Data Types

Array API specification for supported data types.

A conforming implementation of the array API standard must provide and support the following data types.

bool

Boolean (True or False).

int8

An 8-bit signed integer whose values exist on the interval [-128, +127].

int16

A 16-bit signed integer whose values exist on the interval [−32,767, +32,767].

int32

A 32-bit signed integer whose values exist on the interval [−2,147,483,647, +2,147,483,647].

int64

A 64-bit signed integer whose values exist on the interval [−9,223,372,036,854,775,807, +9,223,372,036,854,775,807].

uint8

An 8-bit unsigned integer whose values exist on the interval [0, +255].

uint16

A 16-bit unsigned integer whose values exist on the interval [0, +65,535].

uint32

A 32-bit unsigned integer whose values exist on the interval [0, +4,294,967,295].

uint64

A 64-bit unsigned integer whose values exist on the interval [0, +18,446,744,073,709,551,615].

float32

IEEE 754 single-precision (32-bit) binary floating-point number (see IEEE 754-2019).

float64

IEEE 754 double-precision (64-bit) binary floating-point number (see IEEE 754-2019).

Note

IEEE 754-2019 requires support for subnormal (a.k.a., denormal) numbers, which are useful for supporting gradual underflow. However, hardware support for subnormal numbers is not universal, and many platforms (e.g., accelerators) and compilers support toggling denormals-are-zero (DAZ) and/or flush-to-zero (FTZ) behavior to increase performance and to guard against timing attacks.

Accordingly, subnormal behavior is left unspecified and, thus, implementation-defined. Conforming implementations may vary in their support for subnormal numbers.

Future extension

complex64 and complex128 data types are expected to be included in the next version of this standard and to have the following casting rules (will be added to Type Promotion Rules):

../_images/dtype_promotion_complex.png

See array-api/issues/102 for more details

Note

A conforming implementation of the array API standard may provide and support additional data types beyond those described in this specification.

Data Type Objects

Data types (“dtypes”) are objects which are used as dtype specifiers in functions and methods (e.g., zeros((2, 3), dtype=float32)).

Note

A conforming implementation may add additional methods or attributes to data type objects beyond those described in this specification.

Note

Implementations may provide other ways to specify data types (e.g., zeros((2, 3), dtype='f4')) which are not described in this specification; however, in order to ensure portability, array library consumers are recommended to use data type objects as provided by specification conforming array libraries.

A conforming implementation of the array API standard must provide and support data type objects having the following attributes and methods.

Methods

__eq__(self, other, /)

Computes the truth value of self == other in order to test for data type object equality.

Default Data Types

A conforming implementation of the array API standard must define the following default data types.

  • a default floating-point data type (either float32 or float64).

  • a default integer data type (either int32 or int64).

  • a default array index data type (either int32 or int64).

The default floating-point data type must be the same across platforms.

The default integer data type should be the same across platforms, but the default may vary depending on whether Python is 32-bit or 64-bit.

The default array index data type may be int32 on 32-bit platforms, but the default should be int64 otherwise.

Note

The default data types should be clearly defined in a conforming library’s documentation.

Data Type Categories

For the purpose of organizing functions within this specification, the following data type categories are defined.

Note

Conforming libraries are not required to organize data types according to these categories. These categories are only intended for use within this specification.

Note

Future versions of the specification will include additional categories for complex data types.

Numeric Data Types

int8, int16, int32, int64, uint8, uint16, uint32, uint64, float32, and float64 (i.e., all data types except for bool).

Integer Data Types

int8, int16, int32, int64, uint8, uint16, uint32, and uint64.

Floating-point Data Types

float32 and float64.

Boolean Data Types

bool.