4.4 Integer Data Types

Octave supports integer matrices as an alternative to using double precision. It is possible to use both signed and unsigned integers represented by 8, 16, 32, or 64 bits. It should be noted that most computations require floating point data, meaning that integers will often change type when involved in numeric computations. For this reason integers are most often used to store data, and not for calculations.

In general most integer matrices are created by casting existing matrices to integers. The following example shows how to cast a matrix into 32 bit integers.

float = rand (2, 2)
     ⇒ float = 0.37569   0.92982
                0.11962   0.50876
integer = int32 (float)
     ⇒ integer = 0  1
                  0  1

As can be seen, floating point values are rounded to the nearest integer when converted.

: isinteger (x)

Return true if x is an integer object (int8, uint8, int16, etc.).

Note that isinteger (14) is false because numeric constants in Octave are double precision floating point values.

See also: isfloat, ischar, islogical, isnumeric, isa.

: int8 (x)

Convert x to 8-bit integer type.

See also: uint8, int16, uint16, int32, uint32, int64, uint64.

: uint8 (x)

Convert x to unsigned 8-bit integer type.

See also: int8, int16, uint16, int32, uint32, int64, uint64.

: int16 (x)

Convert x to 16-bit integer type.

See also: int8, uint8, uint16, int32, uint32, int64, uint64.

: uint16 (x)

Convert x to unsigned 16-bit integer type.

See also: int8, uint8, int16, int32, uint32, int64, uint64.

: int32 (x)

Convert x to 32-bit integer type.

See also: int8, uint8, int16, uint16, uint32, int64, uint64.

: uint32 (x)

Convert x to unsigned 32-bit integer type.

See also: int8, uint8, int16, uint16, int32, int64, uint64.

: int64 (x)

Convert x to 64-bit integer type.

See also: int8, uint8, int16, uint16, int32, uint32, uint64.

: uint64 (x)

Convert x to unsigned 64-bit integer type.

See also: int8, uint8, int16, uint16, int32, uint32, int64.

: intmax (type)

Return the largest integer that can be represented in an integer type.

The variable type can be

int8

signed 8-bit integer.

int16

signed 16-bit integer.

int32

signed 32-bit integer.

int64

signed 64-bit integer.

uint8

unsigned 8-bit integer.

uint16

unsigned 16-bit integer.

uint32

unsigned 32-bit integer.

uint64

unsigned 64-bit integer.

The default for type is int32.

See also: intmin, flintmax.

: intmin (type)

Return the smallest integer that can be represented in an integer type.

The variable type can be

int8

signed 8-bit integer.

int16

signed 16-bit integer.

int32

signed 32-bit integer.

int64

signed 64-bit integer.

uint8

unsigned 8-bit integer.

uint16

unsigned 16-bit integer.

uint32

unsigned 32-bit integer.

uint64

unsigned 64-bit integer.

The default for type is int32.

See also: intmax, flintmax.

: flintmax ()

: flintmax ("double")

: flintmax ("single")

Return the largest integer that can be represented consecutively in a floating point value.

The default class is "double", but "single" is a valid option. On IEEE 754 compatible systems, flintmax is 2^{53} for "double" and 2^{24} for "single".

See also: intmax, realmax, realmin.