make-random-state (original) (raw)

ANSI Common Lisp 12 Numbers 12.2 Dictionary of Numbers

Syntax:

make-random-state &optional state new-state

Arguments and Values:

state - a random state, or nil, or t. The default is nil.

new-state - a random state object.

Description:

Creates a fresh object of type random-state suitable for use as the value of *random-state*.

If state is a random state object, the new-state is a _copy_5 of that object. If state is nil, the new-state is a _copy_5 of the current random state. If state is t, the new-state is a fresh random state _object_that has been randomly initialized by some means.

Examples:

(let* ((rs1 (make-random-state nil)) (rs2 (make-random-state t)) (rs3 (make-random-state rs2)) (rs4 nil)) (list (loop for i from 1 to 10 collect (random 100) when (= i 5) do (setq rs4 (make-random-state))) (loop for i from 1 to 10 collect (random 100 rs1)) (loop for i from 1 to 10 collect (random 100 rs2)) (loop for i from 1 to 10 collect (random 100 rs3)) (loop for i from 1 to 10 collect (random 100 rs4)))) ((29 25 72 57 55 68 24 35 54 65) (29 25 72 57 55 68 24 35 54 65) (93 85 53 99 58 62 2 23 23 59) (93 85 53 99 58 62 2 23 23 59) (68 24 35 54 65 54 55 50 59 49))

Exceptional Situations:

Should signal an error of type type-error if state is not a random state, or nil, or t.

See Also:

random, *random-state*

Notes:

One important use of make-random-state is to allow the same series of pseudo-random numbers to be generated many times within a single program.

Allegro CL Implementation Details:

See cl:random and cl:make-random-state for information on the Allegro CL implementation of make-random-state.