[ Arithmetic | Reference Manual | Alphabetic Index ]

# seed(+Seed)

Sets the initial seed Seed for generating random numbers with random/1 or frandom/1.

Seed
  Integer.

## Description

Used to initialise the seed which is used for the generation of random numbers by random/1 or frandom/1. Setting the same seed value with seed/1 enables the generation of a repeatable random sequence with random/1 ie. pseudo-random number generation.

The seed value should be an integer in the range 1 .. 2^31-1.

### Modes and Determinism

- seed(+) is det

### Exceptions

(4) instantiation fault
  Seed is not instantiated.
(5) type error
  Seed is instantiated, but not to an integer.

## Examples

    Success:
          ?- repeat, random(S).
          S = 464880439   More? (;)
          S = 285401533   More? (;)
          yes.

          ?- seed(1), repeat, random(S).
          S = 2078917053   More? (;)
          S = 143302914   More? (;)
          yes.
          ?- seed(1), repeat, random(S).
          S = 2078917053   More? (;)
          S = 143302914   More? (;)
          yes.

## See Also

random / 1