GNU Octave Manual Version 3by John W. Eaton, David Bateman, Søren Hauberg Paperback (6"x9"), 568 pages ISBN 095461206X RRP £24.95 ($39.95) |

## 4.3 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.

__Built-in Function:__**isinteger***(*`x`)- Return true if
`x`is an integer object (int8, uint8, int16, etc.). Note that`isinteger (14)`

is false because numeric constants in expressions are double precision floating point values.See also isreal, isnumeric, class, isa

__Built-in Function:__**int8***(*`x`)- Convert
`x`to 8-bit integer type.

__Built-in Function:__**uint8***(*`x`)- Convert
`x`to unsigned 8-bit integer type.

__Built-in Function:__**int16***(*`x`)- Convert
`x`to 16-bit integer type.

__Built-in Function:__**uint16***(*`x`)- Convert
`x`to unsigned 16-bit integer type.

__Built-in Function:__**int32***(*`x`)- Convert
`x`to 32-bit integer type.

__Built-in Function:__**uint32***(*`x`)- Convert
`x`to unsigned 32-bit integer type.

__Built-in Function:__**int64***(*`x`)- Convert
`x`to 64-bit integer type.

__Built-in Function:__**uint64***(*`x`)- Convert
`x`to unsigned 64-bit integer type.

__Built-in Function:__**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`uint32`

.See also intmin, bitmax

__Built-in Function:__**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`uint32`

.See also intmax, bitmax

ISBN 095461206X | GNU Octave Manual Version 3 | See the print edition |