[ < ] | [ > ] | [ << ] | [ Up ] | [ >> ] | [Top] | [Contents] | [Index] | [ ? ] |

### 4.4.1 Integer Arithmetic

While many numerical computations can't be carried out in integers,
Octave does support basic operations like addition and multiplication
on integers. The operators `+`

, `-`

, `.*`

, and `./`

work on integers of the same type. So, it is possible to add two 32 bit
integers, but not to add a 32 bit integer and a 16 bit integer.

The arithmetic operations on integers are performed by casting the integer values to double precision values, performing the operation, and then re-casting the values back to the original integer type. As the double precision type of Octave is only capable of representing integers with up to 53 bits of precision, it is not possible to perform arithmetic with 64 bit integer types.

When doing integer arithmetic one should consider the possibility of
underflow and overflow. This happens when the result of the computation
can't be represented using the chosen integer type. As an example it is
not possible to represent the result of *10 - 20* when using
unsigned integers. Octave makes sure that the result of integer
computations is the integer that is closest to the true result. So, the
result of *10 - 20* when using unsigned integers is zero.

When doing integer division Octave will round the result to the nearest
integer. This is different from most programming languages, where the
result is often floored to the nearest integer. So, the result of
`int32(5)./int32(8)`

is `1`

.

__Function File:__**idivide***(*`x`,`y`,`op`)Integer division with different round rules. The standard behavior of the an integer division such as

is to round the result to the nearest integer. This is not always the desired behavior and`a`./`b``idivide`

permits integer element-by-element division to be performed with different treatment for the fractional part of the division as determined by the`op`flag.`op`is a string with one of the values:- "fix"
Calculate

with the fractional part rounded towards zero.`a`./`b`- "round"
Calculate

with the fractional part rounded towards the nearest integer.`a`./`b`- "floor"
Calculate

with the fractional part rounded downwards.`a`./`b`- "ceil"
Calculate

with the fractional part rounded upwards.`a`./`b`

If

`op`is not given it is assumed that it is`"fix"`

. An example demonstrating these rounding rules isidivide (int8 ([-3, 3]), int8 (4), "fix") ⇒ int8 ([0, 0]) idivide (int8 ([-3, 3]), int8 (4), "round") ⇒ int8 ([-1, 1]) idivide (int8 ([-3, 3]), int8 (4), "ceil") ⇒ int8 ([0, 1]) idivide (int8 ([-3, 3]), int8 (4), "floor") ⇒ int8 ([-1, 0])

[ < ] | [ > ] | [ << ] | [ Up ] | [ >> ] | [Top] | [Contents] | [Index] | [ ? ] |