefloat64_elt`` =

    

  1. 

| Float64_elt
typeint8_signed_elt`` =

    

  1. 

| Int8_signed_elt
typeint8_unsigned_elt`` =

    

  1. 

| Int8_unsigned_elt
typeint16_signed_elt`` =

    

  1. 

| Int16_signed_elt
typeint16_unsigned_elt`` =

    

  1. 

| Int16_unsigned_elt
typeint32_elt`` =

    

  1. 

| Int32_elt
typeint64_elt`` =

    

  1. 

| Int64_elt
typeint_elt`` =

    

  1. 

| Int_elt
typenativeint_elt`` =

    

  1. 

| Nativeint_elt
typecomplex32_elt`` =

    

  1. 

| Complex32_elt
typecomplex64_elt`` =

    

  1. 

| Complex64_elt
type``('a, 'b) kind`` =

    

  1. 

| Float32: ``(float,float32_elt)`` kind
    

  1. 

| Float64: ``(float,float64_elt)`` kind
    

  1. 

| Int8_signed: ``(int,int8_signed_elt)`` kind
    

  1. 

| Int8_unsigned: ``(int,int8_unsigned_elt)`` kind
    

  1. 

| Int16_signed: ``(int,int16_signed_elt)`` kind
    

  1. 

| Int16_unsigned: ``(int,int16_unsigned_elt)`` kind
    

  1. 

| Int32: ``(int32,int32_elt)`` kind
    

  1. 

| Int64: ``(int64,int64_elt)`` kind
    

  1. 

| Int: ``(int,int_elt)`` kind
    

  1. 

| Nativeint: ``(nativeint,nativeint_elt)`` kind
    

  1. 

| Complex32 : ``(Complex.t, complex32_elt)`` kind
    

  1. 

| Complex64 : ``(Complex.t, complex64_elt)`` kind
    

  1. 

| Char: ``(char,int8_unsigned_elt)`` kind

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 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 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 re-exported below for backward-compatibility reasons.

Using a generalized algebraic datatype (GADT) here allows writing well-typed polymorphic functions whose return type depend on the argument type, such as:

Copy 
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'
valfloat32 : ``(float,float32_elt)`` kind

See Bigarray.char.

valfloat64 : ``(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.

valint8_signed : ``(int,int8_signed_elt)`` kind

See Bigarray.char.

valint8_unsigned : ``(int,int8_unsigned_elt)`` kind

See Bigarray.char.

valint16_signed : ``(int,int16_signed_elt)`` kind

See Bigarray.char.

valint16_unsigned : ``(int,int16_unsigned_elt)`` kind

See Bigarray.char.

valint : ``(int,int_elt)`` kind

See Bigarray.char.

valint32 : ``(int32,int32_elt)`` kind

See Bigarray.char.

valint64 : ``(int64,int64_elt)`` kind

See Bigarray.char.

valnativeint : ``(nativeint,nativeint_elt)`` kind

See Bigarray.char.

valchar : ``(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 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, 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.

  • since 4.03.0

Array layouts

typec_layout`` =

    

  1. 

| C_layout_typ

See Bigarray.fortran_layout.

typefortran_layout`` =

    

  1. 

| 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 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 phantom types Bigarray.c_layout and Bigarray.fortran_layout respectively.

Supported layouts

The GADT type 'a layout represents one of the two supported memory layouts: C-style or Fortran-style. Its constructors are re-exported as values below for backward-compatibility reasons.

type``'a layout`` =

    

  1. 

| C_layout:c_layout layout
    

  1. 

| Fortran_layout:fortran_layout layout
valc_layout :c_layout layout
valfortran_layout :fortran_layout layout

\Generic arrays (of arbitrarily many dimensions)

module Genarray:sig...end

Zero-dimensional arrays

module Array0:sig...end

Zero-dimensional arrays. The Array0 structure provides operations similar to those of Bigarray.Genarray, but specialized to the case of zero-dimensional arrays that only contain a single scalar value. Statically knowing the number of dimensions of the array allows faster operations, and more precise static type-checking.

One-dimensional arrays

module Array1:sig...end

One-dimensional arrays. The Array1 structure provides operations similar to those of Bigarray.Genarray, but specialized to the case of one-dimensional arrays. (The Array2 and Array3 structures below provide operations specialized for two- and three-dimensional arrays.) Statically knowing the number of dimensions of the array allows faster operations, and more precise static type-checking.

Two-dimensional arrays

module Array2:sig...end

Two-dimensional arrays. The Array2 structure provides operations similar to those of Bigarray.Genarray, but specialized to the case of two-dimensional arrays.

Three-dimensional arrays

module Array3:sig...end

Three-dimensional arrays. The Array3 structure provides operations similar to those of Bigarray.Genarray, but specialized to the case of three-dimensional arrays.

\Coercions between generic Bigarrays and fixed-dimension Bigarrays

val genarray_of_array0 : ``('a, 'b, 'c)`` Array0.t -> ``('a, 'b, 'c)`` Genarray.t

Return the generic Bigarray corresponding to the given zero-dimensional Bigarray.

  • since 4.05.0
val genarray_of_array1 : ``('a, 'b, 'c)`` Array1.t -> ``('a, 'b, 'c)`` Genarray.t

Return the generic Bigarray corresponding to the given one-dimensional Bigarray.

val genarray_of_array2 : ``('a, 'b, 'c)`` Array2.t -> ``('a, 'b, 'c)`` Genarray.t

Return the generic Bigarray corresponding to the given two-dimensional Bigarray.

val genarray_of_array3 : ``('a, 'b, 'c)`` Array3.t -> ``('a, 'b, 'c)`` Genarray.t

Return the generic Bigarray corresponding to the given three-dimensional Bigarray.

val array0_of_genarray : ``('a, 'b, 'c)`` Genarray.t -> ``('a, 'b, 'c)`` Array0.t

Return the zero-dimensional Bigarray corresponding to the given generic Bigarray.

  • raises Invalid_argument

    if the generic Bigarray does not have exactly zero dimension.

  • since 4.05.0

val array1_of_genarray : ``('a, 'b, 'c)`` Genarray.t -> ``('a, 'b, 'c)`` Array1.t

Return the one-dimensional Bigarray corresponding to the given generic Bigarray.

  • raises 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 two-dimensional Bigarray corresponding to the given generic Bigarray.

  • raises 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 three-dimensional Bigarray corresponding to the given generic Bigarray.

  • raises Invalid_argument

    if the generic Bigarray does not have exactly three dimensions.

Re-shaping Bigarrays

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 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 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 zero-dimensional arrays.

  • since 4.05.0
val reshape_1 : ``('a, 'b, 'c)`` Genarray.t ->``int-> ``('a, 'b, 'c)`` Array1.t

Specialized version of Bigarray.reshape for reshaping to one-dimensional arrays.

val reshape_2 : ``('a, 'b, 'c)`` Genarray.t ->``int->``int-> ``('a, 'b, 'c)`` Array2.t

Specialized version of Bigarray.reshape for reshaping to two-dimensional 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 three-dimensional arrays.

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